54 Flashcards
biodiversity
is the variety of life across all levels of biological organization.
genetic diversity
difference in DNA among individuals of a population
ecosystem diversity
richness and complexity of a biological community
species richness
the number of species
species evenness
relative abundance
Communities with higher diversity are:
more productive; they produce more biomass
more resistant to invasive species
better able to withstand and recover from environmental stresses
habitat
the physical location where members of the population live.
ecological niche
The totality of a species resource use, both living and non-living
Community Interactions are classified by
whether they help, harm, or have no effect on species involved
competition
-/- interaction that occurs when individuals of different species compete for a resource that limits their growth
predation
+/- interaction between species in which one species (the predator) kills and eats the other (the prey)
competitive exclusion principle
the species that acquires more of the resources will eventually “win.” The less successful species eventually dies out.
resource partitioning
Sometimes, multiple species with similar requirements coexist in the same habitat.
cryptic coloration
Cryptic coloration is a common method of avoiding detection by predators
• Cryptic coloration is prevalent in the vertebrate world.
Batesian mimicry
occurs when one species evolves to resemble a species that has superior protective capability.
Müllerian mimicry
several species that have protection against predators come to resemble each other.
parasitism
(+/-)
mutualism
(+/+)
commensalism
(+/0)
is an interaction in which an individual from one species benefits while an individual from another species is neither harmed nor helped.
– Example: Birds can make their nests in trees, and benefit from this, but generally don’t affect the trees in any way.
– “Hitchhiking species” – algae that live on the shells of aquatic turtles, barnacles that are attached to whales….
trophic structure
is the feeding relationships between organisms in a community
food chain
link trophic levels from producers to top carnivores
food web
is a branching food chain that is more complex in structure
trophic cascade (top down model)
are powerful indirect interactions that can control entire ecosystems, occurring when predators in a food web suppress the abundance or alter the behavior of their prey, thereby releasing the next lower trophic level from predation (or herbivory if the intermediate trophic level is a herbivore).
keystone species
is a species whose absence from a community would bring about significant change in that community.
primary succession
occurs on a newly exposed site, not previously occupied by soil and vegetation
example: formation of new islands, on new volcanic rock, and on land formed from glacial retreats.
secondary succession
begins in an area where soil remains after a disturbance
example: fire
Early-arriving species and later- arriving species may be linked in one of three processes:
– Facilitation: Early arrivals may facilitate appearance of later species by making the environment favorable
– Inhibition: They may inhibit establishment of later species
– Tolerance: They may tolerate later species but have no impact on their establishment
the feeding relationship among the species in a community determine the community’s
trophic structure
the principle of competitive exclusion states that
two species that have exactly the same niche cannot coexist in a community
based on the intermediate disturbance hypothesis, a community’s species diversity is increased by
moderate levels of disturbance
according to the island equilibrium model, species richness would be greatest on an island that is
large and close to a mainland
predators that are keystone species can maintain species diversity in a community if they
prey on the community’s dominant species
food chains are sometimes short because
most of the energy in a trophic level is lost as energy passes to the next higher level
which of the following could qualify as a top-down control on a grassland community
effect of grazing intensity by bison on plant species diversity
the most plausible hypothesis to explain why species richness is higher in tropical than in temperate regions is that
tropical regions generally have more available water and higher levels of solar radiation
All the organisms in a particular area make up a(n) _____.
community
According to the principle of competitive exclusion, two species cannot continue to occupy the same _____.
ecological niche
In terms of + (this member of a species pair benefits from the interaction), (this member of a species pair is harmed by the interaction), and 0 (this member of a species pair is unaffected by the interaction), predation can be described as a _______ relationship.
+/-
The term used to describe a harmless organism resembling a harmful one is __________.
Batesian mimicry
The ecological relationship between termites and the wood-digesting protozoans that live in their gut is an example of _____.
mutualism
If the larvae (juvenile offspring) of a particular species of mosquito are to survive to the adult stage, the eggs must be laid in the trapped pool of water of the northern pitcher plant. The mosquito larvae provide no apparent benefit or harm to the pitcher plant. This type of interaction is an example of _____.
commensalism
An organism’s “trophic level” refers to _____.
what it eats
Keystone species are those species _____.
whose absence would cause major disruption in an ecosystem
Which of the following best illustrates ecological succession?
Grass grows on a sand dune, then shrubs, and then trees.
During ecological succession, the species composition of a plant community _____.
changes gradually because each species responds differently to changes in environmental factors
_______ views a community as the chance assemblage of organisms with similar abiotic needs.
The individualistic hypothesis
When goats were introduced to an island off the California coast, the goats lived in the same areas and ate the same plants as the native deer. The deer population dwindled and finally disappeared. This is an example of _____.
competitive exclusion
The niche of an animal is _____.
the way the animal fits into its environment
Two species of cuckoo doves live in a group of islands off the coast of New Guinea. Of 33 islands, 14 have one species, 6 have the other, 13 have neither, and none has both. What might best explain this? The two species of birds could ______.
have similar niches
Under which of the following circumstances would interspecific competition be most obvious?
when a foreign organism is introduced to a community
If the niches of two species are very similar, which one of the following is true?
Competition between the two species will be severe.
What type of population interaction benefits neither population?
competition
Flounder look like the sea floor. This is an example of _____.
cryptic coloration
Which of the following is an example of mimicry?
A harmless frog resembles a poisonous frog.
A tick has what type of relationship with a dog?
parasitic
The flower fly resembles a honeybee, but the flower fly has no stinger. This is an example of _____.
Batesian mimicry
The poison-arrow frogs (genus Dendrobates) of tropical America are all brightly colored and have very similar patterns. Each species is distasteful to predators and all possess toxic skin secretions, although some of the species live quite separate from the others. The adaptive relationship among these species is best termed _____.
Müllerian mimicry
The term used to describe bold coloration in harmful species (such as the coral snake) is _____.
warning coloration
Lichen is actually composed of two organisms: a fungus and an alga. They depend on each other for survival. The most specific term that describes their relationship is _____.
mutualism
Certain species of acacia trees in Central and South America have hollow thorns that house stinging ants, which attack anything that touches the tree. The ants feed on nutrients produced by the acacias. This is an example of _____.
mutualism
The relationship between species A and species B is described as commensalism. This means that _____.
one species benefits and the other species is unaffected
Which of the following is a primary producer?
poison ivy
When you eat an apple, you are a _____.
primary consumer
In Paine’s study of the intertidal zone on the coast of Washington State, he found that _____.
the presence of a keystone predator maintained community diversity
A species of malaria-carrying mosquito lives in a forest in which two species of monkeys, A and B, coexist. Species A is immune to malaria, but species B is not. The malaria-carrying mosquito is the chief food for a particular kind of bird in the forest. If all these birds were suddenly eliminated by hunters, which of the following would be an immediately observable consequence?
increased mortality in monkey species B
After clear-cutting, timber companies cannot afford to wait for the long process of _____ to occur naturally; they plant trees right away.
succession
The current view of succession is _____.
that disturbance and nonequilibrium are inevitable
Succession of communities occurs because _____.
each existing community changes the environment
The study of the geographic distribution of species is called __________.
biogeography
True of False: All keystone species are also apex predators.
false. Keystone species are often predators, but not always apex predators. Instead, they are usually secondary consumers. Sea stars, while voracious predators of mussels and barnacles, for example, are a prey species for sea anemones and fishes.
resource partitioning
The concept of resource partitioning, as originally developed, relates to evolutionary change in species in response to selection pressures generated by interspecific competition.
