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Whichever type of data an observer collects (see Quantifying Ecology 1.1), the process of interpretation typically begins with a graphical display of observations. The most common method of displaying a single data set is constructing a **frequency distribution**. A frequency distribution is a count of the number of ob... | {
"Header 1": "QUANTIFYING ECOLOGY 1.2 Displaying Ecological Data: Histograms and Scatter Plots",
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Scientists use the understanding derived from observation and experiments to develop models. Data are limited to the special case of what happened when the measurements were made. Like photographs, data represent a given place and time. Models use the understanding gained from the data to predict what will happen in so... | {
"Header 1": "1.6 Models Provide a Basis for Predictions",
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Collecting observations, developing and testing hypotheses, and constructing predictive models all form the backbone of the scientific method (see Figure 1.4). It is a continuous process of testing and correcting concepts to arrive at explanations for the variation we observe in the world around us, thus unifying obser... | {
"Header 1": "1.7 Uncertainty Is an Inherent Feature of Science",
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The complex interactions taking place within ecological systems involve all kinds of physical, chemical, and biological processes. To study these interactions, ecologists must draw on other sciences. This dependence makes ecology an interdisciplinary science.
Although we explore topics that are typically the subject ... | {
"Header 1": "1.8 Ecology Has Strong Ties to Other Disciplines",
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As we noted previously, ecology encompasses a broad area of investigation—from the individual organism to the biosphere. Our study of the science of ecology uses this hierarchical framework in the chapters that follow. We begin with the individual organism, examining the processes it uses and constraints it faces in ma... | {
"Header 1": "1.9 The Individual Is the Basic Unit of Ecology",
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The genealogy of most sciences is direct. Tracing the roots of chemistry and physics is relatively easy. The science of ecology is different. Its roots are complex and intertwined with a wide array of scientific advances that have occurred in other disciplines within the biological and physical sciences. Although the t... | {
"Header 1": "Ecologic al Issues & Applications",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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Developing his theory of evolution and the origin of species, Darwin came across the writings of Thomas Malthus (1766–1834). An economist, Malthus advanced the principle that populations grow in a geometric fashion, doubling at regular intervals until they outstrip the food supply. Ultimately, a "strong, constantly ope... | {
"Header 1": "Ecologic al Issues & Applications",
"Header 3": "Ecology Has a Rich History",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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#### Ecology 1.1
Ecology is the scientific study of the relationships between organisms and their environment. The environment includes the physical and chemical conditions and biological or living components of an organism's surroundings. Relationships include interactions with the physical world as well as with mem... | {
"Header 1": "Ecologic al Issues & Applications",
"Header 3": "S ummary",
"token_count": 1748,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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- 2.1 Surface Temperatures Reflect the Difference between Incoming and Outgoing Radiation
- 2.2 Intercepted Solar Radiation and Surface Temperatures Vary Seasonally
- 2.3 Geographic Difference in Surface Net Radiation Result in Global Patterns of Atmospheric Circulation
- 2.4 Surface Winds and Earth's Rotation Create O... | {
"Header 1": "Ecologic al Issues & Applications",
"Header 3": "Chapter Guide",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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Solar radiation—the electromagnetic energy (Figure 2.1) emanating from the Sun—travels more or less unimpeded through the vacuum of space until it reaches Earth's atmosphere. Scientists conceptualize solar radiation as a stream of photons, or packets of energy, that-in one of the great paradoxes of science—behave eithe... | {
"Header 1": "2.1 Surface Temperatures Reflect the Difference between Incoming and Outgoing Radiation",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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Although the variation in shortwave (solar) radiation reaching Earth's surface with latitude can explain the gradient of decreasing mean annual temperature from the equator to the poles, it does not explain the systematic variation occurring over the course of a year. What gives rise to the seasons on Earth? Why do the... | {
"Header 1": "2.2 Intercepted Solar Radiation and Surface Temperatures Vary Seasonally",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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As we discussed in the previous section, the average net radiation of the planet is zero; that is to say that the amount of incoming shortwave radiation absorbed by the surface is offset by the quantity of outgoing longwave radiation back into space. Otherwise, the average temperature of the planet would either increas... | {
"Header 1": "2.3 Geographic Difference in Surface Net Radiation Result in Global Patterns of Atmospheric Circulation",
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They are separated by a boundary called the *polar front*—a zone of low pressure (the **subpolar low**) where surface air converges and rises. Some of the rising air moves southward until it reaches approximately 30° latitude (the region of the subtropical high), where it sinks back to the surface and closes the second... | {
