19: Ecosystems Flashcards
Define ecology
The study of inter-relationships between organisms and their environment
Define abiotic and biotic factors
Abiotic = non-living factors Biotic = living factors
Give some examples of abiotic factors
Temperature
Rainfall
Give some examples of biotic factors
Competition
Predation
Define a community
All the populations of different species living and interacting in particular place at the same time
Define an ecosystem
Dynamic systems made up of a community and all the abiotic factors
What are the two processes in an ecosystem which should be considered?
Flow of energy
Cycling of elements
Define population
Group of individuals of one species, in the same habitat at the same time that could interbreed
Define carrying capacity
Size of a population that an ecosystem can support
How does the size of a population vary?
Effect of abiotic factors
Interactions between organisms (biotic)
Define a habitat
Place where an organism lives and is characterised by the physical conditions and other organisms present
Define a microhabitat
Smaller units within habitats called microhabitats with their own microclimate
Define an ecological niche
Where an organism lives and what it does there
What is the competitive exclusion principle?
No two species occupy exactly the same niche
Define population size
Number of individuals in a population
What should be done to the population size if it increases at a ever-increasing rate? e.g bacteria growth is exponential
Plot the log number of bacteria
This shows all data points
How is temperature a limiting factor for plants cold-blooded animals? (e.g reptiles)
Too cold: Reactions slow down (enzymes slow down) and metabolic rate is reduced
Carrying capacity of a population decreases
Too hot: enzymes will denature
Carry capacity decreases
How is temperature a limiting factor for warm-blooded animals?
Any change: although animals maintain body temp
Significant change causes a large amount of energy spent to maintain it
Less energy for growth and maturation, reproductive rate decreases
Carrying capacity of the population is reduced
How is light a limiting factor?
Ultimate source of energy in ecosystems
More light, more photosynthesis, plants grow faster
Carrying capacity increases
Carrying capacity of consumers etc. could increase
How is pH a limiting factor?
Affects action of enzymes (denaturation)
Population of organisms in optimum pH is larger than that where pH is not optimum
How is water a limiting factor?
Populations are small where there is a lack of water unless well adapted
Water is essential
How is humidity a limiting factor?
Effects transpiration rates
Dry air causes a large amount, meaning non-adapted organisms will die quickly
Define intraspecific competition
Competition between members of the same species
Define interspecific competition
Competition between members of different species
Give some examples of things organisms compete for
Water
Food
Breeding sites/partners
How does availability of resources effect population size in intraspecific competition?
Increase in availability causes increase in population
How does availability of resources effect population size in interspecific competition?
One population will normally have an advantage
That population will increase gradually and the other decreases
Can two species occupy the same niche if there are limiting resources?
No, cannot happen as one will have an advantage
What does an increase in food supply cause?
More individuals are likely to survive
Increased probability of reproduction and population will increase
Takes a long time to take effect
Define predator
An organism that feeds on another organism (prey)