biodiversity and the effect of human interaction on ecosystems

Question 1

biodiversity

definition

Answer 1

The range of animals and plants in a given area.

Question 2

biofuel

definition

Answer 2

A type of energy source derived from renewable plant and animal materials, eg ethanol (often made from corn in the United States and sugarcane in Brazil), biodiesel (vegetable oils and liquid animal fats) and biogas (methane from animal manure).

Question 3

combustion

definition

Answer 3

The process of burning by heat.

Question 4

conservation

definition

Answer 4

Where no energy is lost. If 10J of potential energy is conserved by a falling object, the object’s kinetic energy will be 10J when landing.

Question 5

deforestation

definition

Answer 5

The cutting down of trees and forests to allow a different land use.

Question 6

ecosystem

definition

Answer 6

The living organisms in a particular area, together with the non-living components of the environment.

Question 7

endangered species

definition

Answer 7

Animals that are close to extinction because of their low numbers.

Question 8

eutrophication

definition

Answer 8

‘Hyper-nutrition’ resulting from fertiliser pollution of aquatic ecosystems.

Question 9

exponential

definition

Answer 9

A set of numbers that increase more and more rapidly.

Question 10

greenhouse effect

definition

Answer 10

The retention of heat in the atmosphere caused by the build-up of greenhouse gases.

Question 11

greenhouse gas

definition

Answer 11

The gases responsible for global warming - carbon dioxide, methane, nitrous oxide and CFCs (chlorofluorocarbons).

Question 12

peat bog

definition

Answer 12

Peat bogs are poorly drained areas made up of partially decomposed organic matter due to waterlogging.

Question 13

pollution

definition

Answer 13

Contaminating the air, water or ground with harmful substances.

Question 14

reforestation

definition

Answer 14

The replanting or regeneration of areas of forest which have previously been damaged or destroyed.

Question 15

smog

definition

Answer 15

A type of pollution that is a mixture of smoke and fog.

Question 16

sustainable

definition

Answer 16

An activity which does not consume or destroy resources or the environment.

Question 17

Biodiversity in different areas

Answer 17

Areas like tropical rainforests have millions of different species and are very biodiverse. Other areas like the Polar Regions have far fewer species and are less biodiverse.

Question 18

Ecosystems with high diversity

Answer 18

Ecosystems with higher biodiversity have fewer species that depend on just one other for food, shelter and maintaining their environment.

Question 19

We are slowly realising that the future of our species on Earth depends on maintaining high biodiversity. There are a number of reasions for this:

Answer 19

• Maintaining important biological resources such as food and medicines - we rely on many different species as food or sources of medicine so it is important to the health of future generations that organisms that supply us with these resources are not lost. This is an example of the importance of biodiversity on a global scale.
• For recreation and tourism - for example, forests with a high biodiversity are attractive places to visit. They benefit local people who use the ecosystem for recreation. It also provides an income to many by attracting other people to the area. This shows why local biodiversity is important.
• Activities that create air and water pollution, are reducing biodiversity in many ecosystems - conservation of species and habitats by charities, governments and individuals helps to maintain the range of biodiversity. 

Question 20

Reasons why our populations increase:

Answer 20

• better health care so people are living longer
• new medicines are being developed so people don’t die of previously fatal diseases
• farmers are able to produce more food using new breeds and equipment

Question 21

Waste management

Population

Answer 21

As the human population increases, the volume of waste and pollution that is produced also increases. Polluting an ecosystem harms or kills the organisms that live within it.

Question 22

Waste management

Consumption

Answer 22

Modern society is more consumable, which means humans manufacture more products and replace them more often. This consumption is not sustainable. Many natural materials, including fossil fuels, will soon run out and scientists argue that there is already too much waste.

Question 23

Water pollution

open sewers

Answer 23

In some parts of the world, open sewers can lead into water courses, such as streams and rivers, which can cause serious illness in humans that may drink the contaminated water.

Question 24

Water pollution

Excessive fertiliser use

Answer 24

Some farmers use too many fertilisers, which can run off fields during heavy rain. This can pollute nearby streams and rivers leading to eutrophication. Some water pollution even comes from toxic chemicals released illegally by factories.

Question 25

The process of eutrophication

step by step

Answer 25

1) Nutrient load up: excessive nutrients from fertilisers are flushed from the land into rivers or lakes by rainwater.
2) Plants flourish: these pollutants cause aquatic growth of algae, duckweed and other plants.
3) Algae blooms, oxygen is depleted: algae blooms, preventing sunlight reaching other plants. The plants die and oxygen in the water is depleted
4) Decomposition further depletes oxygen: dead plants are broken down by bacteria decomposers, using up even more oxygen in the water.
5) Death of the ecosystem: oxygen levels reach a point where no life is possible. Fish and other organisms die.

Question 26

Air pollution

Answer 26

Combustion of fossil fuels and other fuels releases carbon dioxide. This contributes to the greenhouse effect and leads to global warming. It also releases sulfur dioxide and nitrogen oxides which can cause acid rain. Air pollution can also be caused by tiny particulates from smoke which can cause smog. Some of the world’s major cities like Delhi in India and Karachi in Pakistan have dangerously high levels of air pollution.