"Header 1": "2.3 Geographic Difference in Surface Net Radiation Result in Global Patterns of Atmospheric Circulation",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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The global pattern of prevailing winds plays a crucial role in determining major patterns of surface water flow in Earth's oceans. These systematic patterns of water movement are called *currents*. In fact, until they encounter one of the continents, the major ocean currents generally mimic the movement of the surface ... | {
"Header 1": "2.4 Surface Winds and Earth's Rotation Create Ocean Currents",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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Air temperature plays a crucial role in the exchange of water between the atmosphere and Earth's surface. Whenever matter, including water, changes from one state to another, energy is either absorbed or released. The amount of energy released or absorbed (per gram) during a change of state is known as *latent heat* (f... | {
"Header 1": "2.5 Temperature Influences the Moisture Content of Air",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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By bringing together patterns of temperature, winds, and ocean currents, we are ready to understand the global pattern of precipitation. Precipitation is not evenly distributed across Earth (Figure 2.16). At first the global map of annual precipitation in Figure 2.16 may seem to have no discernible pattern or regularit... | {
"Header 1": "2.6 Precipitation Has a Distinctive Global Pattern",
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At the continental scale, an important influence on climate is the relationship between land and water. Land surfaces heat and cool more rapidly than water as a result of differences in their specific heat. Specific heat is the amount of thermal energy necessary to raise the temperature of one gram of a substance by 1°... | {
"Header 1": "2.7 Proximity to the Coastline Influences Climate",
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Mountainous topography influences local and regional patterns of climate. Most obvious is the relationship between elevation and temperature. In the lower regions of the atmosphere (up to altitudes of approximately 12 km), temperature decreases with altitude at a fairly uniform rate because of declining air density and... | {
"Header 1": "2.8 Topography Influences Regional and Local Patterns of Climate",
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The patterns of temporal variation in climate that we have discussed thus far occur at regular and predictable intervals: seasonal changes in temperature with the rotation of Earth around the Sun, and migration of the ITCZ with the resultant seasonality of rainfall in the tropics and monsoons in Southeast Asia. Not all... | {
"Header 1": "2.9 Irregular Variations in Climate Occur at the Regional Scale",
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Most organisms live in local conditions that do not match the general climate profile of the larger region surrounding them. For example, today's weather report may state that the temperature is 28°C and the sky is clear. However, your weather forecaster is painting only a general picture. Actual conditions of specific... | {
"Header 1": "2.10 Most Organisms Live in Microclimates",
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Since the middle of the 19th century, direct measurements of surface temperature have been made at widespread locations around the world. These direct measures from instruments such as thermometers are referred to as the *instrumental record*. Besides these measurements made at the land surface, observations of sea sur... | {
"Header 1": "Ecologic al Issues & Applications",
"Header 3": "Rising Atmospheric Concentrations of Greenhouse Gases Are Altering Earth's Climate",
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What accounts for the fact that the period of Jun–Aug in the arctic region (north of 60° N) shows the least warming, while the same period corresponds to the maximum temperature change in the Antarctic (south of 60° S)?*
winter warming becomes more apparent when the seasonal data are analyzed by latitude (see Figure ... | {
"Header 1": "Ecologic al Issues & Applications",
"Header 3": "Rising Atmospheric Concentrations of Greenhouse Gases Are Altering Earth's Climate",
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#### Net Radiation 2.1
Earth intercepts solar energy in the form of shortwave radiation, some of which is reflected back into space. Earth emits energy back into space in the form of longwave radiation, a portion of which is absorbed by gases in the atmosphere and radiated back to the surface. The difference between ... | {
"Header 1": "Ecologic al Issues & Applications",
"Header 3": "S ummary",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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- **1.** What is net radiation?
- **2.** Explain the greenhouse effect phenomenon. How does our planet maintain an average surface temperature of 15ºC?
- **3.** Why do equatorial regions receive more solar radiation than the polar regions? What is the consequence to latitudinal patterns of temperature?
- **4.** The 23.... | {
"Header 1": "Ecologic al Issues & Applications",
"Header 3": "S tudy Questi o n s",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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- 3.1 Water Cycles between Earth and the Atmosphere
- 3.2 Water Has Important Physical Properties
- 3.3 Light Varies with Depth in Aquatic Environments
- 3.4 Temperature Varies with Water Depth
- 3.5 Water Functions as a Solvent
- 3.6 Oxygen Diffuses from the Atmosphere to the Surface Waters
- 3.7 Acidity Has a Widespr... | {
"Header 1": "Ecologic al Issues & Applications",
"Header 3": "Chapter Guide",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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All marine and freshwater aquatic environments are linked, either directly or indirectly, as components of the water cycle (also referred to as the hydrologic cycle; Figure 3.1)—the process by which water travels in a sequence from the air to Earth and returns to the atmosphere.
