*macroevolution Flashcards
An organisms ability to multiply depend largely on what?
- availability of resources (food, water, shelter, and space).
- as population size increases, access to resources decreases, and the environment will ultimately prove inadequate.
Define adaptive radiation
a process in which organisms diversify rapidly into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges and opens environmental niches.
A species, or group of species, will diverge into as many variations as two factors will allow. what 2 factors?
1) its adaptive potential
2) the adaptive opportunities of the available niches
The rapid expansion of placental mammals during the late Mesozoic and throughout the Cenozoic(hominids) is an example of what?
adaptive radiation
Why was the worldwide major extinction event at the end of the Cenozoic a good thing for small-bodied, mostly nocturnal mammals?
The extinction left thousand of eco niches vacant as the dinosaurs became extinct, with no competition the small mammals were free to move into the previously occupied habitats.
-example of major adaptive radiation
Explain generalized characteristics and specialized characteristics
these two terms refer to the adaptive potential of a particular trait.
- a trait that’s adapted for many functions is said to be generalized.
- one that’s limited to a narrow set of functions is said to be specialized.