Topic 7C - Populations And Ecosystems Flashcards
What is an ecosystem?
All the organisms living in a community aswell as all the abiotic conditions in the area which they live
What are biotic conditions of an ecosystem?
Living features of an ecosystem. E.g. the presence of predators or food
What are abiotic conditions of an ecosystem?
The non living features. E.g. the temperature or soil
What is a habitat?
The place where an organism lives
What is a niche?
The role of a species in a habitat
What is an adaptation?
Feature that members of a society have that increases their chances of survival
What’s is a population ?
All the organisms of one species in a habitat
What is a community?
Population of different species in a habitat
What is the carrying capacity?
The maximum stable population size of a species that an ecosystem can support
What are 3 biotic factors ?
Interspecific competition
Intraspecific competition
Predation
What is abundance?
Number of individuals of one species in a particular area
What is distribution?
Where a particular species is within the area you are investigating
Give a brief method for random sampling? (5)
- Choose an area to sample
- Ensure sample is random to avoid bias - use random number generator
- Use appropriate technique to take a sample of the population
- Repeat and take as many samples as possible
- Conclude results and work out the mean aswell as percentage cover
What is a running mean? What is the purpose of a running mean?
- Where you work out the mean of all the data each time you collect a new sample
- once the mean no longer changes your should have data that gives a REALISTIC ESTIMATE FOR THE WHOLE AREA
What are transects?
Lines to help find out how organisms are distributed across an area
What are the 2 types of transects?
Belt transects
Interrupted belt transects
What are belt transects?
Quadrats are placed next to each other along the transect to work out species frequency and percentage cover along the transect
What is interrupted belt transects?
Placing quadrat at regular intervals instead of measuring the whole transect
What is ‘mark-release-recapture’ method? (6)
- Capture a sample of species using an appropriate technique
- Mark them in harmless way
- Release them back into their habitat
- Wait a week, then take a second sample from same population
- Count how many of the second sample are marked
- To estimate total population size = number of 1st sample size x number of 2nd sample / number of 2nd sample marked
What is succession?
The process by which an ecosystem changes over time. Happens in a series of stages
What is a pioneer species?
The first species to colonise the area
How do pioneer species change abiotic conditions?
Die and microorganisms decompose the dead organic material, which forms a basic soil
This makes condition less hostile, so new organisms can grow there
Continues to happen and environment gets less and less hostile allowing a wider range of species being able to grow in it
What occurs during the later stages of succession?
Ecosystem becomes more complex, eventually leading to a climax community
What is secondary succession?
Happens on land that’s been cleared of all plants but where the soil remains
Similar to primary succession but the new pioneer species are usually larger plants
What is plagioclimax?
When succession is stopped articifically (due to humans)
What is conservation?
Protection and management of species and habitats in a sustainable way
What are the 5 conservation methods?
Management of succession
Seed banks
Captive breeding
Fishing quotas
Protected areas