Question 27

Land pollution

Answer 27

The rubbish we throw out that is not recycled goes into a land fill. These are huge holes in the ground into which our rubbish is dumped. Some things like batteries cannot be put into landfill sites because of the toxic chemicals they contain. They must be recycled. Other land pollution comes when some people dump rubbish in public or other private places, often to avoid paying for it to be disposed of. This is caused fly tipping and is illegal.

Question 28

Land use

expanding population

Answer 28

The larger the human population gets, the more land we require. More houses must be built, more resources found, more food must be grown and more waste is produced. This often means less space and fewer resources for other animals and plants.

Question 29

Land use

biodiversity

Answer 29

Often biodiversity is significantly reduced when land is cleared for human uses, such as building, quarrying, farming and waste disposal. Think about the reduction in biodiversity, which occurs when an area of rainforest is cut down to grow crops.

Question 30

Deforestation

why?

Answer 30

For thousands of years humans have been deforesting small areas of woodland to build their own houses or grow crops to feed their families. However, in recent years the increase in the human population and development of industrial machinery has meant that much larger areas have been cleared. This is often by large companies who deforest to provide land for cattle, rice fields and growing crops for biofuels.

Question 31

What is conservation

Answer 31

Conservation is the preservation of ecosystems and the organisms that live within them.

Question 32

Conservation

Why?

Answer 32

The increase in the human population and waste it produces, deforestation, peat bog destruction and global warming are all reducing biodiversity. Conservation helps reverse this. Conservation is the preservation of ecosystems and the organisms that live within them.

Question 33

Scientists and concerned members of the public help maintain biodiversity by:

Answer 33

• breeding programs to help preserve endangered species, like the panda
• protection and development of new endangered habitats, often by making National Parks
• replanting hedgerows because there is higher biodiversity in them than the fields they surround
• reducing deforestation and the release of greenhouse gases
• reforestation planting trees to replace those cut down
• recycling rather than dumping waste in landfill sites

Question 34

How human interactions within and ecosystem effect biodiversity

Answer 34

Human interactions within the ecosystem may have a positive impact on biodiversity such as conservation or a negative affect such as eutrophication. Negative effects include reduced populations, reduced biodiversity or extinction.

Question 35

Positive effect of human interaction within the ecosystem

Answer 35

Conservation

Question 36

Negative effect of human interaction within the ecosystem

example

Answer 36

• reduced populations
• reduced biodiversity
• extinction

Question 37

Overuse of fertilisers can cause eutrophication and reduce biodiversity

Answer 37

As the human population increases, we need more food and increased use of fertilisers has impacted on the biodiversity of aquatic environments through eutrophication. Nitrates in the fertilisers run off from fields into rivers and lakes causing the overgrowth of algae. The light is blocked so plants cannot photosynthesise so they die. This causes bacteria to decompose the plants and use up most of the oxygen in the water. Without oxygen, animals such as fish will die. This is a negative impact as the biodiversity of the river or lake will decrease.

Question 38

Ways fish farming can reduce biodiversity

Answer 38

• Fish are farmed in large nets or tanks within lakes or in the sea.
• Farm waste, chemicals, pathogens and parasites are released into the surrounding water, harming other marine life.
• Carnivorous species of farmed fish, such as salmon, need high amounts of protein in their diet. They are often fed on wild fish, reducing their populations.
• Sometimes fish can escape and compete with indigenous wild species and compete for resources, resulting in reduced biodiversity. Predators of the fish such as sea lions can become trapped in the nets and die.

Question 39

Introduction of non-indigenous species can reduce biodiversity

Answer 39

A non-indigenous species does not live in an area and may be introduced by humans for a particular purpose such as removal of pest species or for hunting. However, the new species may out-compete or kill indigenous or naturally occurring species. These may be reduced in number, resulting in reduced biodiversity or maybe extinction.

Question 40

Introduction of non-indigenous species can reduce biodiversity

One example is the introduction of cane toads to Australia.

Answer 40

Cane toads are native to South and Middle America but were introduced into Australia in the 1930s to control pests that ate sugar cane, an important crop.

Question 41

Introduction of non-indigenous species can reduce biodiversity

Since their release, the toad population has grown to over 200 million and spread across the country. They have several impacts on biodiversity:

Answer 41

the cane toads are poisonous to animals that eat it, reducing the number of predators
the toad eat insects, reducing their population
it competes with native species for food

Question 42

What is the range of plants and animals in an ecosystem known as?

Answer 42

Biodiversity

Question 43

What is meant by the term extinction?

Answer 43

Extinction is when a species is wiped out forever.

Question 44

What does deforestation mean?

Answer 44

Deforestation is cutting trees down to provide land for other uses.

Question 45

What does deforestation lead to?

Answer 45

Reduced number of habitats and decreased biodiversity

Question 46

Why is the human population growing each year?

Answer 46

The human population is growing because there are more births than deaths.

Question 47

What happens to the oxygen levels during eutrophication?

Answer 47

Oxygen levels in the river or lake will decrease due to the bacteria using it up.

Question 48

Deforestation followed by burning of the trees will release which gas into the atmosphere?

Answer 48

Carbon dioxide