Download Chapter 41 Reading Guide: Species Interactions

Chapter 41 Reading Guide: Species Interactions
41.1 Interactions within a community may help harm, of have no effect on the
species involved
Define the following terms…
Community:
Interspecific Interactions:
Interspecific competition:
Competitive exclusion:
Ecological Niche:
Resource partitioning:
Character displacement:
Predation:
.
Herbivory:
Symbiosis:
Parasitism:
Mutualism:
Commensalism:
Facilitation:
List five examples of Interspecific Interactions
Describe how the symbols + and – are used to indicate interactions
What was Gause’s experiment and what did he conclude?
Explain the connection between a species fundamental niche vs. its realized niche.
Explain the difference between allopatric populations (geographically separate) and sympatric
populations (geographically overlapping).
What are some examples of morphological and physical defense adaptations that prey develop?
What adaptations do herbivores have that allow them to survive the way they do?
Why do changes in either species of mutualism affect the survival and reproduction of the other?
41.2 Diversity and tropic structure characterize biological communities
Define the following terms…
Species Diversity:
Species Richness:
Relative Abundance:
Biomass:
Invasive Species:
Tropic Structure:
Bottom-up Model:
Top down Model:
Biomanipulation:
What are the components of species diversity?
Explain the Shannon Diversity index. Write the equation, meanings of each variable and it’s use.
What are the five advantages to having a more diverse community?
Explain trophic structure in terms of primary producers, primary consumers, secondary consumers,
tertiary consumers and quaternary consumers (you may make a diagram if that’s helpful to you)
Draw an example of a food web
How do Dominant, Keystone species and ecosystem engineers impact their community?
41.3 Disturbance influences species diversity and composition
Define the following terms….
Disturbance:
High level disturbance:
Intermediate disturbance hypothesis:
Ecological succession:
Primary succession:
Secondary succession:
Compare the “balance of nature” view to the nonequilibrium model.
Balance of nature: The view that biological systems are at equilibrium unless seriously disturbed
by human activities. They were stable, or have a relatively constant composition of species.
Nonequilibrium: current model of thinking, describes most communities as constantly changing
after disturbance
How is an intermediate level of disturbance good for species diversity?
High levels of disturbance create high levels of stresses so that certain species may not survive.
Low levels of disturbance allow competitively dominant species to exclude less competitive ones.
But moderate levels of disturbance open up habitats for less competitive species.
How can large disturbances be important for an ecosystem?
Some ecosystems are dependent on large disturbances. The pinecones of trees in Yellowstone do
not open unless exposed to the intense heat of forest fires.
Describe the process of primary succession.
Only life forms initially present are prokaryotes and protists then lichens and mosses are
commonly the first colonizers. Soil develops gradually and then lichens and moss are overgrown
by grasses, shrubs and trees. Then its colonized by plants that become the primary vegetation.
This may take hundreds of thousands of years.
Describe the three possible links between early and late arriving species.



Early arrivals may facilitate the appearance of later species by making the environment
more favorable
Early species may inhibit that arrival of later species so that colonization happens in spite
of the actions of early species
Later species tolerate the independent actions of the initial species
41.4 Biogeographic Factors affect community diversity
Define the following termsEvapotranspiration: the evaporation of water from soil and plants together (a function of solar radiation temperature, and
water availability is higher in hot areas with abundant rainfall)
Potential evapotranspiration: a measure of water loss that assumes that water is readily available (determined by amount of
solar radiation and temperature and is highest in regions where both are plentiful.
Island Equilibrium model: The idea that an equilibrium on an island will eventually be reached where rate of species extinction
equals immigration.
What are two biogeographical features in particular that contribute to the range of diversity in a
community?
The latitude of a community, and the area it occupies.
What did Darwin and Wallace point out that was later confirmed by current researchers?
Plant and animal life was more generally abundant and diverse in the tropics than other parts of
the globe
What are the two key factors affecting latitudinal gradients of a species?
Evolutionary history and climate
Why is species diversity greater in tropical regions than in temperate Polar Regions?
Because of their longer evolutionary history and the greater solar energy input and water
availability in tropical regions.
Explain the species-area curve
All other factors being equal, the larger geographical area of a community the more species it
has.
What are two factors that determine the number of species on the island?
The rate at which new species immigrate to the island and rate at which species become extinct
Explain the relationship between total species and extinction and immigration rate on an island.
As the number of species on the island increases, immigration decreases because any individual
reaching the island is less likely to represent a species not already present. Extinction rates
increase as well because of the greater likely hood of competitive exclusion.
What are two physical features on an island that affect immigration and extinction rates?
Size (smaller islands generally have lower immigration rates because potential colonizers are less
likely to reach a small one than a larger one), and distance from the mainland (closer island will
have more immigration rates)
41.5 Pathogens alter community structure locally and globally
Define the following termsPathogens: disease causing organisms and viruses
Zoonotic pathogens: those that are transferred from humans to other animals
How are zoonotic pathogens transferred?
Through direct contact with an infected animal or by means of an intermediate species called a
vector (parasites including ticks, lice, or mosquitos)
Give an example of how pathogens can affect the structure of a community
In the forests and savannas of California, trees of several species are dying from sudden oak d