Download AP Biology Name Chapter 41 Reading Guide: Species Interactions

AP Biology
Chapter 41 Reading Guide: Species Interactions
Name ____________________
Describe in your own Words the Key concepts of Chapter 41
 Interactions within a community may help, harm, or have no effect on the species involved
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Diversity and trophic structure characterize biological communities.
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Disturbance influences species diversity and composition
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Biogeographic factors affect community diversity
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Pathogens alter community structure locally and globally
1. Distinguish between intraspecific competition and interspecific competition. Give an
example of each.
Interspecific- Interactions with individuals of other species in the community.
Intraspecific- Interactions whereby members of the same species compete for limited resources
2. Explain G. F. Gause’s principle of Competitive Exclusion and the experiment that supports it.
Two species competing for the same limiting resources cannot coexist permanently in the same
place. When there is competition for the same resources, one species will be at an advantage
and this will lead to a slight reproductive advantage, which will eventually cause the local
elimination of the inferior competitor.
3. Define Ecological Niche. How can two species use resource partitioning to coexist despite the
competitive exclusion principle?
An ecological niche is the specific set of biotic and abiotic resources that an organism uses in its
environment. Resource partitioning enables similar species within a community to occupy
different ecological niches and therefore allow two similar species to survive.
4. What is the difference between a fundamental niche and a realized niche?
Fundamental Niche- the niche potentially occupied by that species
Realized Niche- the portion of the fundamental niche that it actually occupies in a particular
environment.
5. Explain Character displacement. (use the terms allopatric and sympatric in your explanation)
Closely related species whose populations are sometimes allopatric (geographically separate)
and sometimes sympatric (geographically overlapping). In some cases, the allopatric populations
of such species are morphologically similar and use similar resources. By contrast sympatric
populations, which would potentially compete for resources, show differences in body
structures and in the resources they use. This tendency for characteristics to diverge more in
sympatric than in allopatric populations of two species is called character displacement.
6. List three special adaptations that predators use to capture their prey, and three adaptations
that prey use to avoid predators.
Predators often develop acute senses that enable them to find potential prey. They also develop
weaponry in the form of sharp teeth, claws, or poison to help them catch and subdue their prey.
Predators are often fast and agile if they are apt to chase their prey, or well camouflaged if they
ambush their prey.
Prey often utilize cryptic coloration (camoflauge) to avoid predators. Some animals accumulate
toxins from their food and then utilize aposematic coloration to warn predators. They also use
various types of mimicry to confuse predators.
7. Explain the difference between Batesian and Müllerian mimicry.
Batesian Mimicry- when a palatable or harmless species mimics an unpalatable or harmful one
Müllerian Mimicry- Two or more unpalatable species resemble each other
8. List 2 adaptations that herbivores use for predation, and two adaptations of plants to avoid
herbivory.
Herbivores also develop various senses to determine what plants are safe and healthy to eat.
They may also have specialized teeth or digestive systems to process vegetation.
Plants may utilize chemical toxins or strucutres like spines and thorns to ward away herbivores.
9. Define parasitism and explain the differences between Endoparasites and ectoparasites. Provide
an example of each.
Endoparasites- Parasites that live within the body of their host, Such as tapeworms
Ectoparasites- Parasites that feed on the external surface of a host, such as ticks or lice.
10. Define Mutualism and give an example of it. Explain the difference between mutualism and
commensalism.
Mutualism is an interspecific interaction that benefits both species (+/+). This could include
nitrogen fixation by bacteria in the root nodules of legumes or cellulose digestion by
microorganisms in the digestive systems of mammals.
11. Explain the two components of Species Diversity.
Species Richness- The number of different species in a community
Relative abundance- The proportion each species represents of all individuals in the community.
12. What is the Shannon Diversity Index?
The Shannon Diversity index is a tool used to calculate indexes of diversity based on species
richness and relative abundance.
H = - (pa ln pa + pB ln pB + pc ln pB +…)
13. What is Biomass?
The total mass of all individuals in a population
14. Describe the general Trophic Structure and transfer of energy in a community
The transfer of food energy up the trophic levels from its source. Primary producers > Primary
consumers > Secondary consumers > Tertiary consumers > Quarternary consumers >
Decomposers
15. Compare and contrast Dominant species, Keystone Species, and Foundation species.
Dominant species - species that are the most abundant or that collectively have the highest
biomass
Keystone species - not the dominant species but have a strong control on community structure
with their ecological niches
Foundation species - species that dramatically alter their environment
16. What is the difference between a bottom-up model and a top-down model? How do scientists
use the top-down model to improve water quality in polluted lakes?
The bottom up model postulates an unidirectional influence from lower to higher trophic levels
N>V>H>P.
The top up model postulates the opposite: predation mainly controls the community
organization because predators limit herbivores, herbivores limit plants, and plants limit
nutrients. N<V<H<P.
Ecologists have applied the top down model through biomanipulation to attempt to prevent
algae blooms to improve water quality in polluted lakes by altering the density of higher-level
consumers instead of using chemical treatment.
17. What is a disturbance? Explain the intermediate disturbance hypothesis.
An event that changes a community by removing organisms from it or altering resource
availability. The intermediate disturbance hypothesis states that moderate levels of disturbance
foster greater species diversity than do low or high levels of disturbance.
18. What is the difference between primary succession and secondary succession?
Primary succession - when ecological succession occurs in a virtually lifeless area where soil has
not yet formed
Secondary succession - when an existing community has been cleared by some disturbance that
leaves soil intact
19. What is the strongest agent of disturbance today?
Human activity
20. What two factors affect latitudinal gradients of species richness and how do they?
Evolutionary history and climate. Over the course of evolutionary time, species richness may
increase in a community as more speciation events occur. Climate can affect the growing
seasons in ecosystems so that biological time essentially runs faster.
21. What is demonstrated by a species area curve?
A species-area curve demonstrates that, all other factors being equal, the larger the geographic
area of a community, the more species it has.
22. What two physical features of an “island” affect immigration and extinction rates?
Its size and its distance from the mainland.
23. Why do small islands have lower immigration rates? Higher extinction rates?
Small islands generally have lower immigration rates because potential colonists are less likely
to reach it. Small islands also generally contain fewer resources and less diverse habitats and
smaller populations so the populations are very susceptible to certain environmental changes.
24. Explain MacArthur and Wilson’s Island Equilibrium Model.
MacArthur and Wilson argue that equilibrium will eventually be reached where the rate of
species of immigration equals the rate of species extinction.
25. What is a pathogen? What Is a Zoonotic Pathogen?
Pathogens are disease causing organisms and viruses. A Zoonotic Pathogen is a pathogen that is
transferred to humans from other animals.
26. What is a vector? Give three examples of vectors.
A vector is an intermediate species that spread zoonotic diseases. Vectors are often parasites
such as lice, ticks, or mosquitoes.