Ecological Genetics Flashcards
What is ecological genetics/genomics?
- the study of genetic/phenotypic variability in natural populations of plants and animals and the relationship to ecological processes
oikos
house, a place to live
_____ is to _____ as physics is to engineering
ecology, environmental science
what is deep ecology
totality of all ecosystems
what is community ecology
all the species of plants and animals living in same place at the same time
what is population ecology
group of conspecific indviduals living in same place at the same time
T/F: variability within natural populations is uncommon
false, variability is the norm
what does a monomorphic population mean?
all individuals are homozygous (aa, both alleles are the same)
what does a polymorphic population mean
if there are two or more alleles in a population (ab), an individual is a heterozygote
what does genetic variability originate with?
a mutation - point and chromosomal which leads to a different allele
what % of loci per individual are polymorphic?
5-15%
roughly how many genes does an individual have?
20,000 genes / individual
can a locus gene have many alleles?
yes, can have many within a population (a,b,c,e, etc) but each individual can have a max of 2 for a diploid species
how does genetic variability relate to population size?
little genetic variability in small populations, as population size increases so does variability
describe the drosophila genetic variability graph
as the population size increases, even after 500 generations 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 did the study on drosophila measure?
the amount of variation remaining in the population over time in relation to the original population size
what was the approx fraction of initial genetic variation after 500 generations when (dros study)…
N= 1000
N= 300
N= 100
N= 20
- 0.85
- 0.45
- 0.15
- 0.00 (extinct after 200 generations)
what happened to rocky mountain bighorn sheep after 50 years?
went extinct due to homozygosity, unable to cope with pathogens, parasites, disease and led to death
what is the min population size to maintain genetic variability in isolated populations?
2500
T/F: increased numbers of individuals results in increased inbreeding
false - reduced numbers of individuals result in increased inbreeding
does inbreeding influence the response of california sea lions to different pathogens in the wild?
yes, increased homozygosity leads to increased pathogen related death
what is the minimum viable population (MVP)
the population must retain 90% of variability of 200 years. MVP depends on habitat area and species requirements. MVP for an isolated population is ~2500
what is minimum viable area (MVA)
minimum land required to retain 90% genetic variability over 200 years
population size is dependent on
area of habitat
how big is the most common park size?
15km^2
large carnivores require how much km^2?
~100,000km^2, no parks are that large. small amount of immigration can allow populations to survive in areas >MVA
how can variability still persist in park populations
immigration
what does small amount of migration per generation from other populations allow for
persistence of genetic variability and increased survivial
what # of immigrants per generation was needed to maintain 90% genetic variability after 100 generations in drosophila?
2
what is natural selection
non-random and differential reproduction of genotypes resulting in preservation of favourable variants
what is an example of natural selection
genotype AB has higher survivorship or higher reproductive output than genotype AA
what is adaptation
any physiological, morphological, or behavioural modification that enhances survival and reproductive success of an organism
Reimchen did a study on snails. there where two phenotypes, a yellow snail and a brown snail. looking down, it was very difficult to see the brown snail but the yellow one stood out, making it easy for predators to see. why did both phenotypes persist?
the yellow snail could not be seen from below, and the brown one stood out
what are 2 ways evolution can be described
- serial change over time
- descent with modifcation
what is anagenesis?
a type of evolution, gradual change over time. Does not lead to species diversity, leads to adaptation
what does anagenesis lead to
adaptation
what is cladogenesis?
a type of evolution, the branching of lineages and formation of new species. leads to the formation of a new species
what does cladogenesis lead to?
the formation of a new species
what does cladogenesis usually occur with?
geographical or genetic isolation
what is the KT boundary?
something that happened ~65 mill years ago. Killed about 3/4 of earths animals and is what caused dinosaurs to become extinct. Between the age of reptiles and the age of mammals
precambian
first hard bodied fossil deposits, occurred 4600 million years ago
paleozoic
first fossils from hard shells marks beginning (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
what is the estimate of total species on earth?
8-100 million
