natural selection Flashcards
the two men associated with fitness in natural selection
Charles Darwin and Alfred Wallace
what are two ways nature is significant in terms of fitness?
- adapts species to a changing environment
- selects from variable populations the most “fit individual”
fitness measures what?
reproductive success
how are traits determined by fitness?
transmissible by biological inheritance
is the determination of fitness species-limited ?
yes
how can we determine if an animal is adapted to its environment?
by its physicality and behavior and if it survives
if an animal is highly adapted to a specialized environment, what is needed?
genetic variability
what happens when there is population loss
lack of genetic variation and there was a too sudden change in the environment (ex. timidness)
behavior considered typical of a population may be changed by what?
- genetic selection
- learning and social tradition
define and provide an example of social inheritance
- what the offspring learns from parental generation
ex. farmers poisoned lamb caracasses and coyotes learned to avoid them and only eat live lambs
what are the necessities that shape behavior? true or false: a successful animal will have more of one of these traits than the other
food
shelter
mates
avoiding predation
false: a successful animal will have balanced behaviors
what happens when there is an explosive population
there won’t be enough resources for species
true or false: if there is a stable population they’re in optimum conditions
true
are starvation, disease, predation the only limiting factors for population growth?
no, the behavior phenomena as well
what is territorial regulation and provide an example
animal defends its area of living, aggressive acts directed against other members of the same species and sex which trespass
ex. marking territory by spraying or scratching a tree
which gender is more likely to show territoriality?
males
what are the benefits of territoriality?
- increased probability of successful reproduction
- reduced predation
- adequate food supply
which animals are territoriality not common in?
domesticated hoofed animals
name and define the types of space
- home range- larger than territory, area which animal learns thoroughly in which habitually uses, not defended, can overlap
- territory- defends area by fighting or demarcation and other individuals detect it and serves as a deterrent
- individual space- minimal distance animal preserves for itself
why may there be a reduction in male breeding success in feral populations?
- low social status
- competition in polygynous species
what is the difference between polygamy and polyandry?
polyandry is strictly females mating with several males and not vice versa
why is the difference in male status not an important regulator in population size?
one male can mate with many females
why is low social status of females important in controlling population size?
litter bearers, low ranking females can be forced out of the pack or not allowed to mate
crowding leads to _____?
stress
define stress
physiological changes that reduce reproductive capacity
define self preservation
animal sustains itself, to cope reproduction decreases
what happens when there is an increase in population density where it is crowded?
population and production decrease, more injury
define secondary sexual dimorphism
males and females have different looks, morphology, body presence differs depending on sex
which species exhibit or lack secondary dimorphism
mammalian and avian
how does dimorphism attract females and why?
- males are larger, more colorful, weapons
- males compete with other males to breed with females
define ungulates
hoofed mammal
define gallinaceous
domestic fowl
Compare ethograms of species with marked secondary sexual dimorphism and those without
marked dimorphism
- live in large social groups
- don’t typically pair bond
- lots of females and one or two breeding males, well organized social groups
- breeding males possess harems (polygyny)
- young are precocial (don’t need as much parental care, developed at birth)
- horses
lacking dimorphism
- live in nuclear family unit
- pair bonding of male and female
- young are altricial
- cats., dogs, primates
what species are the exception to dimorphism
ducks and geese
why do differences exist in sexually dimorphic species?
males compete for females, so to be successful breeding they have to be competitive to pass on their genes
why do males in polygynous, dimorphic species dominate other males?
they produce more offspring and that male gets the advantage
list the function of males
inseminate females
litter care of young
expendable (as dominate male starts to age, younger males try to knock him off and take his place)
what is the purpose of females
fitness = the ability to provide adequate care of young
which sex has a larger lifespan and why
females because they bear the offspring and don’t have the responsibility of protecting and fighting
why is instinctive behavior controversial?
genes vs environment
- implies behavior is entirely controlled by genetics
define innate behavior
increases fitness and occurs in adequate form when first needed
define behavior patterns
combination of innate and learned components
what are examples of behavior patterns
- characteristic movements of newborn mammals to locate mammary gland
- suckle
- swallow
- distress call of lost
- isolate neonatal
define innate releasing mechanism (IRM)
hypothetical mechanism that is selectively sensitive to release stimuli for a particular instinctive action
example of innate releasing mechanism
piglet knows to suck on teat
how does a primate take care of her young when she is isolated
maternal behavior is lost because studies show that primate maternal behavior is learned
