Midterm Study Flashcards
What is ecological genetics
genetic variability, natural selection, evolution, geological timetable… studies genetic phenotypic variability
what does a monomorphic population mean
all individuals are homozygous
what does a polymorphic population mean
if there are two or more alleles in a population
What does genetic variability originate with
a mutation: point or chromosomal. This leads to a different allele
what percentage of loci per individual are polymorphic?
5-15%
Variability
is the norm: eye colour, hair colour, skin colour etc
How does genetic variability relate to population size
little genetic variability in small populations, as population size increases so does variability
Drosophila genetic variability graph
as the population size increases, even after 500 gens 80% of the heterozygous alleles are still present, with a low now, inbred species cause the variability to die out
What does inbreeding lead to
juvenile mortality
What did the paper find about sea lions
more animals that were sick had a higher parental relatedness (homozygosity)
what is the minimum population size to maintain genetic variability in isolated populations?
2500
what does migration allow
allow for the persistence of genetic variability ~ increased survival
natural selection
non-random differential reproduction of genotypes resulting in the preservation of favourable variants
adaptation
any physiological, morphological, or behavioural modification that enhances the REPRODUCTIVE success of an organism
What are 2 ways evolution can be described
1) serial change over time
2) descent with modification
anagenesis
gradual change over time
–> does NOT lead to species diversity
cladogenesis
the branching of lineages and the formation of new species
what does cladogenesis usually occur with
geographical or genetic ISOLATION
what is the KT boundary
something that happened ~ 65 million years ago. Killed about 3/4 of earths animals. What caused dinosaurs to become extinct… between the age of reptiles (dinos) and the age of mammals.
Precambian
first hard-bodied fossil deposits. 4600 MILLION years ago
Paleozoic
beginning age of fishes. 540 MILLION years ago… first hard-body fossil deposits
mesozoic
age of reptiles. 250 million years ago
cenozoic
age of mammals. 65 million years ago
earliest life
3500-4000 million years ago