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Chapter Fifty
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Explain why the field of ecology is a multidisciplinary science.
Ecology is the scientific study of the interactions between organisms and
their environments. It involves using observations and experiments to test
hypothetical explanations of ecological phenomena. Examining questions
from all areas of biology as well as many physical sciences are all part of
ecology.
Describe the relationship between ecology and evolution.
Evolution can be described as a change in a population over time. Ecology
has to do with organisms and how they interact with their environment.
The fact is when a species adapts it can reproduce and continue evolving.
There is also the fact that if adapted to one environment and then placed
in a foreign one, extinction may result. Both sides affect evolution.
Explain the importance of temperature, water, light, soil, and wind to living
organisms.
 Environmental temperature affects biological processes (metabolism) and
body temperature. Water is essential for life and adaptations for water
balance and conservation help determine a species' habitat range. Sunlight
provides the energy that drives nearly all ecosystems although only
photosynthetic organisms use it directly as an energy source. Wind
amplifies the effects of temperature by increasing heat loss by evaporation
and convection. The composition of the substrate in a stream or river
greatly influences the water chemistry, which in turn influences the plants
and animals. The type of substrate influences what animals can attach or
burrow in intertidal zones.
Describe how environmental changes may produce behavioral, physiological,
morphological, or adaptive responses in organisms.
 PHYSIOLOGICAL: After several days to a few weeks the person responds
with an increased number of red blood cells being produced and when
blood vessels in the skin constrict within seconds to reduce loss of body
heat when the skin is exposed to very cold air. BEHAVIORAL: Migratory
birds migrate to warmer climates to over winter and Honeybees seal the
hive during cold periods to conserve heat and cool the hive on hot days by
the collective beating of their wings. MORPHOLOGICAL: Increase in coat
fur or feather density in winter and change in coat color between winter
and summer.
Describe the characteristics of the major biomes: tropical forest, savanna,
desert, chaparral, temperate grassland, temperate forest, taiga, and tundra.
 Tropical forest: high temperatures and heavy rainfall. Has a canopy of tall
trees with little light reaching the ground below. Savanna: grasslands with
scattered trees. High temperatures but less water then rain forests.
Desert: hot and dry (sparse rainfall) Temperate grassland: less water and
lower temperatures than savannas. Has soil rich in nutrients and mostly
called farmland. Temperate forests: (deciduous) warm summers, cold
winters, moderate precipitation. Shedding tress during winter as a form of
adaptation to poor growing conditions. Large trees with sufficient
moisture. Chaparral: dry scrubland found where winters are mild and
summers are hot and dry. Taiga: coniferous forests (i.e.- pines, firs, and
other tress with needles for leaves). Cold winters and precipitation in the
form of snow. Tundra: during winters the ground freezes. During summer,
the upper soil thaws but the deeper soil (permafrost) remains permanently
frozen.
Using a diagram, identify the various zones found in the marine environment.
Chapter Fifty- Two
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Define the scope of population ecology.
Population Ecology is the study of the growth, abundance, and distribution
of populations (density and dispersion).
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Distinguish between density and dispersion.
Population density is the number of individuals per unit area.
Population dispersion is the pattern of how individuals within a
population are spread out.
Explain how ecologists measure density of a species.
 Density = population (# of individuals) / area
Explain how age structure, generation time, and sex structure of
populations can affect population growth.
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Describe the characteristics of populations, which exhibit Type I, Type II,
and Type III survivorship curves.
 Type I: species in which most individuals survive to middle age
(humans). Type II: length of survivorship is random, like likelihood of
death is the same at any age (rodents). Type III: species in which most
individuals die young, with only a relative few surviving to reproductive
age and beyond (oysters and other species that produce free-swimming
larvae that make up a component of marine plankton).
Explain how density-dependent factors affect population growth.
 Examples of density-dependent factors are resource depletion,
competition, and predation. These effects become more intense as the
population density increases.
Describe how weather and climate can function as density-independent factors
in controlling population growth.
 Weather and climate function as density-independent factors because
they affect the population regardless of the density of the population.
Explain how density-dependent and density-independent factors may work
together to control a population's growth.
 Extreme climate may result in resource depletion making the population
struggle to survive.
List the three major characteristics of a life history and explain how each
affects the: a. Number of offspring produced by an individual b. Population's
growth
Explain how predation can affect life history through natural selection.
Distinguish between r-selected populations and K-selected populations.
