2.4.1 sex and behaviour; parental investment Flashcards
when is female investment high for non mammals
in relation to the egg structure
when is female investment high for mammals
in the uterus or during gestation
what is the con of parental investment
it is costly
what is the benefit of parental investment
increases the probability of production and survival of young
how can r selected and k selected organisms be classified
based on level of parental investment in offspring and the number of offspring produced
what are characteristics of r selected species
smaller
shorter generation time
mature more rapidly
reproduce earlier in their lifetime, often only once
produce a large number of smaller offspring, each of which receiving only a small energy input
limited parental care
most will not reach adulthood
what are characteristics of k selected species
larger and live longer
mature more slowly
can reproduce many times in their life
produce relatively few, and larger offspring
high level of parental care
many have a high probability of surviving to adulthood
when does r selection tend to occur
in unstable environments where the species has not reached its reproductive capacity
when does k selection tend to occur
in stable environments
what are the benefits of external fertilisation
large numbers of offspring can be produced
what are the costs of external fertilisation
many gametes are predated or not fertilised
no or limited parental care
few offspring survive
what are the benefits of internal fertilisation
increased chance of successful fertilisation
fewer eggs needed
offspring can be retained internally for protection and development
higher offspring survival rate
what are the costs of internal fertilisation
a mate must be located, which requires energy expenditure
requires the direct transfer of gametes from one partner to another