Solar radiation, which heats Earth's a... | {
"Header 1": "3.1 Water Cycles between Earth and the Atmosphere",
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The physical arrangement of its component molecules makes water a unique substance. A molecule of water consists of two atoms of hydrogen (H) joined to one atom of oxygen (O), represented by the chemical symbol H<sub>2</sub>O. The H atoms are bonded to the O atom asymmetrically, such that the two H atoms are at one end... | {
"Header 1": "3.2 Water Has Important Physical Properties",
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When light strikes the surface of water, a certain amount is reflected back to the atmosphere. The amount of light reflected from the surface depends on the angle at which the light strikes the surface. The lower the angle, the larger the amount of light reflected. As a result, the amount of light reflected from the wa... | {
"Header 1": "3.3 Light Varies with Depth in Aquatic Environments",
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Surface temperatures reflect the balance of incoming and outgoing radiation (see Section 2.1). As solar radiation is absorbed in the vertical water column, the temperature profile with depth might be expected to resemble the vertical profile of light shown in Figure 3.7—that is, decreasing exponentially with depth. How... | {
"Header 1": "3.4 Temperature Varies with Water Depth",
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As you stir a spoonful of sugar into a glass of water, it dissolves, forming a homogeneous, or uniform, mixture. A liquid that is a homogeneous mixture of two or more substances is called a **solution**. The dissolving agent of a solution is the **solvent**, and the substance that is dissolved is referred to as the **s... | {
"Header 1": "3.5 Water Functions as a Solvent",
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Water's role as a solvent is not limited to dissolving solids. The surface of a body of water defines a boundary with the atmosphere. Across this boundary, gases are exchanged through
**Figure 3.11** Composition of seawater of 35 practical salinity units (psu). Na<sup>+</sup>, sodium; Cl... | {
"Header 1": "3.6 Oxygen Diffuses from the Atmosphere to the Surface Waters",
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The solubility of carbon dioxide is somewhat different from that of oxygen in its chemical reaction with water. Water has a considerable capacity to absorb carbon dioxide, which is abundant in both freshwater and saltwater. Upon diffusing into the surface, carbon dioxide reacts with water to produce carbonic acid ( $H_... | {
"Header 1": "3.7 Acidity Has a Widespread Influence on Aquatic Environments",
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The movement of water—currents in streams and waves in an open body of water or breaking on a shore—determines the nature of many aquatic environments. The velocity of a current molds the character and structure of a stream. The shape and steepness of the stream channel, its width, depth, and roughness of the bottom, a... | {
"Header 1": "3.8 Water Movements Shape Freshwater and Marine Environments",
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Tides profoundly influence the rhythm of life on ocean shores. Tides result from the gravitational pulls of the Sun and the Moon, each of which causes two bulges (tides) in the waters of the oceans. The two bulges caused by the Moon occur at the same time on opposite sides of Earth on an imaginary line extending from t... | {
"Header 1": "3.9 Tides Dominate the Marine Coastal Environment",
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Water from streams and rivers eventually drains into the sea. The place where freshwater mixes with saltwater is called an **estuary**. Temperatures in estuaries fluctuate considerably, both daily and seasonally. Sun and inflowing and tidal currents heat the water. High tide on the mudflats may heat or cool the water, ... | {
"Header 1": "3.10 The Transition Zone between Freshwater and Saltwater Environments Presents Unique Constraints",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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The exchange of carbon dioxide $(CO_2)$ between the atmosphere and the surface waters of the oceans is governed by the process of diffusion, with the net exchange moving $CO_2$ from higher concentrations (atmosphere) to lower concentrations (surface waters) (Section 3.7). Upon diffusing into the surface, the $CO_2... | {
"Header 1": "Rising Atmospheric Concentrations of CO<sub>2</sub> Are Impacting Ocean Acidity",
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(Photograph by David Littschwager/National Geographic Society.)
