M P bio 2 succession Flashcards
what is succession?
the process by which a community changes over time, due to environmental change, due to species present
what is a pioneer species?
the organisms that first colonise an area (e.g. marram grass in sand dune ecoosystem)
what is a climax community?
the final stage of ecological succession. it is stable and changed very little. same species present for long periods of time and abiotic factors are constant and population sizes stable
what is a climatic climax?
the species that make up the climax community depend on the climate of the ecosystem so is the climax community for a particular climate
what is hostility?
abiotic factors are unfavourable, few species adapted to survive in these conditions
what is diversity?
the relationship between the no. of individual organisms and the no. of species within a community. diverse community= wider range of species and greater no. of individuals of each species present
give a brief overview of the process of succession
-pioneers
-alter environment (make conditions less harsh
-allow more diff species to become established
-more habitats and increased biodiversity
-climax community
give a detailed overview of the process of the 1st stage of succession (pioneer species)
pioneer species establish in an area and change abiotic factors. they die and are decomposed by microorganisms into dead material (humus). make abiotic factors less hostile. humus retains water + nutrients allowing for better adapted plants to outcompete them
describe the 2nd stage of succession after the pioneer species are beginning to be outcompeted
nitrogen fixing bacteria form ammonia from the N2 in the air, then they form ammonium ions which then form nitrates
describe the 3rd stage of succession
some new species make the environment less suitable for previous species e.g. water availability and nutrient availability
describe the final stage of succession
the dominant species are the ones that cause most change to the abiotic environment.
stable community (succession has ended)
same species present
abiotic factors constant
population size constant
what different factors increase as succession occurs?
-stability
-abiotic factors hostility less harsh
-niches
-biodiversity
-complexity of food webs
what is secondary succession?
occurs after a forest fire or clearance of agricultural land as spores, seeds and vegetative organs may remain viable in soil + influx of animals and plants through dispersal + migration from the surrounding area. so doesnt begin with pioneer species so time taken to reach climax community decreased
what is it called when succession is stopped (often associated with human activity) and doesnt reach the climax community?
deflected succession
what are the 4 ways deflected succession can occur?
grazing, fertilisers, use of herbicides, mowing/burning
what is grazing?
sheep eat grasses meaning that the community cannot advance past this stage. climax community is not reached
how can fertilisers be used for limiting succession?
farmers add fertilisers that increase the soil fertility and it may be that some species utilise the nutrients faster than others and outcompete some species
how are herbicides used for limiting succession?
reduces biodiversity and can stop a climax community being reached
how is mowing/ burning used for limiting succession?
areas of moorland are maintained to preserve habitats for moorland birds and other wildlife
what factors limit the populations in a climax community?
-availability of nutrients
-light intensity affecting the rate of photosynthesis
-niches available
-competition for resources
-diseases killing weaker members of species
what is conservation?
the protection and management of species and habitats in a sustainable way
what does conservation being a dynamic process mean?
conservation methods have to be adapted to the constant changes (caused naturally and by humans) that occur within the environment
what are the issues with conservation and how can they be solved?
often conflict between human needs and conservation and careful management is needed to find a balance between the two and maintain sustainability of natural resources
what is an example of a conservation method?
management of succession
what are the reasons for conserving natural habitats?
-conserves habitats/ niches
-species (maintains biodiversity) conserves endangered
-reduces global warming
-sources of medicines
-encourages tourism
-improves aesthetics of the area
