Ecology Flashcards
What is an ecosystem
- A system or area where organisms interact with their physical environment
What is population
- The total number of individuals of one species in a particular habitat at a particular time
What is a habitat
- area where specific organisms live
How to find out population of species in habitat
1- Find area of habitat
2- Generate random coordinates to find out where to place quadrat
3- Measure number of species in one quadrat
4- repeat at least 10x and find an average number
5- Calculate how many quadrats fit into total area
6- Divide this number by the average previously found
methods of finding out effects of biotic/abiotic factors
- Random sampling- Quadrat
- Transects
What is a community
- The populations of all the species present in an ecosystem at a particular time
Ways in which species interact with each other
- Feeding (on each other)
- Competition for resources
- Using abiotic resources
What do pyramids of number show
- Show the number of each organism counted in the ecosystem, stacked on top of each other
What do pyramids of biomass show
- show to total mass (mass of individual x number of individuals) of organisms in each trophic level
- more accurate than pyramids of number
How is energy available at a trophic level expressed
- kilojoules per square metre per year (kJ/ m^2/year)
How much of Sun’s energy transferred to producers
- 1-5%
Why is light energy from sun to producer the least efficient transfer?
- Some light misses plant or plant’s chroloplast
- some light reflected by cuticle
- some light has wrong wavelength to be absorbed by chlorophyll
How much energy is passed down to the next trophic level?
- 10%
Why is only small part of energy passed down trophic levels?
- energy lost by
-movement
-heat loss
-egestion of waste - not all of species consumed e.g bones
