Biology 100 Unit 14 Flashcards
is the study of major biological changes seen in the fossil record (i.e., obvious structural differences).
macroevolution
When changes accumulate to produce a completely distinct group of organisms, we call this ___________.
speciation
-This includes the origin of a new species (speciation).
According to the ______________________, a species is a group of members in a population with the potential to interbreed and produce fertile offspring.
Biological Species concept
According to the biological species concept a species is a
group of members in a population with the potential to interbreed and produce fertile offspring.
Members of different species don’t mate due to
reproductive isolation.
The biological species concept can be problematic. – Some pairs of clearly distinct species occasionally
interbreed and produce _____________.
hybrids
– For example, grizzly bears and polar bears may interbreed and produce hybrids called ____________.
groolarbears
_________________may bring these two bear species together more frequently and produce more hybrids in the wild.
– These 2 distinct species would not be reproductively isolated from each other, therefore difficult to classify as _______________________
– Alternate species concepts can be useful.
Melting sea ice
distinct species.
Another species definition is the __________________ ____________, which identifies species in terms of their ecological niche, looking at their role in an community.
ecological species definition
The ecological species concept
focuses on unique adaptations to particular roles in a
biological community.
or example, two species may be similar in appearance but distinguishable based on
- what they eat
- where they live
Lastly, the ___________________defines a species as the smallest group of individuals that share a common ancestor, forming a branch on an evolutionary tree.
phylogenetic species concept
Biologists trace the phylogenetic history of a species by comparing its
DNA sequences
Alternate ways of defining species using physical traits, shape, size or other features.
Morphological species concept
Give two examples of the morphological species concept
- asexual organisms
- fossils
prevent interbreeding and establish different species.
reproductive barriers
What do reproductive barriers do
the isolate gene pool
barriers prevent mating between different species.
prezgotic or postzygotic
Generally fertile offspring are the result
of the same species mating, with few exceptions.