Mechanisms of Speciation
Describe microevolution
Microevolution is the change in the gene pool of a population from one generation to the next
The study of fossils provides strong evidence for ?
evolution
The offspring of pairs of clearly distinct species are called
hybrids
Which species concepts could you apply to both asexual and sexual species? Explain.
The morphological, ecological, and phylogenetic species concepts could all be used because they do not rely on the criterion of reproductive isolation.
Describe habitat isolation and whether this is a prezygotic or a postzygotic barrier
-lack of opportunities to encounter each other/different habitats
-prezygotic
? is the process by which one species splits into two or more species, accounts for both the unity and diversity of life
Speciation
How does microevolution differ from speciation
Microevolution involves evolutionary changes within a population; speciation occurs when a population changes enough that it diverges from its parent species and becomes a new species.
The morphological species concept is
observable physical traits and can be applied to asexual organisms and fossils.
? prevents mating or fertilization between species.
prezygotic barriers
Describe temporal isolation and whether this is a prezygotic or a postzygotic barrier
-breeding at different times/seasons
-pre
Adaptations are often compromises, explain why:
Each organism must do many different things. A blue-footed booby uses its webbed feet to swim after prey in the ocean, but these same feet make for clumsy travel on land.
what is a species defined as
It defines a species as a group of populations whose members have the potential to interbreed in nature and produce fertile offspring (offspring that themselves can reproduce).
The ? species concept defines a species by its niche and focuses on unique adaptations to particular roles in a biological community.
ecological
? barriers operate after hybrid zygotes have formed.
Postzygotic
Describe behavioral isolation and whether this is a prezygotic or a postzygotic barrier
-different courtship or rituals
-pre
Evolution is limited by historical constraints, explain:
Evolution doesn't build each new complex structure from scratch. Rather, it co-opts existing structures and adapts them to new situations. Ex: birds and bats evolved from four-legged ancestors, their existing forelimbs took on new functions for flight and each lineage was left with only two limbs for walking.
Which of the following best measures an organism’s fitness?
how many fertile offspring it produces
how strong it is when pitted against others of its species
its ability to withstand environmental extremes
how much food it is able to make or obtain
how many fertile offspring it produces
The phylogenetic species concept is defined as?
species as the smallest group of individuals that share a common ancestor and thus form one branch of the tree of life
Describe reduced hybrid vitality and whether this is a prezygotic or a postzygotic barrier
-reduced hybrid vitality (hybrid development or survival impairment by interaction of parental genes)
-post
Describe mechanical isolation and whether this is a prezygotic or a postzygotic barrier
-physically incompatible reproductive parts
-pre
Humans owe much of their physical versatility and athleticism to their flexible limbs and joints. But we are prone to sprains, torn ligaments, and dislocations. Why?
Adaptations are compromises: Structural reinforcement has been compromised as agility was selected for.
The existence of barriers that stop members of two species from producing viable, fertile offspring with each other is called
reproductive barriers/isolation
two species of fish may be similar in appearance but distinguishable based on what they eat or the depth of water in which they are usually found this is an example of:
ecological species concept
Describe reduced hybrid fertility and whether this is a prezygotic or a postzygotic barrier
-vigorous hybrids that can't produce viable offspring
-post
Describe gamete isolation and whether this is a prezygotic or a postzygotic barrier
-incompatible gametes/molecular incompatibility
-pre