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33 Cards in this Set
- Front
- Back
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What two categories of factors affect population size? |
Biotic factors Abiotic factors |
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What's is population size? |
Total number of organisms of one species in a habitat |
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What abiotic factors can cause change in population size? |
PLANTS: Rainfall, sunlight, mineral ions, space
ANIMALS: temperature |
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What happens to the growth of an organisms when abiotic factors are ideal? |
Growth is fast and reproduction is likely more successfull since the organism doesn't have to use energy to overcome the environmental factors |
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What happens to growth of a plants when abiotic conditions aren't ideal? |
Can't grow as fast or reproduce as successfully since energy is being used up to overcome environmental factors |
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What are the 3 biotic factors which can change population size? |
Interspecific competition Intraspecific competition Predation |
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Interspecies competition |
There are limited resources
The better adapted species are more likely to find food and habitats
This leaves fewer resources for the other species who need the same things.
So they die and their population decreases. |
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Intraspecific competition |
Organisms within the species compete for the same resources
Population increases when resources are plentiful. This leads to more organisms and so more competition
Resources become limiting, pop begins to decline
Smaller pop so less competition; more resources so greater growth and reproduction. Pop increases |
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What is the carrying capacity? |
The maximum stable population size of a species that an ecosystem can support |
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Predator and prey populations are controlled by what process? |
Negative feedback |
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Describe the negative feedback between prey and predator |
Prey pop increases, predator pop increases since they have more food As predator pop increases prey pop decreases since more predators As prey pop decreases predator pop decreases since less food available |
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What other limiting factors can there be for populations? |
Diseases Starvation Climate change Deforestation |
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What determines the carrying capacity of an ecosystem? |
Limiting factors |
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What is conservation? |
Maintaining an ecosystem and sustainable management of an ecosystem so that we are still able to use it's resources |
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What does conservation ensure?1 |
Species don't go extinct Habitats are protected |
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How can we conserve? |
Preserving organisms/ environments And fish from human activity Create new habitats |
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Conservation can also be involved in reclamation of an ecosystem. What does that mean? |
Restoring damaged or destroyed ecosystems (after forests get cut) |
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What are the economic reasons why conservation is important? |
Ecosystems provide resources (drugs, clothes, food). These resources are traded. If ecosystems are destroyed, much trade (locally and globally) also will |
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What are the social reasons for conservation being important? |
They're aesthetically pleasing so bring people joy Can be used for activities (walking, birdwatching) |
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What are the ethical reasons for conservation being important? |
Organisms have a right to live, shouldn't suffer bc of humans Morally responsible for preserving them for future generations |
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What is preservation? |
Preservation leaves ecosystems undisturbed |
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How can woodland be managed in a sustainable way? |
•Coppicing; letting trees re-grow •Clear trees in strips or patches; grow back faster between existing woodland than open areas •Cut down small in small areas to avoid soul erosion •Replant native species; adapted and help native organisms thrive •New plants surrounded by plastic tubes to stop grazing •Plant trees spaced out a little; so they don't have to compete for resources |
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How can fishing be managed sustainably? |
•Fishing quotas •International agreements to limit fishing and locations •Controlling mesh size of nets to allow young fish to escape |
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What is the problem with fishing that doesn't have to do with overfishing? |
Captures lots of other marine life and although they throw it back, it most likely dead or dying |
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Describe coppicing |
Cut down to its stump Regrows Can harvest again |
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What is the disadvantages of biological pest control? |
Slow to work Pest don't totally go away May eat crop |
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What are the advantages of not using pesticides?/ disadvantages of using of using pesticides (Organic farming) |
•Higher produce price •No chemical residue on food •Less pollution •Species diversity isn't reduced •Insecticides are slow to biodegrade •Can run off into the water •May kill natural predators or pest |
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What is sustainability? |
Resources are harvested at a level where sufficient organisms can grow and return back to their original level
It can be carried on indefinitely |
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How to control pest? |
Crop rotation; pests won't be there when you grow the plant you need Intercropping Predatory mites Insecticides |
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Describe simple abundance and distribution sampling |
•Mark out appropriate grid •Mark out line transect across area to investigate distribution •Appropriate size quadrant •Interupted line transect every 5 m •Work out % cover •Use key to identify right species •Repeat transect in different areas •kite diagram for distribution •Spearmans index of biodiversity for abundance |
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Why might the numbers of prey in a crop field lessen over a year? |
•As crop is harvested, the mites starve since there is no food •As day light hours lessen, less sunlight reaches plants and so crop growth is slower. Less food is available |
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Large bare ground can cause what? |
Soil erosion, newly planted trees won't grow there then |
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What effect can humans have on an area? |
•Ecosystem destruction •Urbanisation, land used for building •deforestation •Land used for farming •More pollution •Competition from introduced species •Predation by introduced species •New diseases/ pathogens |