#### S ummary
#### The Water Cycle 3.1
Water follows a cycle, traveling from the air to Earth and returning to the atmosphere. It moves through cloud formation in the atmosphere, precipitation, interception, and infiltration into the ground. It eve... | {
"Header 1": "Rising Atmospheric Concentrations of CO<sub>2</sub> Are Impacting Ocean Acidity",
"token_count": 1942,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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- 4.1 Life on Land Imposes Unique Constraints
- 4.2 Plant Cover Influences the Vertical Distribution of Light
- 4.3 Soil Is the Foundation upon which All Terrestrial Life Depends
- 4.4 The Formation of Soil Begins with Weathering
- 4.5 Soil Formation Involves Five Interrelated Factors
- 4.6 Soils Have Certain Distingui... | {
"Header 1": "Rising Atmospheric Concentrations of CO<sub>2</sub> Are Impacting Ocean Acidity",
"Header 3": "Chapter Guide",
"token_count": 477,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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The transition from life in aquatic environments to life on land brought with it a variety of constraints. Perhaps the greatest constraint imposed by terrestrial environments is desiccation. Living cells, both plant and animal, contain about 75–95 percent water. Unless the air is saturated with moisture, water readily ... | {
"Header 1": "4.1 Life on Land Imposes Unique Constraints",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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In contrast to aquatic environments, where the absorption of solar radiation by the water itself results in a distinct vertical gradient of light, the dominant factor influencing the vertical gradient of light in terrestrial environments is the absorption and reflection of solar radiation by plants. When walking into a... | {
"Header 1": "4.2 Plant Cover Influences the Vertical Distribution of Light",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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ue to the absorption and reflection of light by leaves, there is a distinct vertical gradient of light availability from the top of a plant canopy to the ground. The greater the surface area of leaves, the less light will penetrate the canopy and reach the ground. The vertical reduction, or attenuation, of light throug... | {
"Header 1": "4.2 Plant Cover Influences the Vertical Distribution of Light",
"Header 3": "QUANTIFYING ECOLOGY 4.1 Beer's Law and the Attenuation of Light",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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Soil is the medium for plant growth; the principal factor controlling the fate of water in terrestrial environments; nature's recycling system, which breaks down the waste products of plants and animals and transforms them into their basic elements; and a habitat to a diversity of animal life, from small mammals to cou... | {
"Header 1": "4.3 Soil Is the Foundation upon which All Terrestrial Life Depends",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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Soil formation begins with the weathering of rocks and their minerals. Weathering includes the mechanical destruction of rock materials into smaller particles as well as their chemical modification. **Mechanical weathering** results from the interaction of several forces. When exposed to the combined action of water, w... | {
"Header 1": "4.4 The Formation of Soil Begins with Weathering",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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Five interdependent factors are important in soil formation: parent material, climate, biotic factors, topography, and time. **Parent material** is the material from which soil develops. The original parent material could originate from the underlying bedrock; from glacial deposits (till); from sand and silt carried by... | {
"Header 1": "4.5 Soil Formation Involves Five Interrelated Factors",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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Soils are distinguished by differences in their physical and chemical properties. Physical properties include color, texture, structure, moisture, and depth. All may be highly variable from one soil to another.
Color is one of the most easily defined and useful characteristics of soil. It has little direct influence ... | {
"Header 1": "4.6 Soils Have Certain Distinguishing Physical Characteristics",
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Initially, soil develops from undifferentiated parent material. Over time, changes occur from the surface down, through the accumulation of organic matter near the surface and the downward movement of material. These changes result in the formation of horizontal layers that are differentiated by physical, chemical, and... | {
"Header 1": "4.7 The Soil Body Has Horizontal Layers or Horizons",
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If you dig into the surface layer of a soil after a soaking rain, you should discover a sharp transition between wet surface soil and the dry soil below. As rain falls on the surface, it moves into the soil by infiltration. Water moves by gravity into the open pore spaces in the soil, and the size of the soil particles... | {
"Header 1": "4.8 Moisture-Holding Capacity Is an Essential Feature of Soils",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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Chemicals within the soil dissolve into the soil water to form a solution (see Section 3.5). Referred to as exchangeable nutrients, these chemical nutrients in solution are the most readily available for uptake and use by plants (see Chapter 6). They are held in soil by the simple attraction of oppositely charged parti... | {
"Header 1": "4.9 Ion Exchange Capacity Is Important to Soil Fertility",
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Broad regional differences in geology, climate, and vegetation give rise to characteristically different soils. The broadest level of soil classification is the order. Each order has distinctive features, summarized in **Figure 4.12**, and its own distribution, mapped in **Figure 4.13**. Although a wide variety of proc... | {
"Header 1": "4.10 Basic Soil Formation Processes Produce Different Soils",
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In a report released in 1909, the U.S. Bureau of Soils stated "The soil is the one indestructible, immutable asset that the nation possesses. It is the one resource that cannot be exhausted; that cannot be used up." Yet less than three decades later, the loss of soil resources would be at the center of one of the worst... | {
"Header 1": "Ecologic al Issues & Applications",
"Header 3": "Soil Erosion Is a Threat to Agricultural Sustainability",
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In mechanical weathering, water, wind, temperature, and plants break down rock. In chemical weathering, the activity of soil organisms, the acids they produce, and rainwater break down primary minerals.
