Lesson 1: Introduction to Evolutionary Biology (sir ppt) Flashcards
Why study evolution?
- understanding its process is highly relevant to human health
- extends and amplifies the explanation of biological phenomena
highly relevant to human health
understanding the processes of evolution
understanding the processes of evolution helps us understand:
- infectious disease outbreaks
- antimicrobial resistance
fascilitates the spread of drug resistance
gene transfer
what are proximate causes
immediate, mechanical causes
ultimate causes of phenomena
historical causes, especially the action of natural selection
“Nothing in biology makes sense except in the light of evolution.”
Theodosius Dobzhansky (1900-1975)
what is evolution
increase in fitness over time due to natural selection, or adaptation
alters fitness over time
mutations
- refers to how common an allele is in a population
- heritable expression of those alleles
allele frequencies
group of organisms that consist of similar individuals capable of interbreeding or exchanging genes among themselves
species
defines a species taxon as a group of organisms that can successfully interbreed and produce fertile offspring
Biological Species Concept
helped define the modern synthesis of evolutionary theory, proposing the “Biological Species Concept.”
Ernst Mayr
can reproduce
viable offspring
cannot reproduce
sterile offspring
- descent with inherited modification
- transmission of traits that increase chance of survival
Biological evolution
fitness vs adaptation
adaptation - traits
fitness - measure of reproductive success
- measures of reproductive success of a species
- produce viable offspring
- allow continuous passing of genes
fitness
heritable change in the expression of alleles
epigenetic inheritance
group of interbreeding individuals and their offspring
population
Five major mechanisms of evolution
- genetic drift
- mutation
- heritable epigenetic modification
- migration
- natural selection
totally random changes in allele frequency from generation to generation
genetic drift
changes in the genetic code, such as errors in DNA replication, gene deletions or duplications, etc
mutation
heritable changes that arenot due to changes in DNA sequence itself, but the expression of the DNA
epigenetic inheritance
example of changes in epigenetic inheritance
DNA methylation and histone modifications
what do epigenetic inheritance change
epi-allele not actual alleles (genetic code)
alleles moving from one population to another
gene flow (migration)
- when some alleles favored over others due to an increase in fitness (not random)
- acts on genetic variation in the population
natural selection