Topic 10 Ecosystems (incl 10.4) Flashcards
What is a biosphere?
Volume of the earth’s surface where organisms can be found
What is ecology?
Study of interactions between organisms and their environment
What is an ecosystem?
A community of living organisms interacting with each other and with abiotic components
What are examples of abiotic components?
Light intensity, water, temperature, minerals, altitudes
What is a community?
Populations of all the different species of organisms living in a habitat at any time
What is the definition of a species?
A group of organisms that can interbreed and produce fertile offspring
What are autotrophs?
Producers
Make their own food
Plant and algae photosynthesise to produce ATP to make glucose from CO2 and H2O
What are heterotrophs?
Primary or secondary or tertiary consumers
Organisms that eat plant material exclusively
Herbivores or carnivores
What are decomposers?
Final tropic level
Break down animal and plant remains returning nutrients to soil
Why are energy loss along a food chain?
Significant amount of energy dissipated as heat from cellular respiration
Some die without being eaten
Not all dead animal/plant can be digested by consumers
What are issues with pyramids of biomass?
- dry mass has to be taken or estimated
- diff components of biomass have different energy contents per kilogram
- doesn’t take into account reproduction rates and the effect of time/season on relative biomass
What is an advantage of pyramid of biomass?
Amount of energy in trophies level more accurately represented
How to measure pyramids of energy and what’s its unit?
Calorimeter
Kj m-2 yr-1
What are limitations of all pyramids?
-only provide a snapshot view of the ecosystem
- population size fluctuate overtime
- many assumptions built in
How to assess abundance?
- individual counts
- percentage cover
- ACFOR scales (abundance, common, frequent, occasional, rare) (very subjective)
Why are species disappearing?
- deforestation
- hunting (humans or predators)
- competition for resources (between species)
- pollution: soil, rivers, lakes
How can the aims of conservation be achieved?
- education
- captive breeding programs to reintroduce species
- relocate/culling foreign species
- set up nature reserves
What is CITES?
- International agreement to regulate trade and products made with living organisms
- 3 appendices
- ensure that international trade in specimens of wild animals and plants does not threaten the survival of the species
What does CITES stand for?
the Convention on International Trade in Endangered Species of Wild Fauna and Flora
What are some CITES successes and failures?
- extended lifeline to many species as given new international protections
- many requests ignored
- level of (il)legal trades increased
What causes human population explosion?
- humans learnt to farm
- reliable sources of food
- more children survive and reproduce
- improving healthcare
What are consequences to human population explosion?
Link to climate change, from need to provide food, shelter and goods
- deforestation to grow crops
- depleting fish from oceans
- development of engines releasing exhaust gases
What are consequences to human population explosion?
Link to climate change, from need to provide food, shelter and goods
- deforestation to grow crops
- depleting fish from oceans
- development of engines releasing exhaust gases
What are three major effects of human influences on ecosystem?
- climate change
- loss of biodiversity
- depletion of biological resources
Strong correlation does not mean…
Causation!!
What are trophic levels and examples?
Organisms’ feeding relationships with other organisms
- producer, primary consumer, secondary consumer
Why is some energy lost at each trophic level?
Used and released for respiration (heat and movement)
Some parts not consumed
Some lost from excretion
What are some biotic factors?
Predators, disease, competition, availability of mates
Why is using a diversity index a better measure of biodiversity than counting the number of species? (2 marks)
- index counts for population
- since numbers of organism in each species vary
What are limitations of CITES?
- not all countries have signed it
- monitoring is expensive
- some animals move across country boundaries
What is population?
Number of organisms of a particular species in an area
