Lecture 2 - Ecology Flashcards
Define ecology
Relationship between organisms with each other and environment
What is the difference between a population and a community?
- Population = all individuals species living and reproducing at same time and place
- Community = local populations of multiple species that may interact
Describe the spatial and temporal distribution of humpback whales
- Spatial = feeding areas in north/south where krill are and breeding areas in warmer conditions
- Temporal = migration between feeding and breeding areas
Define ecological niche, how it can be graphed and what they are the result of
- The ways an organism uses the resources of its environment
- Environmental dimension x environmental dimension and where species fall based on dimension requirements
- Result of physiological tolerances and competition
Describe how WA corals are part of an ecological niche based on temperature
Intertidal vs subtidal + heat stress = intertidal had greater variation of heat stress
Describe how rocky shore zonation is an example of an ecological niche and what happens when a species is removed
- Structured higher shore vs lower shore bc wave action changes heat/air exposure
- Remove 1 = invasion by competitors
What is the competitive exclusion principle? Give an example
2 species with identical requirements can’t coexist but compete eg 2 types of barnacles competing for space
What are the 2 types of niches?
- Fundamental = habitat based on physiological needs
- Realised = actual conditions including all factors eg competition
How did Robert Payne study competition and predation in intertidal communities?
- Mussels as dominant competitor and starfish as general predator
- Threw starfish out of area
- Result = reduced community diversity, mussels outcompeted others
What is a keystone species?
Has a disproportionately large impact on community
Describe trophic cascades based on the food web of orcas, otters, urchins and kelp
- Top down effects = more of 1 level means less of levels below it
- Diagram arrow size = importance of interaction
- Predation from availability and behaviour eg foraging preferences (temporal)
How do predators have direct and indirect interactions with prey?
Eats prey A directly which indirectly affects competition between prey A and prey B
How do predators cause non-lethal effects?
Apex predators indirectly change behaviour and prey of predators and prey below them
What are the 2 types of control in a trophic cascade?
- Top down control
- Bottom up control
Define ecosystem function and why it’s used
- How everything fits together, productivity, processes etc
- Determine what to conserve
Which is a better determinant of ecosystem processes - species diversity or functional diversity? Explain why
- Functional diversity = what traits are needed for different processes
- Functional traits predictt ecosystem processes better than species diversity
