Evolution- Darwin And The Modern Synthesis Flashcards
Define transmutation of species
Altering of one species into another
How did finches adapt to different habitats
Different beaks
Outline Thomas Malthus Populations
Populations have tremendous growth potential but resources are limited
Define fitness
The differential survival and reproduction of individuals due to differences in phenotype
Outline Darwin’s 4 theories for natural selection
-Individuals within species are variable because of mutations in DNA creating new alleles and subsequent shuffling of alleles
-some of the variations are passed on to offspring- genes/alleles are passed on to offspring in fact and often independently of other genes
-in most generations, more offspring are produced than can survive
-survival and reproduction are not random: individuals with the highest reproductive success are those with the most favourable variations with alleles and allelic combinations that best adapt them to their environment - they are ‘naturally selected’
Define evolution
Terms of changes in allele and gene frequencies over time
Define altruistic behaviour
No. Survival or reproductive advantage to the adult- eg, parents feeding child
Define altruism
Selection operation on alleles in relation to their average contribution to their own transmission through their action on the individuals that carry them
-the same alleles will be present in close relatives
Outline the assumptions of the HW equilibrium
(If an allele population is not in HW)
-no sex linkage
-random mating
-mutations does not occur
-migration is negligible
-population size is large
-no selection
-there is no consanguinity
What is HW used for
Used to predict the number of each genotype/allele frequencies from the allele/genotype frequencies
What is the HW equation
P^2+2PQ+Q^2=1
P=dominant
Q= recessive
Define the founder effect
The loss of genetic variation that occurs when a new population is established by a very small number of individuals
Define genetic bottlenecks
A sharp reduction in the size of a population over several generations
How do prokaryotes differ from eukaryotic evolution
-chromosomes -> singular circular DNA (haploid)
-plasmids-> occur naturally, important in antibiotic resistance
Defined conjugation
Plasmids can pass between different species by horizontal gene transfer through a sex pilus
Define transformation regarding prokaryotes
Bacteria can take up free DNA and integrate into their genome
Define transduction regarding prokaryotes
Transfer of DNA through phases (virus of bacteria)
When does an allele have a selective advantage
When it makes the organism possessing it more likely to survive and reproduce
Definition of an allele
Alternative version of an allele
Outline genetic drifts for small populations
By chance an allele could be transmitted to a high proportion of offspring: if an allele is lost- it’s extinguished (other allele is fixed)
Outline genetic drifts for large populations
Allele frequencies change more slowly
