succession Flashcards
what is succession
series of changes within a coomunity eith time from its origin bare soil to its climax community
what is a pioneer species
the organisms that first colonise an area e.g. marram grass in sand dune ecosystem
what is climax community
the final stage in an ecological succession. A climax community is stable and changes little.
includes a stable community, abiotic factors more or less constant, population size stable around carrying capacity.
what is hostility
abiotci factors are unfavourable, few species adapted to survive in these conditions
in hostile environments diversity is low and abiotic factors dominate the distribution of species
in less hostile environments diversity is high and biotic factors dominate
what is diversity
the relationship between the number of individual organisms and the number of species within a community
can be measured by diversity index
what is high diversity associated with
a stable eco system and complex food web. If the population of one species in the ecosystem drops then others will be able to increase in numbers and fill the niche so that the community is not affected much by chance
what is low diversity associated with
unstable ecosystem and a less complex food web. If one species dies out then the whole ecosystem may be disrupted.
there are 6 points
what is the process of primary succession
1) pioneer species colonises area
2) when they die they add hummus to the ground as they decompose and add nitrates to the soil
3) this alters the environment and makes the conditions less harsh
4) this allows different species to establish
5) more habitats and increased biodiversity
6) climax community
5 points
what always occurs during succession
- abiotic environment becomes less hostile to allow new species to colonise
- greater number and diversity of habitats
- increased biodiversity
- more complex food webs
- increased biomass
when would you use a logarthmic scale on a graph
when representing the growth of a population of microorganisms, log graphs can be used when there is a large scale of results
what are turbidity measurements
the cloudiness caused by cells suspended in solution used to investigate the growth rate of a broth culture of microorganisms
what is secondary succession
occurs after forest fire or clearance of land. Spores, seeds and vegetative organisms may remain viable in the soil and there will be an influx of animlas and plants through dispersal and migration from the surrounding area. Succession does not begin with a pioneer species but with species from intermediate communities.
what is deflected succession
when the climax community is prevented from establishing, due to management practises by humans etc.
why does managing a succession aid conservation
deflected climaxes would exist and this would cover the countryside
how does conservation maintaining biodiversity
- ethical issues - respect for living organisms, all livign things have a right to survive
- aesthetic issues - appretiation for the country side
- economic issues - plants and animals can provide useful medicines etc
- ecological - ecosystems detoxify waste, pollinate crops and purify water
what are the ethical issues surrounding conservation
- management of a particular habitat involves the destruction of an other
- initial work can be unnattractive
- work can be labour intensive and costly
- financing can come from sports such as shooting e.g. pheasants
