2.4 Sex and Behaviour Flashcards
number of gametes produced by males
large
number of gametes produced by females
small
size of energy store in males gametes
small
size of energy store in female gametes
large
who invests the most when it comes to parental investment in most species
females
females invest in…
the egg structure in non-mammals or in the uterus during gestation in mammals
parental investment is
costly but increases the probability of production and survival of young
what can parental behaviour be classified into
r-selected species and k-selected species
what are r-selected species
smaller organisms that usually produce larger numbers of offspring, providing no parental care, having shorter life spans and have a lower offspring survival probability
what are k-selected species
larger organisms that usually produce lower numbers of offspring, providing more extensive parental care, have longer life spans and have a high offspring survival probability
where does r-selection tend to occur
in unstable environments where the species has not reached its reproductive capacity
where does k-selection tend to occur
in stable environments
what is internal fertilisation
the process by which the sperm and egg nuclei fuse inside the female
what is external fertilisation
the process by which teh sperm and egg nuclei fuse outside the female
benefits of internal fertilisation
increased chance of successful fertilisation
fewer eggs needed
offspring can be retained internally for protection and/or development
higher offspring survival rate
costs of internal fertilisation
a mate must be located which requires energy expenditure
requires direct transfer of gametes from one partner to another
benefits of external fertilisation
very large numbers of offspring can be produced