SB9 - Ecosystems and Material Cycles Flashcards

Question

Give an example of how biotic factors can affect an ecosystem.

Answer 1

In Yellowstone National Park, wolves has been the top predator until 1926, when they became extinct due to hunting. After that, the number of elk increased rapidly. Their huge numbers caused overgrazing if tree species, which left little food for other herbivores, including beavers. The number of coyotes also increased due to lack of competition for young elk.in 1995, grey wolves were reintroduced to Yellowstone, increasing the predation of elk. This led to an increase in beaver numbers, which created pools and muddy areas (as beavers build dams). These new habitats allowed more species to grow, increasing the biodiversity.

Answer 2

The number of different species in an area.

Answer 3

When the numbers of a predator and its prey are closely correlated (as numbers of one increase, numbers of the other increase and vice versa).

Answer 4

The presence or absence of a particular species form an area can give information about the level of pollution in that area.

Answer 5

Different species of lichen are different levels of resistant to pollution, meaning the type of lichen present on a particular area can indicate the pollution level in that area.

Answer 6

Blackspot fungus is a pathogen of roses. The fungus cannot grow well where there is a lot of sulphur pollution, so roses in cities rarely suffer from blackspot.

Answer 7

- fertilisers - sewage - poisonous substances released by factories (such as mercury or detergents)

Answer 8

Stonefly nymph dragonfly nymph freshwater shrimp water louse bloodworm sludgeworm —————> increasing pollution levels

Answer 9

A feeding relationship where one organism (the parasite) benefits by feeding off a host organism, causing harm to the host.

Answer 10

Tapeworms, lice, gordian worm, ticks, roundworms, leeches, fleas

Answer 11

Where multiple organisms live in the same habitat and both benefit from a relationship with the other.

Answer 12

Many flowers depend on insects for pollination. The flower benefits by being able to produce fertilised egg cells, and the insect benefits by collecting nectar or pollen from the flower, which it uses for food.

Answer 13

When lots of fish are bred in a small space to produce more fish to meet global demand.

Answer 14

Fish farming causes the changing of the conditions for native species, for example, due to waste and uneaten food sinking to the bottom of the water. Parasites and disease spread easily between the fish in owns, so the fish need to be treated to keep them healthy. However, they can still pass the disease on to native species. Also, this can lead to antibiotic resistance.

Answer 15

It prevents overfishing of fish and so preserves stocks of wild fish. It can also produce enough fish to meet the increasing global demand.

Answer 16

An indigenous species is native to the area, whereas a non-indigenous species is not native to the area, it has been introduced from somewhere else.

Answer 17

Sometimes, non-indigenous species are introduced to be grown for food (e.g. soybeans are native to Asia but are grown in many parts of the world for food). Sometimes, non-indigenous species are introduced as a form of biological control (e.g. Australia introduced the cane toad to try and control levels of cane beetles, which were eating the sugar cane crops, however the acne toad soon became an invasive species as they are poisonous and kill native animals).

Answer 18

The addition of more nutrients to an ecosystem than it normally has.

Answer 19

When farmers use too much fertiliser, it doesn’t get absorbed by the crops and when it rains, the excess fertiliser enters lakes as runoff. Leaching through the ground can also cause eutrophication.

Answer 20

- fertiliser is added to a field and enters a lake as runoff - high nitrate and phosphate concentrations in the water encourage plants and algae to grow rapidly - surface plants (algae) grow rapidly and block sunlight, causing the death of the plants below them, which stop producing oxygen by photosynthesis - decomposing bacteria increase in numbers and and use up more oxygen from the water - the oxygen concentration of the water decreases - aquatic animals such as fish die due to lack of oxygen

Answer 21

When an effort is made to protect a rare or endangered species or habitat

Answer 22

- preserves individual species and communities - areas with greater biodiversity can recover faster from natural disasters like flooding - we can use plants and animals as a source of medicines and other products

Answer 23

There are many ways to do this, for example, reforestation projects can create more diverse habitats, which cause a greater variety of species to migrate to the area. Also, reintroducing native species can work, for example the reintroduction of grey wolves to Yellowstone National Park increased biodiversity.

Answer 24

Food security is having enough safe and healthy food at all times.

Answer 25

Changing farming practices (e.g. eating farmed rather than wild fish) may help. Also eating more vegetables rather than meat may help. Agricultural inputs (such as fertilisers) can help food security as they increase yields.

Answer 26

The process by which water is recycled through organisms and the environment (abiotic and biotic components) to support life.

Answer 27

- energy from the Sun evaporates water from oceans, lakes, seas etc. - the water cools as it rises, and condenses to form water vapour, which forms clouds - as the water droplets get too large or heavy, they fall as rain, snow or hail (precipitation) - the water is returned to the ocean through surface runoff and leaching - some water goes straight back to the air by transpiration

Answer 28

The process of obtaining fresh water from the sea of salty water. Several methods are used to do this, such as distillation, where the water is evaporated then condensed and collected.