Adaption/Biology Fitness
What is biological fitness
An organism's ability to survive and reproduce
The biological definition of success
What is population genetics
The area of genetics that focuses on genetic variation in the population
Requirements
More organisms are born than can survive
There is variation in the population
Organisms are different from each other, and their differences affect their fitness
Inheritance
Variation can be passed down from parent to offspring
Differences in survival and reproduction are due to variation
Isolation leads to speciation (the rise of two or more species from one existing species)
When gene flow stops between two populations, they are isolated
Over generations, changes (mutation, natural selection, or genetic drift) build up and two populations become more and more different from each other
Comparative anatomy: Homologous/Vestigial/Analogous
Homologous structures
Features that have similar origins and structure but may not perform the same function
Analogous structure
Feature that performs the same function but doesn’t level in the same way
Vestigial structures
Features that served a purpose in an ancestor species, but no longer serve a purpose in the evolved species
What is adaption
Characteristics of an organism that affect its fitness
Can be physical or behavioral
Hardy Weinberg equilibrium definition
Mathematical model that represents the frequency of alleles in a population
Pattern
Stabilizing selection
The extreme phenotype are at a disadvantage, less likely to survive
Directional selection
One extreme phenotype is favored over the rest
Disruptive selection
Two different phenotypes are favored
Divergent Evolution
Occurs when closely related species become increasingly different over time
Embryology
The study of embryos can reveal evolutionary relationships
Allele equation
p + q = 1
P - frequency of dominant allele
Q- frequency of recessive allele
Genetic Drift
Similar to natural selection, the population’s genetics change due to chance rather than due to selective pressures
The Founder Effect
A few individuals are isolated from the main population
As the founder population grows, they may not have the same amount of genetic diversity as the original population
Move to a different location by chance
Convergent Evolution
Occurs when unrelated species evolve to have similar characteristics
Molecular
Genes and proteins that are common in organisms can be used to approximate evolutionary relationship
Species that have been separated for a longer time will have accumulated a greater number of mutations
Genotype Equation
p^2 + 2pq +q^2 =1
p^2 - frequency of homozygous dominant genotype
2pq - frequency of heterozygous genotype genotype
q^2 - frequency of homozygous recessive genotype
The Bottleneck Effect
The size of a population decreases suddenly
(Natural disaster)
This can cause diversity to decrease
Co-evolution
When two species that have an ecological relationship evolve in response to each other
Can evolve to better work together or they can evolve competitively
Phylogenetic trees/phylograms
Organize living things by evolutionary steps
Often made using anatomical or molecular evidence
Animals at the ends of the tree represent organisms that have evolved
The tree shows at which points in the lineage certain traits evolved
Nodes
Where the lines intersect and represent the most recent common ancestor