Ecological succession Flashcards
What is meant by conservation?
Method of maintaining ecosystems and the living organisms(biodiversity) that occupy them. It requires planning and organisation to make the best use of resources while preserving the natural landscape and wildlife. It often involves the management of succession.
What is meant by succession?
The changes that occur in ecosystems over a period of time. The biotic conditions change as the abiotic conditions change
What are some examples of succession?
When a bare rock or other barren land is first colonised by a pioneer species:
- a glacier retreating and depositing rock
- sand being piled into dunes by wind or sea
- volcanoes erupting and depositing lava
What is meant by a pioneer species?
A species that can colonise bare rock or ground, first stage of succession
What features do pioneer species have that suit them to colonisation?
- Tolerate to harsh conditions
- Can fix nitrogen from the atmosphere
- Can photosynthesis and thus produce their own food without depending on other species
- Can produce vast quantities of wind-dispersed seeds/spores
- Rapid germination of seeds on arrival of colonisation
What are the events of ecological succession on land?
- Barren Land
- Primary/pioneer species colonises
- Secondary colonisers
- Tertiary colonisers
- Scrubland
- Climax community
What is primary succession?
The progressive colonisation of bare rock or other barren terrain by living organisms
What is secondary succession?
The recolonisation of an area after an early community has been removed or destroyed
What is the climax community?
The organisms that make up the final stage of ecological succession
What occurs in the climax community?
A dominant plant species and a dominant animal species
What features occur during any succession?
- Non-living environment becomes less hostile
- Greater number and variety of habitats
- Increased biodiversity
- More complex food webs
- Increase biomass
What is meant by biomass?
The total mass of living material in a specific area at a given time. It is usually measured as dry mass because the amount of water in an organism is very variable.
What are the main reasons for conservation and why?
- Ethical: other species have occupied the earth longer than us so we must show respect
- Economic: Using the gene pool of organisms to make millions of substances which may prove valuable in the future
- Cultural: To improve aesthetic qualities
- Prevent climate change: stop the burning down of forests which release c02 into the atmosphere
- Prevent disruption of food chains: Loss of resources and affect the number of a population of certain species
What can stop a climax community from developing?
Human activity e.g. mowing grassy fields prevents shrubs and trees from growing
How can habitats and species be conserved?
- Storing plants in a seed bank: if plants become extinct can plant new ones
- Conservation of fish species using fishing quotas: limit the amount of certain fish species that fisherman are allowed to catch
- Conservation of animals by captive breeding programmes: Breeding animals in controlled environments, helps increase the population of endangered species
- Relocating an organism: moving them to a safer area but to a similar environment to where the organism was originally from
- Conserving habitats using protected areas: national parks and reserves
