Chapter 8 - Ecosystems Flashcards
Abiotic
Non living physical and chemical components that effect the environment eg: rainfall, temperature, sunlight
Biotic
Living. All living organisms, their numbers, distribution and interactions
Predation
Occurs when one organism (predator) kills and eats another organism (prey). Eg: fox eats chicken
Allelopathy
Occurrs when a plant/tree releases a chemical to inhibit the growth of other plants. Eg: pine needles release a chemical that inhibits growth
Parasitism
Occurs when one organism (parasite) lives on or in another organism (host) and causes harm. Eg: tick living on dog
Commensalism
Occurs when one organism lives on or in another organism and one benefits and the other has no effect on it. Eg: tree frog - uses tree as protection from rain
Mutualism
When one organism interacts with another and both benefit. Eg: oxpecker bird and rhino, bee and flower
Communal Living
When it is a benefit to live in communities. They can deceive predators, warn off danger and have safety in numbers. Eg: school of fish, herd of zebras
Decomposers
Detritivores (worms, fungi, bacteria etc) feed on dead organic matter (detritus). They break it down into smaller organic molecules that can be recycled into soil.
Competition
When two plants/ animals rely on the same resource. Eg: mouse and grasshopper both eat grass.
Symbiosis
When two organisms live together
Ecosystem
The result of the interactions between the abiotic and biotic factors in an environment
Biotic Factors examples- Plants/Producers (7)
Grass, shrubs, seaweed, hay, moss, ferns, bamboo
Biotic Factors examples- Consumers (7)
Rabbits, dingoes, crabs, wolves, pandas, mouse, elephant
Biotic Factors examples- Decomposers (7)
Worms, dung beetles, lobsters, termites, bacteria, cockroaches, fungus
Abiotic Factors examples (13)
Salinity, pH, nutrients, pollution, humidity, temperature, rainfall, sunlight, water depth, altitude, soil, wind, turbidity
Nitrogen
Needed by all living organisms. Required to make amino
Acids and proteins. Needed for growth and repair of organisms
Atmospheric Nitrogen (N2)
Makes up 70-80% of atmosphere. Cannot be used in this form
Nitrates
NO3 used by plants
Ammonium
NH4 used by some plants. Eg legumes
Other organic nitrogen
Amino acids
Urea
CO(NH2)2
Cycling Nitrogen
Nitrogen goes through the nitrogen cycle and is converted into different forms so it can be used by living organisms
Nitrogen N2 —> Ammonium NH4
Atmospheric nitrogen converted to ammonium by nitrogen fixing bacteria in the soil. Can be found free in the soil or in the root nodules of legumes. This form of nitrogen can be used by only some plants. Eg: legumes
Ammonium NH4 —> Nitrate NO3
Ammonium is converted to nitrates by another bacteria in the soil called nitrifying bacteria. Nitrates can be used by plants
Nitrates NO3 —> Other Nitrogenous Compounds
Nitrates are absorbed by plants and converted into amino acids and proteins. Nitrogen is then cycled through the food chain by animals eating the plants and then more animals eating animals etc
Other Nitrogenous Compounds —> Nitrates NO3
When plants and animals die, detritivores break down the organic nitrogenous compounds releasing ammonium back into the soil and the nitrogen cycle continues. This also happens with waste products such as faeces and urea
Nitrates NO3 —> Atmospheric Nitrogen
Another type of bacteria in the soil called de-nitrifying bacteria, feeds on nitrates and converts it back into atmospheric nitrogen
Humans getting nitrogen
We get nitrogen from the food we eat. Especially legumes and plants which have nitrogen from the nitrogen cycle
Effects of competition for resources on populations
Organisms that try to obtain the same resource are competitors. Sometimes the resource is limited so often the weak, old and young will die in these situations as there is not enough food for all species and individuals.
