evolution test Flashcards
Darwin inferred that all organisms descended from a…
common ancestor
What is evolution?
A gradual change in heritable traits over time
Individuals in a population show variation due to what 2 things?
Mutation and meiosis
What is competition?
Two animals trying to access the same limited resources
What’s another name for natural selection?
Survival of the fittest
What is fitness?
The ability of an organism to survive in its environment and mate successfully
What is stabilizing selection?
When the moderate trait is favored over the two extremes
What is disruptive selection?
When the two extreme traits are favored over the moderate trait
What is directional selection?
When one extreme is favored over the other
Who else came up with natural selection besides Darwin?
Alfred Wallace
Genetic drift is a change in…
allele frequencies
T/F: Genetic drift is complete luck/chance
True
What is the founder effect?
When a small proportion of a population establishes a new population with a different allele frequency
What is the bottleneck effect?
When a small proportion of the original population survives, causing a sudden change in allele frequency
What four processes are involved in natural selection?
-Genetic variation
-Overproduction of offspring
-Struggle for existence
-Differential survival and reproduction
What are the 5 types of evidence used to prove evolution?
-Vestigial structures
-Anatomical evidence
-Molecular evidence
-Embryological evidence
-Fossil evidence
What is speciation?
The formation of new and distinct species in the course of evolution?
A hybrid is a cross between…
different species
What causes speciation to occur?
When populations are reproductively isolated
What are the two types of speciation?
Allopatric and sympatric
What are prezygotic barriers?
Barriers that occur before zygote formation (they prevent successful mating)
What are examples of prezygotic barriers
-Behavioral isolation
-Gametic isolation
-Temporal isolation
-Habitat isolation
-Mechanical isolation
What are postzygotic barriers?
Barriers that occur after a zygote has formed
If two different species interbreed and have a zygote, what can cause problems?
The chromosomal mismatch
What problems can chromosomal mismatches cause?
-It could be lethal to the embryo
-Can result in an unhealthy individual
-The embryo is infertile
What is allopatric speciation?
When populations of species become geographically isolated
What is sympatric isolation?
When speciation occurs without geographical isolation
What else can speciation cause?
Extinction
What else can cause extinction?
-New diseases
-New, successful competitors
-New predators
-A single catastrophic event
-A change in the environment
What type of population is most vulnerable of genetic drift?
Small populations
What is strata?
Rock layers that scientists study to observe evolution
What are sudden changes in the rock strata called?
catastrophism
What is Uniformitarianism?
Geological processes have changed the shape of Earth
What is gradualism?
The idea that species originate through a gradual change of adaptations
What is punctuated equillibrium
When speciation occurs quickly, in rapid bursts with long periods of genetic equilibrium in between
What is adaptive radiation?
a number of different species diverge from a common ancestor
What is convergent evolution?
evolution among different groups of organisms living in similar environments produces species that are similar in appearance and behavior
What is taxonomy?
The science of naming organisms and assigning them to groups
What are the classifications in taxonomy?
Kingdom
Phylum
Class
Order
Family
Genus
Species
