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
what is the estimate of total species on earth?
8 - 100 million
behavioural ecology
optimal foraging, territoriality, sex and mating systems, group living, life histories
optimal foraging theory. 3 things
1) preference for food with the highest NET energy gain
2) feed more selective when food is abundant
3) include low quality food only when food is scarce
Pied Wagtail and beetle size
When eating randomly, the pied wagtail is more likely to come across an 8mm beetle. But when the beetles get bigger their handling time increases. To maximize caloric intake per handling time the bird eats more 7mm bugs even tho they are less common.
what do terrestrial plants tend to be deficient in
sodium.. high calories
what are aquatic plants deficient in
calories.. high sodium
bison migration
have to make large migrations from their grassy areas to salt licks to get efficient sodium, cobalt, copper
- there are more predators here but they still go
rules for optimizing foraging time
1) concentrate foraging activity in the most productive patches and ignore patches of low productivity
2) stay in the patch until its profitability falls to lvl equal to all other patches combined
- -> want the highest joules/min
Bird opening lid
if the bird only took a short amount of time to open lid, might only stay a short while at the food inside (even if there was more food left)
- if the bird took a long time to open lid would stay a longer time
foraging time and predation risk
if the mouse is starving it will risk predation… if the mouse isn’t very hungry it will stay safe and not look for food
home range
the area over which an animal travels in search of food/mates/resources which is not defended
territoriality
advertisement or active defence of an area. Exclusion of resource use by others… this is common in predators
-there are different ways to mark territories
chickadees (2 types) territoriality
intraspecific territoriality but no interspecific territoriality
-different types can overlap
what influences the size of a territory
- agression
- size
- habitat quality
- population density
- competition with others
- ability to share resources
what happens when you remove some territories (ie. the great tit)
- when they removed territories… some territories got bigger, some new arrivals came
- the birds that got taken away may realize their old territory got taken and not be able to go back
cost-benefit ratio for territory size
cost: big territory takes longer to go all the way around but want enough food shelter and reproduction
asexual reproduction (cloning)
- offspring genetically identical to parent
- common in bacteria, unicellular eukaryotes
- common in plants and aquatic invertebrates
- occasionally seen in vertebrates including fish reptiles, birds and mammals
best predictor of asexual reproduction in animals?
- short lifespan
- constant environment
do asexual species ever switch to sexual reproduction?
yes.
- triggered by environmental stress
do sexual species ever switch to asexual reproduction?
- females sometimes switch following changes
e. g. no other individuals of the species encountered
parthenogenesis
a natural form of asexual reproduction
-no fertilization
dioecious
- male and female organs are on SEPARATE individuals.
- most species
monoecious
-male and female organs on the same individuals
simultaneous hermaphrodite
both sets of reproductive organs forms at the same time
- widespread in plants and inverts
sequential hermaphrodites
both sets of reproductive organs form at different times
-common in coral reef fishes
panmixis
- unrestricted random mating
- all opposite sex individuals in a population
- marine inverts, fishes
- sexes usually look alike
polygamy
multiple partners -sexes usually look different from one another TWO TYPES 1) polygyny 2) polyandry
polygyny
- many females
- males mate with many females but females only mate with single male
polyandry
- many males
- females mate with males but males mate with single female
- females are more brightly coloured than males. males will incubate eggs and become sexually inactive
- ex. many shorebird species
female defence polygyny
-individual males defend a group of females
resource defense polygyny
individual males defend resources which females seek out
monogamy
- high fidelity to a single partner
- lifetime monogamy is rare… but there are exceptions: carrion beetle, seabirds, swan, hawks, beavers, weasels, wolves
- sexes look similar
- young require extensive parental care … both parents needed!