 R-selected populations colonize an area that is barren or uninhabited.
They reproduce quickly to ensure their survival. K-selected populations
settle in a stabilized environment. They tend to be large animals with
long lifespans, so they produce few offsprings.
Chapter Fifty-Three
Explain the relationship between species richness, relative abundance, and
diversity.
 The species diversity within a community would be the variety of
species living close enough together for potential interaction between
the # of species (richness) and the quantity of the species (abundance).
List four properties of a community, and explain the importance of each.
 Competitive exclusion principle: when two species compete for
exactly the same resource and one species is more likely to be
successful. Resource partitioning: Species that coexist in spite of
apparent competition for the same resource (i.e.- frogs feeding on
different insects of the same pond). Character displacement: certain
individuals may obtain resources in their partitions (due to evolution
two birds with the same beaks now have slightly different beaks which
allows them to find different food to survive). Realized niche:
that part of their existence where the niche overlap is absent and they
do not compete for the same species.
Explain how interspecific competition may affect community structure.
Both population densities may increase (+ / +), one may increase while
the other decreases (+ /–), one may increase while the other is not
affected (+ / 0), or both may decrease (– / –).
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Describe the competitive exclusion principle, and explain how competitive
exclusion may affect community structure.
 The principle states that 2 species cannot coexist in the same
community if their niches are the same. This may lead to extinction of
the weaker competition or adaptation of one species to a new niche,
however it will not last long.
Distinguish between an organism's fundamental niche and realized niche.
 A fundamental niche is the resource a population is theoretically
capable of using under ideal circumstances. Biological constraints
(competition, predation, resource limitations) restrict organisms to
their realized niche: the resources a population actually uses.
Distinguish between Batesian mimicry and Mullerian mimicry.
Batesian mimicry: occurs when an animal without any special defense
mechanism mimics the coloration of an animal that does possess a
defense. Mullerian mimicry: occurs when several animals, all with
some special defense mechanism, share the same coloration.
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Explain the role of predators in community structure.
Any animal that totally or partly consumes a plant or another animal.
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Distinguish among parasitism, mutualism, and commensalism.
Parasitism is a parasite that lives on or in a host taking nourishment
from it but not killing it immediately. Mutualism co-evolve (both species
benefit). Commensalism is when one species benefits and the other is
not affected.
Distinguish between primary succession and secondary succession.
 Primary Succession: no life then there is life
Secondary Succession: there is life, then no life, then it rebuilds
Chapter Fifty-Four
Explain the importance of autotrophic organisms with respect to energy
flow and nutrient cycling in ecosystems.
List and describe the importance of the four consumer levels found in an
ecosystem.
 Producers: make their own food
Primary Consumers: eat producers
Secondary Consumers: eat producers and primary consumers
Tertiary Consumers: eat all of the above
Explain how gross primary productivity is allocated by the plants in an
ecosystem.
Explain why productivity declines at each trophic level.
 Eventually it’ll hit its K max.
Distinguish between energy pyramids and biomass pyramids.
Describe the carbon cycle, and explain why it is said to result from the
reciprocal processes of photosynthesis and cellular respiration.
 The carbon cycle is required for the building of all organic compounds.
Reservoirs: atmosphere, fossil fuels, peat, durable, organic materials.
Assimilation: plants that use carbon in photosynthesis, like when animals
consume plants or other animals. Release: plants and animals
release carbon through respiration and decomposition.
Describe the nitrogen cycle, and explain the importance of nitrogen fixation to
all living organisms.
 The nitrogen cycle is required for the manufacturing of all amino acids
and nucleic acids. Nitrogen fixation id the transferring nitrogen by
lightning and UV radiation.
Explain how phosphorus is recycled locally in most ecosystems.
 Phosphorus is recycled by: (then starts all over again)
Reservoirs: mainly rocks in which erosion transfers phosphorus to water and
soil. Sediments and rocks that accumulate on ocean floors return to the
surface as a result of lifting by geological processes. Assimilation: plants
absorb inorganic phosphorus from soils. Release: plants and animals release
phosphorus when they decompose.
Describe how the carbon cycle differs in terrestrial and aquatic systems.
Describe how increased atmospheric concentrations of carbon dioxide could
affect the Earth.
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Describe how human interference might alter the biosphere.
Human activity damages the biosphere. Exponential growth, destruction
of habitat for agriculture and mining, pollution from industry and
transportation, and many other activities all contribute to the damaging
or altering of the environment.