#### Soil Formation 4.5
Soil results from the interaction of five factors: parent material, climate, biotic facto... | {
"Header 1": "Ecologic al Issues & Applications",
"Header 3": "Soil Erosion Is a Threat to Agricultural Sustainability",
"token_count": 1575,
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- 5.1 Adaptations Are a Product of Natural Selection
- 5.2 Genes Are the Units of Inheritance
- 5.3 The Phenotype Is the Physical Expression of the Genotype
- 5.4 The Expression of Most Phenotypic Traits Is Affected by the Environment
- 5.5 Genetic Variation Occurs at the Level of the Population
- 5.6 Adaptation Is a P... | {
"Header 1": "Ecologic al Issues & Applications",
"Header 3": "Chapter Guide",
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"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
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Stated more precisely, **natural selection** is the differential success (survival and reproduction) of individuals within the population that results from their interaction with their environment. As outlined by Darwin, natural selection is a product of two conditions: (1) that variation occurs among individuals withi... | {
"Header 1": "5.1 Adaptations Are a Product of Natural Selection",
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By definition, adaptations are traits that are inherited—passed from parent to offspring. So to understand the evolution of adaptations, we must first understand the basis of inheritance: how characteristics are passed from parent to offspring and what forces bring about changes in those same characteristics through ti... | {
"Header 1": "5.2 Genes Are the Units of Inheritance",
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The outward appearance of an organism for a given characteristic is its **phenotype**. The phenotype is the external, observable expression of the genotype. When an individual is heterozygous, the two different alleles may produce an individual with intermediate characteristics or one allele may mask the expression of ... | {
"Header 1": "5.3 The Phenotype Is the Physical Expression of the Genotype",
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The expression of most phenotypic traits is influenced by the environment; that is to say, the phenotypic expression of the genotype is influenced by the environment. Because environmental factors themselves usually vary continuously temperature, rainfall, sunlight, level of predation, and so on—the environment can cau... | {
"Header 1": "5.4 The Expression of Most Phenotypic Traits Is Affected by the Environment",
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Adaptations are the characteristics of individual organisms—a reflection of the interaction of the genes and the environment. They are the product of natural selection. Although the process of natural selection is driven by the success or failure of individuals, the population—the collective of individuals and their al... | {
"Header 1": "5.5 Genetic Variation Occurs at the Level of the Population",
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We have defined evolution as changes in the properties of populations of organisms over the course of generations (Section 5.1). More specifically, phenotypic evolution can be defined as a change in the mean or variance of a phenotypic trait across generations as a result of changes in allele frequencies. In favoring o... | {
"Header 1": "5.6 Adaptation Is a Product of Evolution by Natural Selection",
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How does the graph in Figure 5.12b relate to this figure?
**Q2.** How do the patterns of relative fitness shown in the graphs on the left-hand column give rise to the corresponding patterns of selection illustrated by the arrows in the graphs shown in the right-hand column?
(1) shorter overall body length, (2) deep... | {
"Header 1": "5.6 Adaptation Is a Product of Evolution by Natural Selection",
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Natural selection is the only process that leads to adaptation because it is the only one in which the changes in allele frequency from one generation to the next are a product of differences in the relative fitness (survival and reproduction) of individuals in the population. Yet not all phenotypic characteristics rep... | {
"Header 1": "5.7 Several Processes Other than Natural Selection Can Function to Alter Patterns of Genetic Variation within Populations",
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The Hardy–Weinberg principle states that both allele and genotype frequencies will remain the same in successive generations of a sexually reproducing population if certain criteria are met: (1) mating is random, (2) mutations do not occur, (3) the population is large, so that genetic drift is not a significant factor,... | {
"Header 1": "5.8 Natural Selection Can Result in Genetic Differentiation",
"Header 3": "QUANTIFYING ECOLOGY 5.1 Hardy-Weinberg Principle",
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} |
The beauty of the Hardy–Weinberg principle is that it functions as a null model, where deviations from the
Figure 1 Proportion of offspring genotypes produced by heterozygous individuals mating with (a) homozygous *AA* individual, (b) another heterozygous individual, and (c) homozygous ... | {
"Header 1": "5.8 Natural Selection Can Result in Genetic Differentiation",
"Header 3": "QUANTIFYING ECOLOGY 5.1 Hardy-Weinberg Principle",
"token_count": 2004,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
These subpopulations make up **geographic isolates**, in which some extrinsic barrier—in the case of the salamanders, rivers and mountain ridges—prevents the free flow of genes
#### FIELD STUDIES Hopi Hoekstra
Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
key focu... | {
"Header 1": "5.8 Natural Selection Can Result in Genetic Differentiation",
"Header 3": "QUANTIFYING ECOLOGY 5.1 Hardy-Weinberg Principle",
"token_count": 2040,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
If Earth were one large homogeneous environment, perhaps a single phenotype, a single set of characteristics might bestow upon all living organisms the ability to survive, grow, and reproduce. But this is not the case. Environmental conditions that directly influence life vary in both space and time (Part One, The Phys... | {
"Header 1": "5.9 Adaptations Reflect Trade-offs and Constraints",
"token_count": 2010,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
In this way, the differences in beak size and diet among the three species of ground finch are magnified versions of the differences observed within a population, or among populations inhabiting different islands.
