lecture 5 Flashcards
Who proposed the main models of Diversity of Life that changed over time?
Darwin
What is the difference between Typological Theory and Theory of Evolution?
Typological Theory- unchanging+variations do not matter
Theory of Evolution-changing + variations matter
**what evolves ?
populations evolve, individuals do not
What 2 discoveries help demonstrate the vast changes through time? How?
fossil record and sedimentary rocks
What did these lead to the creation of?
geological time scale
extinct
no longer exists
Transitional Features
transitional are changing traits
vestigial Traits
no longer have function
homologies
similar traits amongst species due to having a common ancestor
Homology can be studied at what 3 levels?
- genetic
- developmental
- structural
what were Darwins 4 postulates?
- variations exist
- heritability
3.survival+reproduce success vary - best traits that increase survival or reproductions get passed down
fitness
ability to produce surviving fertile offspring
adaptation
a trait that increases fitness
selection
best traits passed onto next generations
What are 3 common misconceptions about evolution…and what is the reality?
- does not change individuals
- it it not goal oriented
- does not create perfection
What is the source behind evolution (aka where is variation occurring)?
alleles
What are the 4 processes that drive changes in allele frequencies
- natural selection- best traits passed down
- genetic drift- chance event kills or prevents reproduction of part of population
- gene flow- organisms leave or enter population
- mutations- adds new alleles or traits
How does Natural Selection affect allele frequencies?
alleles that contribute to reproductive success get passed on
How does genetic drift affect allele frequencies?
causes allele frequencies to change randomly, especially in small populations
How does gene flow affect allele frequencies?
individuals leave one population enter another and breed
How does mutations affect allele frequencies?
continually creating new alleles
How does the Hardy-Weinberg Principle become useful in all of this?
gave us ways to analyze these allele frequencies + genotype frequencies
