7C Populations in ecosystems Flashcards
What is an ecosystem?
This is where all the organisms living in a community plus all the abiotic conditions as well
What are biotic conditions
Living features of an ecosystem eg predators
What are abiotic condition?
Non living features eg temp or soil
What is the place an organism lives?
Habitat
What is a niche?
This is the role of a species within a habitat eg what it eats, when and where it feeds
What does the niche a specie occupy include
- Its biotic interactions : eg the organism it eats and those its eaten by
- Its abiotic interactions : eg the temp range an organism can live, the time of day it is active
What will happen if 2 species try to occupy the same niche?
They will compete until one specie is left as one is more successful than the other
What is an adaptation?
A feature that members of a species have that increases their chance of survival and reproduction
What are the types of adaptations?
Physiological - processes inside their body
Anatomical - structural features
Behavioral - the way an organism acts
What is a population?
A population is all the organisms of one species in a habitat
What is a community?
populations of different species in a habitat make up a community
What is population size
Total number of organisms of one species in a habitat
What is the carrying capacity ?
Total number of organisms of one species in a habitat
What is interspecific competiton?
Organisms of different species compete with eachother for the same resources.
If two species are competing but one is better adapted to the surroundings than the less well adapted species is likely to be outcompeted
What is intraspecific competition?
Organisms for the same species compete with eachother for the same resources
If the population grows beyond the carrying capacity there wont be enough resources for all organisms and the population will decline, so there is less competition for space and food which is better for growth and reproduction so the pop can grow again
What is predation?
Organisms kill and eats another organism
Population sizes of predator and prey are interlinked so as the pop of one changes the pop of another will change
What is abundance
This is the number of individuals of one species in a particular area
How do you measure abundance
- Frequency : the number of samples a species is recorded in
- Percentage cover : how much of the area you’re investigating is covered by a species
How does random sampling work ?
- Choose an area to sample
- Should be random to avoid bias therefore use a random number generator
- Use an appropriate technique eg quadrats and transects
- Repeat so less results are due to chance
- Take mean of all samples
What is a running mean
Work out the mean of all the data each time you collect a new sample
What are the methods for investigating populations
Quadrats
Transects
How does quadrats work
It is a square frame divided into a grid of 100 smaller squares
- Placed on the ground at different points
- Measure species frequency or number of individuals of each species
How does transects work and the different types
- Belt Transects : quadrats placed next to eachother along transect to work out species frequency and percentage cover along transect
- Interrupted Belt Transects : Instead of investigating the whole transect you can take measurements using a quadrat placed at regular intervals
How do you capture motile organisms
- Net
- Pitfall trap
What is Mark Release capture?
- Capture a sample of species using an appropriate technique
- Mark in a harmless way
- Release back into habitat
- Wait a week, and take a 2nd sample from same population
- Count how many of second sample are marked
How do you calculate Mark Release capture?
number caught in 1st sample x number caught in 2nd sample /
number marked in 2nd sample
How do you ensure Mark Release capture method is accurate ?
- The marked sample has enough time and opportunity to mix back in with the population
- The marking hasnt affected the individuals chances of survival and is still visible
-There are no changes in population size due to birth, migration and deaths
What is succession
The process by which an ecosystem changes over time
What is primary succession
- Species colonise a new land surface
- Seeds and Spores are blown in by the wind and begin to grow
- First species to colonise area are called PIONEER SPECIES
- Only pioneer species cope as they have adapted to cope with harsh conditions
- The new organisms then die and are decomposed adding more organic material so the soil is richer in materials
- Nitrogen fixing bacteria turn nitrogen from the atmosphere into ammonia forming ammonium ions so it can be used
- Dominant species will out compete the plants and animals already there
- Ecosystem becomes more complex as more species move in, plants create more habitats, abiotic conditions less hostile and biomass increases
9.Climax community
What are some examples of hostile abiotic conditions
- Limited water available as theres no soil to retain water
- Few minerals or nutrients as theres no soil
- High Light intensity and fluctuating temperatures
What is secondary succession
This happens on land that has been cleared of all the plants buy where the soil remains
What is plagioclimax
This is where succession was stopped artificially
What is a climatic climax community
Where the climax community is dependent on the climate in an ecosystem
What is conservation
The protection and management of species and habitats in a sustainable way but as a dynamic process
How is seed banks a conservation method?
They act as backup for the conservation of plant species
How is captive breeding a conservation method?
- Breed Animals in controlled environments so they can then be reintroduced into the wild
How is fishing quotas a conservation method?
Limit to the amount of fish species that fishermen are allowed to catch so less are killed
How is protected areas a conservation method?
They restrict urban development, industrial development and farming
