Natural and Human Impacts - Coggle Diagram
Natural and Human Impacts
Change Due to Natural Events
Bushfires is a common event in Australia and they burn through natural vegetation, plantations and towns.
Humans - lit on purpose or accident
After a fire, much of the bush regenerates through germination
Eucalyptus are adapted to survive fires. Thick bark insulates the living cells beneath it against the heat of the fire and so it keeps the growing part of the trunk and branches alive, After a fire, new growth sprouts from the trunk and branches. All the leaves may have died, so new ones must grow to allow the plant to begin photosynthesis.
Epicormic growth is the growth of new shoots from the stems of trees and shrubs after a fire. The new growth of shoots allows the plants to quickly produce food and gain an advantage over other plant species that were killed and rely on seeds to regenerate.
A mallee is a type of eucalypt that has lignotubers. Lignotubers is a swollen underground stem of eucalypts that can resist fire.
Drought is a period of no rain or low rainfall.
Drought can change ecosystems by increasing the death rate of plants and animals.
Loss of plant cover also leads to soil erosion by wind. When the rain returns, water erosion can further damage the land by washing away the soil.
Natural events that affect our ecosystems.
Heavy rains can result in floods where rivers overflow their banks to cover normally dry areas of land.
The flooding also greatly affected natural ecosystems and there were high death rates among native plants and animals. Animals drowned because lack of oxygen and plants drowned because lack of oxygen at their roots.
In drier areas, the increased rainfall leads to an explosion of life.
Animals and plants in dry areas adapt to reproduce rapidly to take advantage of the extra food and favorable living conditions.
Change Due to Human Impact
Introduced species are plants and animals brought to Australia from another country.
Feral animals are introduced animals that live in the wild.
Over cropping of animal population means killing animals that can be replaced by the normal breeding cycle.
Habitat destruction is damage done to the environmental factors an organism depends on for survival.
Chemical pollution is chemicals escaping into the environment that can damage ecosystems.
Plastics are becoming a significant problem in oceans and lakes.
Cosmetics - tiny microbeads of plastic to help clear the skin.
Synthetic clothes - nylon break down in washing machines and become tiny fragments called microfibers.
Microfibers and microbeads are able to enter bodies of lower order consumers - mussels, clams and shrimps. These plastic fragments absorb heavy metals (lead, chemicals - polychlorinated biphenyls (PCH)), which is poisonous to organisms.
Global warming is carbon dioxide polluting the Earth's atmosphere causing it to get hotter.
Humans affect the ecosystems in a negative way.
Clearing land destroying places where species live.
Disposing of toxic wastes into natural ecosystems.
Insecticides are chemicals that kills insects.
DDT entered the food chain because it was carried by wind and water onto the land and into lakes and oceans. The chemical was absorbed by plants and animals that lived in the water.
Cumulative poisons that build up over time in organisms.
Biological control uses natural enemies against the pest species. Biological control is being used where possible because it doesn't damage ecosystem's as much as chemicals.