INTRASPECIFIC RELATIONSHIP (part 2)
BREEDING BEHAVIOUR
behaviours associated with breeding (courtship) are adaptations to ensure reproductive success
breeding pairs often establish territories to ensure reliable access to resources during breeding
ritualised courtship behaviours reduce conflict between sexes so that mating can be achieved without injury
courtship behaviour
behaviour of animals occurs just before, during and after mating
a potential mate can be attracted by a call, or by offering a gift of food
females often choose their mates as females have more invested in offspring, so mate choice is important
intersexual selection occurs when members of the same sex choose mates of the other sex to mate with
reproductive effort
the amount of energy used for reproduction, including production and care of young
generally, the amount of energy remained after production will be allocated to parental care
at one extreme, all of the reproductive effort is put on production and hence no parental care
low percentage of offspring survive
broadcast spawners release millions of gametes into the water and very few planktonic larvae will survive
at another extreme, most of the reproductive effort is put on parental care of a small number of offsprings
high percentage of offspring will survive
mammals have high level of parental investment in offsprings before and after birth
bird parents incubate their eggs in a nest and then feed the chicks until they are independent
amphibians, fishes and reptiles also provide care until the offsprings are capable of fending themselves
MATING SYSTEM AND PARENTAL CARE
polygynandry
polygyny
monogamy
polyandry
the breeding pair forms a partnership
shared care improves survival of youngs, especially when the environment becomes harsh
both parents look after the young
multiple mating takes place between group member
all group members contribute to the care of young
increase genetic diversity
decrease male competition for mates
females mate with more than one male
females gain nutritional benefit when males provide prenuptial gifts
males may care for their own offspring and females leave the males
males control access to more than one female
the best and strongest male is selected
provide the offspring the best gene
males often show parental care after mating and leave it to the female
TERRITORIES
TERRITORIAL BEHAVIOUR
Territories are small areas where are defended by aggressive behaviour
The behaviour that an organism will defend aggressively for its nesting site
Advantages
reduce direct competition between large number of individuals
provide access to rich food source
provide a safe and secure place to rear youngs
increase the offspring chance of survival from predators
provide a safe place to court
enhance reproductive success
costly in terms of time and energy exerted
where the organisms need for successful breeding
dividing resources between groups or individuals
rich resources for exclusive access
strong individuals more likely to own big territories
better protection
more likely to attract mates and breed
pass on strong genes to the offsprings
more likely to get access rich food source
Yellowhead territories
occupied by cooperating individuals which helps to support breeding pair
each breeding group contains primary pair that breed, and secondary birds acting as nesting helpers but not breeding (e.g. provide additional food for the clutch)
HOME RANGES
the area where animals roam but is not defended
may overlap with other home ranges
home ranges in baboons
each home range has its own population
spend nearly all day travelling in search of food, but still returns to safe core area before dusk to sleep
most activities concentrate in core area where contain best food source, water holes and trees for sleeping
home ranges in Karearea
reproductive success is higher in commercial pine forests with a mixed of different aged status than in native forests
prey availability is enhanced in pine plantation
home ranges are larger when resources are scare
the home range size in the pine forest is much smaller than that in native forest