LECTURE 24 - Individuals, Behaviours and their environment Flashcards
coping mechanism
Coping mechanism = Morphology + physiology+ behaviour
difference between morphology, physiology and behaviour
Morphology : teeth, skull, guts,
Physiology : e.g. capacity to digest plant cell wall in grass
Behaviour : foraging strategies, social behaviour, communication
Fitness def
Fitness – an individual’s relative contribution to the next generation’s gene pool
significance of behaviour, ecologically and evolutionary
ecologically:
- the link between individuals and environment
- affects population outcomes
- affects interactions among species
evolutionary:
- genetic basis (nature vs nurture)
- affects fitness
behaviour related to abiotic/biotic enviro
Behaviour in relation to:
Abiotic environemnt (temperature etc) : morphological adaptations to cope with temperature
Biotic environment (predator etc) : escape/defend, forage, win/choose mates
behaviour 3 key aspects
1) obtain food
2) avoid being food
3) reproduc
obtaining food : behaviour
- Foraging : camoflague to ambush or agile/fast to hunt down prey
a. Defined by what they eat (carnivore, frugivore), how they get it (active vs ambush), and diet breath (generalist vs specialist)
optimal forgaing theory/marginal value theorem
So, the optimal foraging theory helps animals decide what to eat, and the marginal value theorem helps them figure out when it’s time to leave one food patch and find a new one. This way, animals can make sure they get the most energy from their food while using their time and effort wisely.
optimal foraging theory
modelled which food items to eat in a non-depleting environment
* predicts foragers should maximise net rate of food (= energy) intake
ME : Optimal foraging theory suggests that animals should try to eat food that gives them the most energy for the least amount of effort.
Food Patch
A food patch is like a buffet table for animals. It’s an area where there’s a bunch of the same type of food. In our bird example, a food patch might be a big bush full of juicy berries. Imagine you’re at a buffet with lots of your favorite food, like pizza, fried chicken, and dessert. When you first start eating, the food is fresh and delicious. But as more people serve themselves, the quality of the food starts to decrease. The pizza gets cold, the fried chicken dries out, and the dessert runs out. So, when should you decide to leave the buffet?
Marginal Value Theorem
modelled when to leave a food patch in a depleting
environment
* predicts that foragers should leave food patches when
capture/harvest rate at patch < average capture/harvest rate
ME: if the bird has already picked most of the best berries and only the small, not-so-yummy ones are left, it should fly off to find a new food patch with better berries. For animals, this means they leave a patch of food when what they can catch or harvest there is less than what they usually get on average.
avoid being food : behaviour
Avoid being eaten : eaten = zero fitness
run away, group together to intimidate predators, hide:
- Act costly (look dangerous or toxic to predator)
- be costly (have spikes, release poison)
- feed in safe places or times
–> however feeding in safe places only, misses opportunites to forage elsewhere, or more competition (but benefits is not dying so benefits > cost)
reproduce : behavior
- Courtship & mating behaviour: non-random
- Parental care
- Trade-off costs versus benefits?
- Male-male (♂-♂) competition
- Female (♀) choice, sexual selection
* Results in non-random mating (& non-random offspring)
ME : peacock tail
* High costs of such a tail
(think energy in production & maintenance; risk of predation)
–>need very high benefits to outweigh costs
* benefits? access to mates (♀ behaviour: choosy about mates)
* Darwin hypothesised: ♂ peacock tail arises from natural selection,
via selective pressure associated with sexual reproduction
intrasexual selection
males compete with each other for access to the other sex (females). In many animal species, males often compete to be chosen as mates by females.
This competition can take various forms, such as physical combat, displays, or other behaviors aimed at gaining an advantage in mating opportunities.
intrasexual dimorphism : observable differences that can result from intrasexual competition. e.g stronger
sexual dimorphism
Sexual dimorphism refers to the differences in physical characteristics between males and females of a species.
intersexual selection
females choose their mates based on certain traits or characteristics displayed by the other sex (often males).
sexual dimorphism : For example, if females prefer mates with flashy or ornate traits, males in the population may evolve to exhibit these characteristics to attract females. This results in a contrast between flashy (often males) and plain (often females) individuals in the species.
