Ecology - Week 9 Flashcards
What two requirements are required in order for a behaviour to be an adaptation?
- be heritable
- increase fitness in the current environment
What is a proximate answer?
the immediate, mechanistic cause of a phenomenon (answering the question of how it happens)
- deals with the immediate mechanisms resulting in a trait (how did this particular instance of the trait come to be?)
What is an ultimate answer?
the reason that a trait is thought to have evolved (why it happens)
- deals with larger scale, long-term mechanisms resulting in the trait (why does this trait (in general) exist?)
What is aggression?
an example of behaviour that can have heritable basis
alleles that affect neural tube development → reduced brain size → low aggression
What is indirect fitness?
individuals can pass on their alleles to the next generation by producing their own offspring AND by helping close relatives produce more offspring
- help each other, some risk
- help your relatives, some risk
What are reproductive cheaters?
benefit, no risk
What is reproductive cooperation?
help each other, some risk
How is cooperation maintained?
- give individuals a reason to cooperate (create opportunities for reciprocity, identify as one time and maintain trust, make sure everyone has a chance to win)
- give individuals a reason not to defect (punish cheaters, make others aware of what is at risk)
What are intraspecific interactions?
interactions within a single species (between conspecifics)
What are conspecifics?
members of the same species
What are the 3 intraspecific interactions?
- cooperative (+/+)
- competitive (-/-)
- exploitative (+/-): cheating
What are interspecific interactions?
interactions between species (between heterospecifics)
What are heterospecifics?
members of different species
What are the 3 interspecific interactions?
- mutualistic (+/+)
- competitive (-/-)
- exploitative (+/-): parasitism and predation
What is parasitism?
where the parasite lives on or in another organism (host), which results in some harm
What is predation?
where the predator kills and eats another organism (prey)
What does + mean?
What does - mean?
What does 0 mean?
+: increases fitness
- : decreases fitness
0: no effect on fitness
What is commensalism?
(+/0)
What is ammensalism?
(-/0)
What are neutral interactions?
(0/0)
interactions that have little or no effect on fitness of either party
- will generally be less important in the context adaptations and community dynamics
How are species interactions classified?
according to how the interaction impacts the fitness of both parties
- if we only measure the fitness of one party, we can’t know for sure what type of interaction is going on
ie. if we observe that an interaction increases the fitness of one party (ie. living inside a sea anemone increases the fitness of the clownfish), we still won’t know whether we are observing a case of mutualism, commensalism, or parasitism/predation
How can we explain the distribution of species?
- dispersal
- abiotic factors (climate: seasonal variation in temperature, humidity, etc.)
- biotic factors (resource distribution: habitat, producers, prey, etc, AND species interactions: competition, predation, etc.)
What is success defined as?
survival and reproductive success
How successful will a species be in a given environment?
- abiotic factors (climate: seasonal variation in temperature, humidity, etc.)
- biotic factors (resource distribution: habitat, producers, prey, etc. AND species interactions: competition, predation, etc.)
note: dispersal is not included here - in most cases, the probability that a species will disperse to a particular location is independent of the probability that it will be successful at that location
How does an interaction affect fitness?
fitness with vs. without the interaction
only way we can determine how an interaction affects an individual’s fitness is to measure:
- the individual’s fitness when the interaction occurs
- the individual’s fitness when the interaction doesn’t occur
and then compare the two!
