B7: Ecology Flashcards
State the levels of organisation in an ecosystem
- individual, population,community, ecosystem
what is an ecosystem?
- the interaction between the biotic components and abiotic components
State the 4 factors that plants may compete for:
- light
- space
- wate4
- mineral ions from soil
State 3 the factors that animals might compete for
- food
- mates
- territory
what is intraspecific competition?
- competition within a species
what is interspecific competition
- competition between different species
what is interdependence?
- different species in an ecosystem depend on each other for various resources ,
what is a stable community?
- A community in which all the biotic factors and all abiotic factors are balanced
- so that population sizes remain relatively constant
Define a ‘ community’
All of the populations of different species living together in a habitat
Define abiotic factors and give three examples
abiotic: the non-living aspects of an ecosystem
examples: temperature, light and wind intensity, soil pH, oxygen levels
Define biotic factors and give three examples
biotic: The living components of an ecosystem
examples: food availability, pathogens,
predators
why might light intensity affect plants in an ecosystem?
different species of plants may have different optimum light intensities for growth
why does temperature affect an ecosystem?
different species of plants and animals may have different optimum temperatures for growth and survival
how does soil pH affect an ecosystem?
- certain plants may grow better in either alkaline or acidic soil
- soil pH may affect the appearance of the plant
How does moisture level affect an ecosystem?
- many plants cannot survive in waterlogged soil as their roots cannot respire
- certain plants are adapted to high moisture levels
How does low wind intensity affect an ecosystem?
- plant seeds are more likely to germinate in locations with lower wind intensity
- which may also attract animals that depend on the plant to live nearby
How does soil mineral content affect an ecosystem?
- most plants require a high level of soil minerals to grow well
Give an example of a type of plants that have adapted to low soil mineral content
- carnivorous plants catch insects to compensate for the low level of soil mineral content
How does carbon dioxide concentration affect plants in an ecosystem?
- higher Co2 concentration leads to more plant growth
How does oxygen concentration affect an ecosystem? aquatic animals
- aquatic animals cannot survive in areas with low O2 concentration
Define ‘ adaptations’
- features that enable organisms to survive in their living environment
what are organisms living in extreme environments called?
- extremophiles
give three examples of extreme living environments
- high temperature
- high pressure
- high salt concentration
State an example of where extremophile bacteria can be found
in deep sea vents
Define population
a species that interbreed and occupy the same habitat
Define habitat
- the place in which an organism lives
What do food chains show?
- the feeding relationships of different organisms and the flow of energy between the organisms
Define biomass
- the total mass of living material
what are trophic levels
the stages in a food chain
what do arrows in a food chain represent?
- the direction of biomass transfer
- the flow of energy
describe a simple food chain
producer - primary consumer - secondary consumer - tertiary consumer
what is a producer and what types of organisms are primary producers?
- an organism that makes its own food
- photosynthetic organisms like green plants and algae that trap energy from the sun
what are primary, secondary, tertiary consumers?
primary: an organism that feeds on producers
secondary: an organism that feeds on primary consumers
tertiary: an organism that feeds on secondary consumers
what is a predator?
- a consumer that kills and eats other animals
what is prey?
- an animal that is killed and eaten by another animal
Describe the pattern of predators and prey in a stable community
- the numbers of predators and prey rise and fall in cycles
why are producers the first trophic level?
- producers provide all biomass for he food chain ( production of glucose via photosynthesis)
- the rest of the food chain involves the transfer of this biomass
what piece of apparatus is used to measure the abundance and distribution of organisms in an area?
- quadrat
what piece of apparatus is used to study the distribution of organisms across a gradient?
- belt transect
when considering the abundance of organisms, what is meant by the term ‘ mean ‘
- the average number of organisms
how is the arithmetic mean calculated?
- sum of each number of each organism / the total number of each type of organism
when considering the abundance of different organisms, what is meant by the term ‘’ mode ‘’
the most populous organism
when considering the abundance of organisms what is meant by the term ‘‘median’’
- organism that represents the middle value when the numbers of each organism are arranged from lowest to highest
Required practical: measuring the population size of a common species in a habitat
- choose a starting point on the school field in an area where the grass is often cut
- use random numbers to generate a set of coordinates to place your first quadrat
- count the number of different plant species within this quadrat (the species richness)
- return to your starting position and repeat steps two and three a further 14 times using different random numbers
- repeat steps one to four for a part of the school field which the grass is infrequently cut
- compare your results by calculating a mean for each location
Describe how materials cycle through the living and non-living components of an ecoystem
- organisms take in elements from their surroundings eg soil air
- these elements are converted to complex molecules which become biomass
- they are then transferred along food chains
- elements are then returned to environment during excretion and decomposition of dead organisms
Give three molecules which are cycled through ecosystems
- oxygen
- carbon dioxide
- water
Describe the carbon cycle
- plants fix carbon dioxide into organic molecules during photosynthesis
- the organic carbon-containing molecules are passed onto organisms that eat the plants
- carbon dioxide is released back into the atmosphere by respiration from animals and plants
- burning fossil fuels also releases carbon dioxide into the atmosphere
why is the carbon cycle important?
- carbon-containing molecules such as glucose are important for living organisms
- to grow and provide energy for vital functions within cells
Describe the water cycle
- water from lakes and oceans evaporates
- the evaporated water condenses into clouds and returns to earth as precipitation
- the water from precipitation is useful for life on land
- the water then returns to rivers and oceans through surface runoff