In the chapters that follow, we will examine this basic principle of trade-offs as it applies to the ada... | {
"Header 1": "5.9 Adaptations Reflect Trade-offs and Constraints",
"token_count": 267,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
For a millennia, humans have been using the process of selective breeding to modify the characteristics of plant and animal species. By selecting individuals that exhibit a desired trait, and mating them with individuals exhibiting the same trait (or traits), breeders produce populations with specific physical and beha... | {
"Header 1": "ECOLOGICAL Issues & Applications",
"Header 3": "Genetic Engineering Allows Humans to Manipulate a Species' DNA",
"token_count": 2040,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
If the phenotypic plasticity occurs during the growth and development of the individual and represents an irreversible characteristic, it is referred to as *developmental plasticity*. Reversible phenotypic changes in an individual organism in response to changing environmental conditions are referred to as *acclimation... | {
"Header 1": "ECOLOGICAL Issues & Applications",
"Header 3": "Genetic Engineering Allows Humans to Manipulate a Species' DNA",
"token_count": 2045,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
"Evaluation of the rate of evolution in natural populations of guppies (*Poecilia reticulata*.") *Science* 275:1934–1937. A beautifully designed experiment for evaluating the role of natural selection in the evolution of life history characteristics.
- Warwick, S. I., H. J. Beckie, and L. M. Hall. 2009. "Gene flow, inv... | {
"Header 1": "ECOLOGICAL Issues & Applications",
"Header 3": "Genetic Engineering Allows Humans to Manipulate a Species' DNA",
"token_count": 306,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
- 6.1 Photosynthesis Is the Conversion of Carbon Dioxide into Simple Sugars
- 6.2 The Light a Plant Receives Affects Its Photosynthetic Activity
- 6.3 Photosynthesis Involves Exchanges between the Plant and Atmosphere
- 6.4 Water Moves from the Soil, through the Plant, to the Atmosphere
- 6.5 The Process of Carbon Upta... | {
"Header 1": "ECOLOGICAL Issues & Applications",
"Header 3": "Chapter Guide",
"token_count": 788,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
**Photosynthesis** is the process by which energy from the Sun, in the form of shortwave radiation, is harnessed to drive a series of chemical reactions that result in the fixation of $CO_2$ into carbohydrates (simple sugars) and the release of oxygen $(O_2)$ as a by-product. The portion of the electromagnetic spec... | {
"Header 1": "**6.1** Photosynthesis Is the Conversion of Carbon Dioxide into Simple Sugars",
"token_count": 1452,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
Solar radiation provides the energy required to convert $CO_2$ into simple sugars. Thus, the availability of light (PAR) to the leaf directly influences the rate of photosynthesis (**Figure 6.2**). At night, in the absence of PAR, only respiration occurs and the net uptake of $CO_2$ is negative. The rate of $CO_2$... | {
"Header 1": "**6.2** The Light a Plant Receives Affects Its Photosynthetic Activity",
"token_count": 445,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
The process of photosynthesis occurs in specialized cells within the leaf called **mesophyll** cells (see Figure 6.1). For photosynthesis to take place within the mesophyll cells, CO<sub>2</sub> must move from the outside atmosphere into the leaf. In terrestrial (land) plants, CO<sub>2</sub> enters the leaf through ope... | {
"Header 1": "**6.3** Photosynthesis Involves Exchanges between the Plant and Atmosphere",
"token_count": 944,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
The force exerted outward on a cell wall by the water contained in the cell is called **turgor pressure**. The growth rate of plant cells and the efficiency of their physiological processes are highest when the cells are at maximum turgor—that is, when they are fully hydrated. When the water content of the cell decline... | {
"Header 1": "**6.4** Water Moves from the Soil, through the Plant, to the Atmosphere",
"token_count": 2024,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
The value of leaf water potential at which stomata close and net photosynthesis ceases varies among plant species (Figure 6.5) and reflects basic differences in their biochemistry, physiology, and morphology.
The rate of water loss varies with daily environmental conditions, such as humidity and temperature, and with... | {
"Header 1": "**6.4** Water Moves from the Soil, through the Plant, to the Atmosphere",
"token_count": 495,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
A major difference in $CO_2$ uptake and assimilation by aquatic autotrophs (submerged plants, algae, and phytoplankton) versus terrestrial plants is the lack of stomata in aquatic autotrophs. $CO_2$ diffuses from the atmosphere into the surface waters and is then mixed into the water column. Once dissolved, $CO_2$... | {
"Header 1": "**6.5** The Process of Carbon Uptake Differs for Aquatic and Terrestrial Autotrophs",
"token_count": 398,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
Both photosynthesis and respiration respond directly to variations in temperature (**Figure 6.6**). As temperatures rise above freezing, both photosynthesis and respiration rates increase. Initially, photosynthesis increases faster than respiration. As temperatures continue to rise, the photosynthetic rate reaches a ma... | {
"Header 1": "**6.6** Plant Temperatures Reflect Their Energy Balance with the Surrounding Environment",
"token_count": 1416,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
We have explored variation in the physical environment over Earth's surface: the salinity, depth, and flow of water; spatial and temporal patterns in climate (precipitation and temperature); variations in geology and soils (Part One). In all but the most extreme of these environments, autotrophs harness the energy of t... | {
"Header 1": "6.7 Constraints Imposed by the Physical Environment Have Resulted in a Wide Array of Plant Adaptations",
"token_count": 869,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
The amount of solar radiation reaching Earth's surface varies diurnally, seasonally, and geographically (Chapter 2, Section 2.3). However, a major factor influencing the amount of light (PAR) a plant receives is the presence of other plants through shading (see Section 4.2 and Chapter 4, Quantifying Ecology 4.1). Altho... | {
"Header 1": "6.8 Species of Plants Are Adapted to Different Light Environments",
"token_count": 2038,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
Smith, eds.), 559–596. New York: Chapman & Hall.
