Unit 2 KA4 Flashcards
(a)
In what way is there greater investment by females in parental investment
- egg structure vs sperm
- in most species the female is the most involved parent in the bringing up of offspring
a
why is parental investment beneficial?
costly but increases probability of production and survival of young
a
r-strategists
definition and characteristics
definition-organisms with low parental investment
characteristics
* smaller * shorter gestation time * mature more rapidly * reproduce earlier in their lifetime * limited parental care * large number of offspring
a
K-strategists
definition and characteristics
definition- organisms that give higher level of parental care
characteristics-
* larger offspring
* higher chance of survival to adulthood
* mature slowly, few offspring
a
What enviroment does r-selection usually occurs in compared to K-selected?
unstable, where species has not reached its reproductive capacity compared to stable in K
a
benefits and costs of external fertilisation
benefits
* very large numbers of offspring can be produced
costs
* many gametes are predated or are not fertilised
* limited/no parental care
* few offspring survive
a
benefits and costs of internal fertilisation
benefits
* increased chance of successful fertilisation
* fewer eggs needed
* retained internally for prodection
* higher survival rate
costs
* mate must be located, requires high energy expenditure
* requires direct transfer of gametes from one partner to another
b
monogamy
the mating of a pair of animals to the exclusion of all others
b
polygamy
umbrella term for where individuals of one sex have more than one mate
b
polygyny
type of polygamy
one male mates exclusively with a group of females
b
polyandry
type of polygamy
one female mates with a number of males in the same breeding season
b
what can a successful courtship behaviour in birds and fish be a result of?
species-specific sign stimuli
fixed action pattern responses
b
what characteristics does sexual selection select for?
what would make a female more likely to pick a male?
characteristics that have little survival benefit for the individual but increase chance of mating
b
what can be a product of sexual selection
sexual dimorphism
where females are inconspicuous and males are more conspicuous in markings structures and behaviours
b
reverse sexual dimporphism
where females are more conspicuous than males
b
what does female choice involve?
females assessing honest signals of finess of males
b
what can honest signals indicate?
favourable alleles that increase chances of survival of offspring
low parasite burden suggesting a healthy individual
b
what happens in lekking species for female choice to occur?
males gather to display at a lek
(dominant males in the centre)
satillite males avoid conflict and are on the fringes
b
success in male-male rivalry through conflict increases what?
access to females for mating
