Ecology Flashcards
What is a population?
Group of organisms of same species in the same habitat
What is a habitat?
Part of ecosystem in which specific organism lives in
What is a community?
All the populations of different species in same area + same time
What is an ecosystem?
The community + all the non-living parts of the environment
What is a niche?
An organisms role in an ecosystem e.g. position in food web
What is the carrying capacity?
The maximum population size an ecosystem can support
What would occur if 2 species shared a niche?
They will go into competition and 1 will outcompete the other until there is only 1 in that niche
What will occur if the population goes over the carrying capacity?
The population will have an increased death rate because there not enough food to support or not enough space to support
What are abiotic factors
Non- living e.g. light intensity, temperature, soil pH, O2 concentration
What are biotic factors?
Living e.g. number of plants, predators
How do abiotic factors affect population size?
The less harsh the factors e.g. enough light/water/right temperature = more range of species + larger population size
How does temperature affect population?
Each species optimum temperature for survival and if temperature is different= enzymes work less= less metabolic rate/denatured enzymes or energy used to maintain temperature = less growth= carrying capacity reduced
How does light affect population?
Increased intensity = rate of photosynthesis increased= more seeds produced= carrying capacity increased
How does pH affect population?
Each organism’s enzymes have an optimum pH so where pH is appropriate = larger population but different pH= smaller population
How does water and humidity affect population?
Scarce water= only organisms that are adapted
Humidity affects transpiration rate= only plants with adaptations survive in low humidity
How do biotic factors affect population size?
Competition and predation affect population size
Describe interspecific competition
- Different species
- Compete for space or food
- Species better adapted to environment is more likely to succeed
Describe intraspecific competition
- Same species
- Compete for resources and mate
- Individual which is fitter and better courtship ritual + better fur/ feathers = more likely to get mate
Describe the pattern between the predators and prey relationship
-Increase prey= more food for predators= more predators reproduction
-More predators = less prey as they get eaten= not enough food for predators = less predators
- will always be more prey > predators
- lag time from prey - predator population change
Why do we sample?
As it is more time efficient and more accurate than counting individuals over a large area
How can we ensure sample accurately represent the population?
- Random sampling to eliminate bias
- Large sample 30+ to make sure you accurately represent
Describe sampling for slow or non-motile organisms
Using a quadrat
- UNIFORM DISTRIBUTION: Random sampling
UNEVEN DISTRIBUTION: Line transects
Describe sampling of motile organisms
Using mark-release-recapture
Explain the random sampling method
- Line 2 tape measures at a right angle to create a gridded area
- Use random number generator to generate 2 coordinates
- 2 people will walk along coordinates and where they meet place quadrat
- Collect percentage cover/frequency
- Repeat (1-3) 30 times and calculate average