Kitajima, K. 2002. "Do shade-tolerant tropical tree seedlings depend longer on seed reserves?" *Functional Ecology* 16:433–444.
Myers, J. A., and Kitajima, K. 2007. "Carbohydrate storage enhances seedling shade and stress tolerance in a neotropical forest." *Journal ... | {
"Header 1": "6.8 Species of Plants Are Adapted to Different Light Environments",
"token_count": 2040,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
This calculation is performed by dividing the increment of growth during some observed time period (grams [g] weight gain) by the size of the individual at the beginning of that time period (g weight gain/total g weight at the beginning of observation period) and then dividing by the period of time to express the chang... | {
"Header 1": "6.8 Species of Plants Are Adapted to Different Light Environments",
"token_count": 1765,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
As with the light environment, a range of adaptations has evolved in terrestrial plants in response to variations in precipitation and soil moisture. As we saw in the previous discussion of transpiration (see Section 6.3), however, the demand for water is linked to temperature. As air temperature rises, the saturation ... | {
"Header 1": "6.9 The Link between Water Demand and Temperature Influences Plant Adaptations",
"token_count": 2045,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
The net result is generally a higher maximum rate of photosynthesis in C4 plants than in C3 plants.
To understand the adaptive advantage of the C4 pathway, we must go back to the trade-off in terrestrial plants between the uptake of CO2 and the loss of water through the stomata. Resulting from the higher photosynthet... | {
"Header 1": "6.9 The Link between Water Demand and Temperature Influences Plant Adaptations",
"token_count": 1793,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
As sessile organisms, terrestrial plants are subject to wide variations in temperature on a number of spatial scales and timescales. As we discussed in Chapter 2, at a continental to global scale, temperatures vary with latitude (see Section 2.2). At a local to regional scale, temperatures vary with elevation, slope, a... | {
"Header 1": "6.10 Plants Exhibit Both Acclimation and Adaptation in Response to Variations in Environmental Temperatures",
"token_count": 1607,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
Plants require a variety of chemical elements to carry out their metabolic processes and to synthesize new tissues (Table 6.1). Thus, the availability of nutrients has many direct effects on plant survival, growth, and reproduction. Some of these elements, known as **macronutrients**, are needed in large amounts. Other... | {
"Header 1": "6.11 Plants Exhibit Adaptations to Variations in Nutrient Availability",
"token_count": 2044,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
As we have seen in the preceding discussion, plant adaptations to the abiotic (physical and chemical) environment represent a fundamental trade-off between phenotypic characteristics that enable high rates of photosynthesis and plant growth in high resource/energy environments and the ability to tolerate (survive, grow... | {
"Header 1": "6.12 Plant Adaptations to the Environment Reflect a Tradeoff between Growth Rate and Tolerance",
"token_count": 804,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
In Chapter 2 we discussed that atmospheric concentrations of CO2 have been rising exponentially since the mid-19th century from preindustrial levels of approximately 280 ppm to current levels of 400 ppm (as of June 2013; Chapter 2, *Ecological Issues & Applications*). In addition to influencing the planet's energy bala... | {
"Header 1": "Ecologica l Issues & Applications",
"Header 3": "Plants Respond to Increasing Atmospheric CO2",
"token_count": 2045,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
(Data from Poorter and Pérez-Soba 2002.)
Figure 6.33 Time course of biomass enhancement ratio (BER) resulting from elevated CO2. BER is the ratio of biomass growth at elevated and ambient levels of CO2. Each line represents the results of an experiment with a different tree species. ... | {
"Header 1": "Ecologica l Issues & Applications",
"Header 3": "Plants Respond to Increasing Atmospheric CO2",
"token_count": 1908,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
Why does this occur? Based on this relationship, how do you think net photosynthesis varies over the course of the day?
- **5.** How do plants regulate the trade-off between CO2 uptake and water loss during photosynthesis?