why are females more picky in choosing a mate
- spend more time taking care of young, need fit male
- female ~ 400 eggs per lifetime where male ~ 200million sperm
how is female fitness increased
by maximizing genetic quality and genetic variability of their offspring
how is male fitness increased
by maximizing number of fertilized eggs
what are the criteria for females to pick male
1) nuptial gift
2) dominant/strong male preference
3) ‘handicapped male hypothesis’
4) parasite-free male hypothesis
5) symmetrical male hypothesis
what is nuptial gift
- males provide a ‘gift’ to the female
- females will determine male by the quality of the gift
Hanging fly nuptial gift
in hanging fly the male will bring prey to female and she will determine based on its size
-above 20mm is good
Thynnine wasp nuptial gift
- female releases pheromone which attracts the male
- for him to mate, he has to pick her up, fly with her and put her on flowers so she can feed
- if he drops her no poon
nuptial gift: songbirds
- male songbirds defend a territory
- females evaluate male based on the length and complexity of his song as this is correlated with territory size
- high quality males contribute to parental care and territorial defense
dominant/strong male presence: elephant seal
- males will fight for female
- almost every female will be able to produce offspring BUT not all males
- the top male is engaged in 90% of of kids produced each year
- only 10% of males will get a chance at mating
dragonflies do a similar thing
handicapped male hypothesis
the expression of traits that are costly to produce and costly to maintain intrigue female.
-if the male can survive with a handicap it is a signal of fitness
widowbird
- establishes a territory for females (can have more than 1)
- longer the tail the better
parasite-free male hypothesis (Hamilton and Zuk)
- males that are colourful are providing their offspring with advantageous genes that yield better resistance to disease
- bright displays are physiologically costly to produce
pigeons
- females like the brighter coloured neck pigeons
- when they have ectoparasitic lice their lustre of the feathers reduces.
- clean male has brighter colours, more likely to mate
symmetrical male hypothesis
- minor errors during embryological environment can cause asymmetry
- stress, pollutants, parasitism, homozygosity, and poor genotype as well
ex. peacock, caribou
what are genotypes that can correct asymmetries?
developmental homeostasis
display evaluation
- females evaluate quality, complexity and coordination of display
inbreeding avoidance
- all plant and animal species have one or more mechanisms to avoid inbreeding
- pheromones to detect homozygosity (many can tell based on BO)
Major histocompatibility complex (MHC)
molecules that bind and determine if homozygous or heterozygous
advantage for group living (5)
- increased food search efficiency
- increased capture efficiency
- increased detection of predators
- increased defence against predators
- selfish-herd theory (dilution effect)… individuals benefit
packsize and net kj/day
when pack size goes over 16, net kj/day goes up a lot. Catch bigger animals…. pack size from 4-16 doesn’t really change net kj/day
attack success in predators…
less likely to catch groups… greater chance of seeing predator
selfish-herd theory
each individual is looking out only for themselves
disadvantages of group living
- sharing limited resources
- increased transmission of parasites
- conflicts/stress
r-selected
- high number of eggs
- high population growth potential
- boom or bust cycle
- usually short lived
k-selected
- low number of offspring/eggs
- stable populations
- low growth potential
- usually long lived
semelparous
single reproduction
-insects, cephalopods, salmon
iteroparous
-repeated reproduction (yearly)
What animals have parental care
social insects, dinosaurs (birds), small fish, all mammals
–> parental care uncommon in many fish, amphibians, reptiles
precocial
no care
altricial
lots of care
what are 5 life histories
- r vs. K
- frequency of reproduction
- occurrence of precocial care
- clutch/litter size in k-selected species
- age of first reproduction (generation time)
clutter/litter size in K selected species
-all bird species lay fewer eggs then they are capable of doing
clutch size and the equator
- farther away from equator = higher clutch size
what happens when u artificially enlarge a clutch
CHICKS: -reduced survival in winter -reduced egg protection as adults PARENTS -reduced winter survival -reduced egg protection following year
clutch size in deer if there is no predators
- will breed every 2 years
- body weight will go down but if there are no predators it doesn’t matter
hyperdispersion
- spread out evenly
- fish schools, seabirds,
random distribution
grazing wildebeest, beach clams, forest spiders
aggregated dispersion
a) coarse grain clumps
- separated by large areas
b) fine grained clumps
- separated by short distances
What does dispersal lead to?
geneflow
what does migration lead to?
-movement of large number of individuals from one location to the next
