10.1- the nature of ecosystems Flashcards
habitat definition
the area or natural environment in which an organism or population normally lives
ecosystem definition
a biological community of organisms which interact with each other and their physical environment
community definition
all the organisms present in an ecosystem at a given time
population definition
a group of individuals of the same species that occupy the same habitat at the same time
niche definition
a term for the position of a species within an ecosystem
biome definition
a specific environment that’s home to living things suited for that place and climate e.g. desert or tropical rainforest
biodiversity
the number and variety of living organisms in the living world
what are abiotic factors
-non living elements of a habitat or organism
abiotic factors example
-air
-water
-light
-wind
-soil
-pH
-temp
-humidity
-inorganic nutrients
what are biotic factors
-the living elements of a habitat that affect the ability of a group of organisms to survive there
biotic factors examples
-other organisms so..
-competition
-predation
-symbiosis (mutualism and parasitism)
-disease agents
climatic abiotic factors
-factors include humidity, sunlight and factors involving the climate
edaphic abiotic factors
-soil conditions, so edaphic abiotic factors include soil and geography of the land
topographic abiotic factors
-physical features of an area including height, direction of slope and steepness of slope
what is succession
-the process of a community changing over time
-heavily influenced by conditions in the environment
how does succession happen
-community consists of all plants and animals in particular area
-individual populations in a community interact
-the community is constantly changing and dynamic, which passes through a number of stages from origin to climax
-transition from one stage to next is succession
primary succession
-progressive colonisation of bare rock or barren terrain by living organisms
secondary succession
-the recolonization of an area after an earlier community has been removed or destroyed
primary succession in steps
-pioneer species begins breaking down rock
-lichens usually grow on rock
-Lichens secrete acids that begin breaking rock into small particles
-more complex plants grow when soil is deep enough
-eventually succeeds lichens
-organic material can hold water
-larger complex plants
-forests if soil deep enough
-Climax community
Is very stable and can endure for hundreds of years.
overall features that emerge in succession
-The abiotic environment becomes less hostile (e.g. soil forms).
-More complex food webs.
-Increased biomass.
-Increased biodiversity – increase in number of species.
-Greater number and variety of habitats and niches.
succession stages summarised
-grassland, small flowering plants
-tall herbaceous plants
-bushes and shrubs
-fast growing trees
-larger, slower growing strong trees
summary of succession (mark scheme)
1.Pioneer species/mosses/lichens arrive
2.decomposition increases the soil depth and mineral/nutrient content.
3.Therefore larger plants can grow.
4.More herbaceous plants/shrubs/trees are present.
5.Nitrate content in soil grows as there are more leaves/plants/animals/faeces.
6.Climax community emerges at end.
where does secondary succession take place
areas where life is already present but has been altered in some way
-faster than primary
3 main causes of secondary succession
1.natural catastrophe (fire)
2.human destruction
3.human management (ploughing)
