Evolution Flashcards
What is lamarckian evolution?
Acquired characteristics are passed on to next gen
Ex: giraffes have long necks because they stretched them to get leaves from trees and developed long necks.
What is the theory of natural selection?
Individuals in a population exhibit heritable variation passed from generation to generation. Some individuals have varying reproductive success, with some having advantageous traits that allow for better survival.
Organisms compete for resources and adapt to conditions as the environment changes.
What is directional selection?
An extreme population is selected for in the original population and the evolved population shifts toward that extreme
What is disruptive evolution?
Both extreme populations are selected from the original population so the evolved population only has the two extremes and the common population is eliminated
What is stabilizing selection?
Common population is selected for from the original population and the evolved population becomes the common selection
What is some evidence of plant evolution?
Fossil records, evolutionary mosaics, biogeography, homology, biochemical data
What is homology?
Similarity due to common ancestory
What are homologous structures?
Anatomical resemblances that represent variation from a common ancestor
What is phylogeny?
Evolutionary history of a species or group of related species
What is taxonomy?
The ordered division and naming of organisms
What is a monophyletic group?
It includes the ancestor and all descendants
What is a paraphyletic group?
It includes the ancestor but not all descendants
(How birds aren’t included in reptiles because they are so different)
What is a polyphyletic group?
There are no common ancestors
(Similar features but not related)
What is a clade?
A group of species that includes an ancestral species and all it’s descendants
What is a synapomorphy?
A trait that evolved in a common ancestor and all descendants inherited it.
(Derived)
What is a symplesiomorphy?
A trait found in a common ancestor but also found in other distantly related groups
(Ancestral)
What is convergent evolution?
Evolution of similar features in distantly related groups. Found when groups adapt independently to their environment in a similar way
(Adapted similarly to environmental but not related)
What is allopatric speciation?
When a population forms a new species while geographically isolated from parent population
What is sympatric speciation?
When a sunset of a population forms a new species without geologic separation
What is a polyploid?
A species that contains 3 or more sets of chromosomes. Can give rise to sympatric speciation
What causes polyploidy?
When homologous chromosomes fail to separate during meiosis producing diploid gametes.
When two diploids come together they create a polyploid