- **6.** How does the availability of CO2 in water limit the photosynthetic rate in aquatic autot... | {
"Header 1": "Ecologica l Issues & Applications",
"Header 3": "Plants Respond to Increasing Atmospheric CO2",
"token_count": 1075,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
- 7.1 Size Imposes a Fundamental Constraint on the Evolution of Organisms
- 7.2 Animals Have Various Ways of Acquiring Energy and Nutrients
- 7.3 In Responding to Variations in the External Environment, Animals Can Be either Conformers or Regulators
- 7.4 Regulation of Internal Conditions Involves Homeostasis and Feedb... | {
"Header 1": "Ecologica l Issues & Applications",
"Header 3": "Chapter Guide",
"token_count": 538,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
Living organisms occur in a wide range of sizes (**Figure 7.1**). The smallest animals are around 2–10 micrograms [ $\mu$ g], and the largest living animals are mammals (the blue whale weighing more than 100,000 kilograms (kg) in marine environments and the African elephant at 5000 kg on land). Each taxonomic group of ... | {
"Header 1": "7.1 Size Imposes a Fundamental Constraint on the Evolution of Organisms",
"token_count": 2038,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
The diversity of potential energy sources in the form of plant and animal tissues requires an equally diverse array of physiological, morphological, and behavioral characteristics that enable animals to acquire (Figure 7.5) and assimilate these resources. There are many ways to classify animals based on the resources t... | {
"Header 1": "7.2 Animals Have Various Ways of Acquiring Energy and Nutrients",
"token_count": 201,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
Because plants and animals have different chemical compositions, the problem facing herbivores is how to convert plant tissue to animal tissue. Animals are high in fat and proteins, which they use as structural building blocks. Plants are low in proteins and high in carbohydrates—many of them in the form of cellulose a... | {
"Header 1": "7.2 Animals Have Various Ways of Acquiring Energy and Nutrients",
"Header 3": "Herbivory",
"token_count": 949,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
Omnivores feed on both plants and animals. The food habits of many omnivores vary with the seasons, stages in the life cycle, and their size and growth rate. The red fox (*Vulpes vulpes*), for
External environment
Figure 7.6 Contrast in the relationship... | {
"Header 1": "7.2 Animals Have Various Ways of Acquiring Energy and Nutrients",
"Header 3": "Omnivory",
"token_count": 392,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
Some environments change little on timescales relevant to living organisms, such as the deep waters of the oceans. However, the majority of environments on our planet vary on a wide range of timescales. Regular annual, lunar, and daily cycles (see Chapters 2 and 3) present organisms with predictable changes in environm... | {
"Header 1": "7.3 In Responding to Variations in the External Environment, Animals Can Be either Conformers or Regulators",
"token_count": 750,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
Organisms that maintain their internal environment within narrow limits need some means of regulating internal conditions relative to the external environment, including body temperature, water balance, pH, and the amounts of salts in fluids and tissues. For example, the human body must maintain internal temperatures w... | {
"Header 1": "7.4 Regulation of Internal Conditions Involves Homeostasis and Feedback",
"token_count": 2016,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
(Data from Wikelski and Thom 2000.)
Shrinkage was found to influence survival. Large adult individuals that shrank more survived longer because their foraging efficiency increased and their energy expenditure decreased (Figure 3).
Given the disadvantage of larger body size during per... | {
"Header 1": "7.4 Regulation of Internal Conditions Involves Homeostasis and Feedback",
"token_count": 726,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
Animals obtain their energy from organic compounds in the food they eat; and they do so primarily through aerobic respiration, which requires oxygen (see Section 6.1). Most organisms are oxygen regulators, maintaining their own oxygen consumption even when external (ambient) oxygen levels drop below normal. Oxygen conf... | {
"Header 1": "7.5 Animals Require Oxygen to Release Energy Contained in Food",
"token_count": 853,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
Living cells, both plant and animal, contain about 75–95 percent water. Water is essential for virtually all biochemical reactions within the body, and it functions as a medium for excreting metabolic wastes and for dissipating excess heat through evaporative cooling. For an organism to stay properly hydrated, these wa... | {
"Header 1": "7.6 Animals Maintain a Balance between the Uptake and Loss of Water",
"token_count": 1657,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
In principle, an animal's energy balance is the same as that described for a plant (see Section 6.6). Animals, however, differ significantly from plants in their thermal relations with the environment. Animals can produce significant quantities of
(a) Osmoregulation in a freshwater env... | {
"Header 1": "7.7 Animals Exchange Energy with Their Surrounding Environment",
"token_count": 672,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
Different animal species exhibit different ranges of body temperature in their natural environments. In some, body temperature varies; these species are referred to as **poikilotherms** (from the Greek *poikilos* meaning "changeable"). In others species, termed **homeotherms** (from the Greek *homoeo* meaning "same"), ... | {
"Header 1": "7.8 Animal Body Temperature Reflects Different Modes of Thermoregulation",
"token_count": 865,
"source_pdf": "datasets/websources/biochem/Smith_Smith_2015.pdf"
} |
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