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Chapter 50-Objectives
1. Explain why the field of ecology is a multidisciplinary science.
Questions from ecology form a continuum with those from other areas of biology
such as genetics, physiology, evolution, and other sciences such as chemistry, physics,
and geology.
2. 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.
3. Explain the importance of temperature, water, light, soil, and wind to living
organisms.
I already know this objective.
4. Describe how environmental changes may produce behavioral, physiological,
morphological, or adaptive responses in organisms.
Behavioral – immediate responses to unfavorable conditions in an environment
are to leave the area; some animals can modify their environments by cooperating with
nearby organisms.
Physiological – they are generally slower, but can occur rapidly if they do not
have a great effect on the rate at which certain biochemical processes occur. Most
organisms function best under fixed conditions, but some can change slightly to adapt to
their environments.
Morphological – some organisms react with reversible changes such as growing.
5. Describe the characteristics of the major biomes: tropical forest, savanna, desert,
chaparral, temperate grassland, temperate forest, taiga, tundra.
I already know this objective.
6. Using a diagram, identify the various zones found in the marine environment.
Figure 46.26
Chapter 52-Objectives
1. Define the scope of population ecology.
The scope of population ecology are density and its dispersion.
2. Distinguish between density and dispersion.
Density is the number of individuals per unit area or volume, while dispersion is
the distribution of individuals within geographical population boundaries.
3. Explain how ecologists measure density of a species.
I already know this objective.
4. Explain how age structure, generation time, and sex structure of populations can affect
population growth.
These 3 factors all affect the population growth because some species all develop,
reproduce and die at the same age. The sex ratio, if we have more females as well as
males we will have a greater population of that specie. But, if we have a low count of
females or males, we will have a lesser population.
5. Explain how age structure, generation time, and sex structure of populations can affect
population growth.
Age structure – is the relative number of individuals of each age, used to
determine rate of growth.
Generation time – the average time span between birth of individuals and the birth
of their offspring; the shorter the time in between, the greater the growth.
Sex structure – the proportion of individuals of each sex.
6. Describe the characteristics of populations which exhibit Type I, Type II, and Type III
survivorship curves.
I already know this objective.
7. Explain how density-dependent factors affect population growth.
A factor that intensifies as population growth occurs is density-dependent.
Reduced population growth rate is caused by decreased reproduction and increasing
mortality rates in a crowded population.
8. 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.
9. 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.
10. Explain how density-dependent and density-independent factors may work together
to control a population's growth.
Depending on the seasons, independent factors such as weather may affect a
population’s growth, but dependent factors are also involved because there are limited
resources left as a result of the weather for the animals.
11. List the three major characteristics of a life history and explain how each affects the:
Clutch size, frequency of reproduction, and investment in parental care.
12. Explain how predation can affect life history through natural selection.
Only the fittest can survive, so in order to survive any animal or plant must do
whatever is possible to live. This is where predators come about; they eat other plants or
animals to survive. But, at the same time they provide a balance in the environment-no
specie can overcome another specie.
Chapter 53-Objectives
1. Explain the relationship between species richness, relative abundance, and diversity.
Species richness – the number of species in a community.
Relative abundance – the population of each species in a community.
2. List four properties of a community, and explain the importance of each.
I already know this objective.
3. Explain how interspecific competition may affect community structure.
As populations of the two competing species grow, resources become more
scarce, mortality increases, birth decreases, and population growth is curtailed.
4. 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.
5. Distinguish between an organism's fundamental niche and realized niche.
Fundamental niche refers to the set of resources a population is theoretically
capable of using under ideal circumstances. The resources a population actually uses are
collectively called its realized niche.
6. Distinguish between Batesian mimicry and Mullerian mimicry.
Batesian – a harmless and palatable animal that makes itself look dangerous and
unappetizing.
Mullerian – two or more unpalatable, aposemetically colored (warning colors)
species resemble each other.
7. Explain the role of predators in community structure.
A predator is an animal o plant that consumes another plant o animal. But, it’s
good we have predators for the simple reason that they provide balance in a community,
so no specie can overcome another specie.
8. Distinguish among parasitism, mutualism, and commensalism.
Parasitism is when one organism, the parasite, harms the host.
Mutualism is when both partners benefit from the relationship.
Commensalism is when one partner benefits without significantly affecting the
other.
9. Distinguish between primary succession and secondary succession.
After an environment undergoes a natural disaster, its physical composition
changes and new species of animals may succeed older ones.
Primary – if it begins in an essentially lifeless area where soil has not yet formed.
Secondary – when an existing community has been cleared by some disturbance
that leaves the soil intact, it occurs.
Chapter 54-Objectives
1. Explain the importance of autotrophic organisms with respect to energy flow and
nutrient cycling in ecosystems.
Energy flow and chemical cycling are 2 interrelated processes that occur by the
transfer of substances through the feeding levels of ecosystems.
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2. List and describe the importance of the four consumer levels found in an ecosystem.
I already know this objective.
3. Explain how gross primary productivity is allocated by the plants in an ecosystem.
The total energy assimilated. This is the result of photosynthesis, the gross
primary productivity of most primary producers remains as net primary productivity after
their energetic needs are fulfilled.
4. Explain why productivity declines at each trophic level.
Not all energy can be consumed from one trophic level to the next, productivity
using this energy is reduced.
5. Distinguish between energy pyramids and biomass pyramids.
Energy – blocks are stacked in levels with primary producers at the bottom; size
of each is proportional to the productivity of each trophic level.
Biomass – each represents crop biomass per level.
6. Describe the carbon cycle, and explain why it is said to result from the reciprocal
processes of photosynthesis and cellular respiration.
A basic constituent of all organic compounds. Plants acquire it from the
atmosphere and they incorporate it into their own biomass through photosynthesis.
Consumed by animals and released by respiration into the atmosphere.
7. 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 is the transferring nitrogen by lightning and UV
radiation.
8. Explain how phosphorus is recycled locally in most ecosystems.
Phosphorus, which does not have an atmospheric component, tends to cycle
locally. Exact rates vary in different systems. Generally, small losses from terrestrial
systems caused by leaching are balanced by gains from the weathering of rocks. In
aquatic systems, as in terrestrial systems, phosphorus is cycled through food webs. Some
phosphorus is lost from the ecosystem because of chemical precipitation or through
settling may lock away some of the nutrient before biological processes can reclaim it.
On a much longer time scale, this phosphorus may become available to ecosystems again
through geological processes such as uplifting.
9. Describe how increased atmospheric concentrations of carbon dioxide could affect the
Earth.
The greenhouse effect (sunlight/ heat is reflected off the earth into space; CO2
reflects it back to the earth, increasing the heat on the earth.
10. Describe how human interference might alter the biosphere.
Human interference might alter the biosphere by human activities are altering
species distribution and reducing biodiversity. Human population have intruded in one
way or another into the functioning of many ecosystems. Humans have disrupted the
trophic structure, energy flow, and chemical cyling of ecosystems in most areas of the
world.
11. 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.