Sex & Evolution Flashcards
(24 cards)
what is present or true of asexual reproduction
a genetically identical offspring
a pea hen (female peacock) is described as ___ when mating
choosey
definition of intrasexual
male to male competition
what is batsman’s principal
female choosiness
natural selection in birds
beak size and shape
polyandry
more than one husband
what is an example of bateman principle
ancestral women typically could now have dramatically increased their reproductive output but adding more sex partners
when given a choice, as opposed to a stable internal predisposition, a female animal engages in sexual behaviour with another female. this is an example of an individuals:
sexual preference
name some environmental cues for sex determination in animals
temperature (crocodiles and turtles) -
available nutrients, water availability, photoperiod it time of year, competitive stress, pheromones from conspecifics
what aminals do not use environmental sex determination?
mammals and birds
what is sexual reproduction?
process of developing a genetically unique individual
what is asexual reproduction
a single parent generates offspring that are genetically identical
asexual reproduction is characterized by the absence of three sexual reproductive factors:
meiosis, reduction in ploidy (pairing of chromosomes or number of chromosomes) and the fusion of gametes
types of asexual reproduction: (3)
budding (portion of the parent buds out and goes off on its own and develops into a fully functioning organism fully attached to the parent and then breaks off
— common in vertebrates and small organisms in the sea
fragmentation (parent individual breaks off a piece of itself and then later develops into its own individual
—starfish, flatworm
parthenogenesis (develop a gamete without fertilization
— virgin births
how is sex expensive?
the cost of meiosis to generate a haploid gamete or cells (reproducing individuals that cannot reproduce on their own
the cost of finding a mate (sexual displays and rituals are energy, time and resource expensive)
what is the advantage to reproducing sexually?
more diverse gene pool protection, resource gathering, social organization to benefit from groups and being together
describe muller ratchet theory
the process which in the absence of genetic recombination (a sexual reproduction has this because there is no combination of genes - the genes come from one parent) this results in a accumulation of irreversible deleterious mutations eventually leading to the extinction of the population
describe the red queen hypothesis
unique genetic composition within a species offers environmental adaption
—defence against parasites
sexual reproduction offers the opportunity for continued development to maintain evolutionary “fitness”
in other words, evolution is a race and the environment is filled with competition (viruses, parasites, different challenges to species) it’s continuously updating itself or it’s doomed
what is evolution?
it is the biological changes in a process of descent with modification
adaptions to their changing environments resulting in changes genes, new traits and new species
difference between microevolution and macroevolution
micro: studies changes at the DNA level or allele level
macro: studies large scale changes like the evolution of a new species which is the process of numerous microecolutionary changes
competition vs choosiness
males compete for access to females
female soften choose among many males according to the males anatomical features of behaviours
what is Batemans principal and how does it relate to competition vs choosiness
Female should be choosy, because female candies are more expensive (we are born with all of our eggs while males generates sperm through spermatogenesis)
female reproductive success is limited
intrasexual vs intersexual
intra: competition within one sec for access to members of the opposite sex (two-males competing)
inter: choosey females choosing their male partner
what are sexual dimorphisms? name an example
the difference in size and appearance between sexes of the same species
male deer have antlers while females don’t
