Assumed Test 3 Questions Flashcards
Name 3 ways atmospheric nitrogen is fixed.
- Nitrogen fixed by lightning
- Fixed by bacteria in soil
- Fixed by root nodule bacteria of legumes (Rhyzobium)
What is the term used to describe the transition from the nitrogen being fixed to ammonium.
- Ammonification (performed by soil fungi and bacteria)
What is the term used to describe the transition from the ammonium to Nitrites
- Nitrification
What is the term used to describe the transition from the Nitrites to Nitrates
- Nitrifies
How does Nitrogen reach the ocean?
- Brought by rain and run off and the activities of nitrogen fixing organisms. The sinking of nitrates and other nutrients make the ocean a relatively poor environment in terms of available nutrients.
How much of the air is nitrogen?
- 80%
Name 3 Carbon sinks/reservoir
- Consumers
- Sediments
- Coal, oil, gas
- Mantle
- Ocean
What are the 3 types of respiration in the carbon cycle?
- Animal
- Plant
- Root
Does photosynthesis belong in the carbon diagram?
YES
Name 2 causes of climate change
- Burning of fossil fuels - burning them released carbon in to the atmosphere, contributing to the greenhouse affect as heat cannot escape earth.
- Deforestation - carbon released. Carbon cant be stored. Burning amazon is an example.
Name 2 global affects of climate change
- Loss of biodiversity - animals cannot handle change in environment and cannot adapt.
- Rising sea levels - affect coastal towns.
- Coral bleaching - water heating up and destroying coral marine ecosystem
Give an example of a good introduced species in Australia.
- Wasps lay eggs in caterpillars that then mitigate the growth of the caterpillar population
- ladybugs eat aphids and fertilisers
- Dragonflies control mozzie population
Define Biomagnification:
Successively higher concentration of non bio-degradable chemicals (eg. pesticides, plastic) build up in tissues of organisms in high trophic levels of food chain.
Define Bioaccumulation:
Toxins enter food web by building up in individual organisms.
Name and describe 3 ways biomagnification occurs.
- Persistance - substances cannot be broken down.
- Bioaccumulation - concentration increases progressively
- Low/non-existent rate of internal degradation. - mainly due to to water insolubility
What is DDT
DDT is a pesticide.
Outline the steps of dryland salinity
- Human population increases - need more food
- Farming increases to provide food - clearing deep rooted trees
- Vegetation changes from deep rooted trees/shrubs to shallow rooted crops - reduced/no transpiration or evaporation
- Water table rises bringing soluble salts to the surface
What is dryland salinity and what causes it.
- Occurs naturally in the landscape, but nature generally has the ecosystem balanced so the salt does not cause a problem. However, human activity often upsets the equilibrium and salinity problems occur.
- Caused by a combination of land clearing and irrigation practices. It can reduce biodiversity and devastate ecosystems because the abiotic changes it causes leads to damaging biotic changes.
What is secondary succession?
- A process of change in an ecosystem when a previously established community is taken over by a group of new organisms
Steps for secondary succession
- A natural or artificial disturbance occurs
- Pioneer plants colonise the area and invertebrates enter the ecosystem
- Slower growing trees begin to grow and stabilise the community. New herbivores, then carnivores and omnivores arrive as part of the food web
- New community forms and eventually becomes a climax community
Steps for Eutrophication
- Excess nutrients enter a body of water
- Algae grows and blooms in population
- Algae blocks plants from sunlight. Algae then run out of food and die.
- Bacteria bloom in population to break down the dead algae.
- Bacteria use up all the oxygen in the water
- Fish die as there is no oxygen in the water.
