Macroevolution Flashcards
What is macroevolution?
Evolution above the species level. Includes large scale evolutionary trends and things like the origins of major groups
What is gradualism?
Large phenotypic differences evolve through many slightly different intermediate states
What is punctuated equilibrium?
Rapid evolutionary changes separated by periods of stasis
Is the earliest fossil of a group the actual origin of the group?
No, the group always originated before the first fossil
Do calculated rates of change in the fossil record underestimate or overestimate the maximum rate of evolutionary change?
Underestimate
Why is the maximum rate of evolutionary change always underestimated in the fossil record?
We only have so many fossils, and measurements are made over a long period of time
What unit is used for the rate of evolution?
Darwins
Does a shorter or larger interval of time have faster rates of evolutionary change?
Shorter. Longer periods of time have a larger underestimation
Do living fossils have lower rates of genetic change than other species?
No
What does the fossil record show about the rates of skeletal changes in lungfishes?
300 million years ago was undergoing rapid changes, then rate of change dropped significantly after 250-200 million years
What does a lower rate of change mean for how long a genus lasts?
A genus lasts for much longer
What is an evolutionary trend?
Persistent, directional change in the average value of a trait in a clade over time
What are the two types of evolutionary trends?
Passive and active
What is a passive evolutionary trend?
A slower trend that has no force acting on it
What is an active evolutionary trend?
A trend that has a force acting on that trait to push it in one direction
