Lec 6: Natural Selection and Early Life Flashcards
What is biological evolution? What are 2 words that sum it up?
What is it driven by?
The gradual change in the inherited traits of a population. It is about survival and reproduction. Driven by variation in reproductive success
What were the 2 ideas established by Darwin?
1) That all species on Earth may have evolved from one species.
2) Natural selection
What was Lamarck’s theory?
Lamarck argued for the inheritance of acquired traits. This would mean that if an individual acquires a trait during their lifetime, their offspring can inherit it.
Is natural selection based on phenotype or genotype selection?
phenotype selection (expression of trait)
Define a gene and an allele
gene: DNA unit on a specific spot of the chromosome, determines a particular characteristic
allele: a variant form of a given gene
In gene vocabulary, what does biological evolution mean?
Change in allele frequencies in a population over time.
What is fitness?
reproductive success! (how good are you at making babies)
What are the 2 ways genetics can vary?
through mutation or mode of reproduction
What is mutation?
a mistake in the gene replication
How do prokaryotes reproduce?
through binary fission, the replication of the circular chromosome followed by the fissioning of the cell
Besides binary fission, what are other ways that genetic information can be transmitted in prokaryotes?
- conjugation: sharing plasmids
- transformation: picking up plasmid from environment
- transduction: virus relocates DNA
Is genetic material organized into chromosomes in prokaryotes?
no
Which 2 processes during meiosis increase genetic variation?
reassortment and recombination
What is the advantage of eukaryotic sexual reproduction?
It generates a lot of variation
What are the 5 consequences of eukaryotic sexual reproduction?
1) mate searching costs
- if the population is small, this can be a huge cost. the probability of finding a mate is small, thus sustaining population size is difficult.
2) Competition
Competition due to sexual reproduction causes behavioral effects
3) Display costs
4) Only 1/2 the population generates offspring
5) Good gene combinations are broken apart
