TBR 2 - Ecology Flashcards
List the 4 key elements of the environment
- Temperature = narrow range
- Water = required by all
- Sunlight = energy
- Soil = pH, consistence, composition for plants
How do organisms cope with short term environmental variation?
Homeostasis = behavioural, physiological, morphological mechanisms to maintain steady state internally
Define norm of reaction
Ability to produce multiple phenotypes from single genotype based on environmental conditions
What is Allen’s rule?
Mammals from colder climates have shorter ears and limbs to minimise SA to reduce heat loss
List the 3 important characteristics of population ecology
- Population range = area in which population occurs, can expand/contract and can be dispersed/transferred
- Pattern of spacing of individuals within range depending on their interactions
- How population changes size over time
Define metapopulation and its importance
- Species existing as network of distinct populations that exchange individuals
- Prevents long term extinction and allows larger population range
Define source-sink metapopulations
Meta-population established where some habitats suitable for long-term population maintenance and others not = dispersers to maintain poorer habitats
What 2 ways can a community be defined by?
- Species richness = number of species
- Primary productivity = amount of energy produced
How do communities change over space and time?
Species respond independently = community composition changes gradually in terms of species abundance
Define ecotones and how they affect how a community changes
- Places where environment changes abruptly
- Community changes together
Define niche
Total of all ways organism uses the resources of its environment
Define interspecific competition
2 species use the same resource and there’s not enough to satisfy both
Define interference competition
Physical interactions over access to resources
Define exploitative competition
Consuming the same resources
What are the 2 types of niches?
- Fundamental = niche capable of using based on tolerance and needs
- Realised = actual environmental conditions incl other species’ presence/absence
Define competitive exclusion
2 species competing for limited resource, the speices that uses it more efficiently will eliminate the other
Define resource partitioning
Multiple species coexisting/avoiding direct competition by subdividing the niche
What is the best way of studying/identifying competition? What are the limitations?
- Experimental studies eg field experiments
- Negative effects don’t always = competition
- Not always achievable eg species exists in wide area
What are the 3 major types of symbiotic relationships?
- Mutualism = both benefit
- Parasitism = 1 benefit 1 harmed
- Commensalism = 1 benefits 1 neutral
How do predators impact competition/exclusion?
Feed on multiple prey sources and pick the most abundant = prevent exclusion by keeping populations more equal
