Lesson 7: Macroevolution

Question 1

Macroevolution

Answer 1

Large scale and long term evolutionary patterns among many species
—influenced by microevolutionary mechanisms
—deals with more than one species

Question 2

Adaptive radiation

Answer 2

the diversification of a common ancestral species into a range of species, each of which has a unique environmental adaptation; this process is known as divergent evolution since each of the succeeding species evolved from a single common ancestor.

Question 3

How adaptive radiation works

Answer 3

When a species’ population grows to a point where it may invade nearby regions.
–The population of new species increases and spreads to nearby environments; speciation reoccurs when the new populations have adapted to their new habitats and food niches. Migratory populations adapt to their new home and leave behind their original speciation.

Question 4

Convergent evolution

Answer 4

The Evolutionary process in which similar traits arise in two or more species because e/ species has independently adapted to similar environmental conditions
no common ancestor involved

Question 5

Convergent evolution- example

Answer 5

Birds, butterflies and bats evolved independently and evolved different types of wings. BUT, natural selection favored variations suitable to the same environment—the sky.

Question 6

Co-evolution

Answer 6

When two organisms that are closely linked to each other gradually evolve together

Question 7

Co-evolution- example: predator/prey

Answer 7

As prey develop better defenses (longer faster legs, harder shell, better camouflage) predators develop better killing traits (stronger claws, sharper and harder teeth, more lethal venom, stronger jaws)

Question 8

Gradualism p1

Answer 8

Evolution change occurs generation (w/n a lineage) slowly and steadily before and after a divergence
-large evolutionary change are the result of the accumulation of many small changes
-proposed and accepted during Darwin’s time

Question 9

Gradualism p2

Answer 9

-however it’s difficult to verify in the fossils records
-fossil records showed that species are often relatively short lived (20000 years) and appear and disappear suddenly
-some longer-lived species have remained relatively unchanged for millions of yrs

Question 10

Punctuated equilibrium

Answer 10

-Proposed by Niles Eldredge and Stephen Jay should in the 1980s–> evolutionary change consists of long periods of stasis broken up by periods of divergence.
—most species will undergo most of their changes when they first diverge from their species. Relatively nothing changes after this.
-sudden, substantial changes in the environment cause episodes of divergence