2.4 Organisms and Evolution: Sex and Behaviour Flashcards
2.4 (22 cards)
why are eggs much larger and fewer in numbers?
due to their energy store
why is a greater investment made by females?
due to fewer and larger gamete
what else can be said about females?
their chances of reproductive success is lower and chance of passing on genes is reduced
if parent investment is costly then why does it happen?
increases the chances of survival of young
describe the type of offspring produced in a stable environment:
smaller rather ‘expensive’ young with extensive parental care
describe the type of offspring produced in an unstable environment:
many ‘cheaper’ young with little energy or parental investment provided
what is meant by an r-selected population?
tends to occur in unstable environments, offspring tend to be produced in large quantities, and there tends to be little to no parental investment and short lifespan
what is a K-selected population?
tends to occur in stable environments, offspring tend to be produced in smaller quantities and tends to be extensive parental care and a longer lifespan
what internal fertilisation?
when the sperm and egg nuclei fuse inside the female
what external fertilisation?
when the sperm and egg nuclei fuse outside the female
what is meant by monogamous?
one male mating with one female
what is meant by polygamy?
polygyny and polyandry
what is meant by polygyny?
when one male mates exclusively with a group of females
what is meant by polyandry?
when one female mates with several males during breeding season
How can successful courtship behaviour in birds and fish occur?
species-specific sign stimuli that trigger fixed action pattern responses
What does sexual selection favour in individuals?
favours traits that may provide little or no survival advantage but increase an individual’s chances of mating
(bright plumage or elaborate displays)
what is sexual dimorphism?
the physical differences between males and females of a species
what is reversed sexual dimorphism?
when the female is more conspicuous
e.g. when the female is bigger than the male
what is female choice?
females assessing honest signals of the fitness of males
what is lekking?
males gather to display at a lek, where female choice occurs
what is meant by sneaking?
male that gains access to mate with females without more dominant male knowing
what is a satellite male?
male that sneaks to gain access to mate with a female
