Chapter Seven - Ecology Flashcards

Question

Why might countries suffering from famine only have one consumer?

Answer 1

Less chance for energy to be lost | E.g rice --> human

Answer 2

A key process in the recycling of carbon and nitrogen. The decay process releases the nutrients back into the soil. The bacteria and fungi responsible for this recycling feed on dead plant and animal material as well as waste materials released by egestion and excretion of animals.

Answer 3

A measure of the range of different species of organisms living in an area

Answer 4

The result of decomposition. It is a component of the soil in which plants grow and from which they extract minerals. For this to happen, the bacteria and fungi involved release digestive enzymes on to the material. Following this extracellular digestion (meaning outside the body or cell) the soluble products are absorbed by the organism.

Answer 5

Carbon cycle diagram in page 45 of revision guide.

Answer 6

The amount of c02 in our atmosphere should stay constant but if the amount of respiration and combustion of fossil fuels increases and the amount of photosynthesis decreases (due to deforestation for example) then levels of c02 will increase.

Answer 7

There is a vast amount of scientific research to suggest that human activities have resulted in increased c02 levels which have in turn led to the greenhouse gas effect and global warming. Although there is much evidence to support this theory it should be remembered there are other possible explanations for some of the increase in global temps such as natural variations in temp due to solar activity

Answer 8

Abiotic data used to monitor global warming includes c02 levels, extent and size of polar ice fields, ice density and sea levels. Govts have put in place policies at national and local levels to reduce c02 emissions through placing a greater emphasis on use of renewable energy sources and changes in agricultural practises.

Answer 9

The nitrogen cycle diagram is on page 46 of revision guide. 1. Animals feed on plants and covert plant protein to animal protein. | - death and excretion | - decay bacteria and fungi break down dead plant and animals to | produce ammonia \/ 2. Ammonia | - nitrifying bacteria convert ammonia to nitrate (in process called | nitrification) which can be absorbed by plants \/ 3. Nitrate -->Denitrifying bacteria covert nitrates to nitrogen gas- denitrification occurs mainly in waterlogged soils -->4. Nitrogen in air 3 & 4 | | - nitrogen- fixing bacteria converts nitrogen gas to nitrates | | - nitrogen fixation takes place in root nodules of legumes, the V V plants use the nitrates for growth 5. Plants absorb nitrates and use them to make proteins--> 1.

Answer 10

Magnesium - for making chlorophyll Calcium - for the production of new cell walls Nitrogen - in the from of nitrates for the formation of protein

Answer 11

These are cells with an extended cell wall that increases the surface area for effective absorption of minerals and water.

Answer 12

To improve growth of their crops. Fertilisers can be natural of artificial and argue designed to increase the levels of minerals magnesium, calcium and nitrogen and other minerals.

Answer 13

E.g manure, compost - low cost - release nutrients throughout growing season and do not leach easily - amount of minerals contained in them vary - they can be difficult to store and spread

Answer 14

- more expensive than natural fertilisers - more easily applied to fields - more accurate level of each mineral can be applied - soluble and can leach easily leading to pollution - for food to be labelled organic, only natural fertilisers can be used during growing

Answer 15

The absorption of minerals from the soil relies on a process called active uptake. This process uses energy to move the minerals from low concentration to high concentration (against the concentration gradient). Energy required for active uptake is derived from respiration - oxygen is required. If soil becomes waterlogged oxygen levels are too low goal low sufficient energy to be released. Results in minerals are not being absorbed and poor plant growth.

Answer 16

A form of water pollution and can be the result of sewage entering water ways. It's a problem associated with incorrect use of fertilisers.

Answer 17

Additional nutrients to water from sewage, slurry and fertilisers run-off. | V Leads to increased aquatic plant and algal growth. Many die due to shading | V When algae die they are decomposed by bacteria | V The bacteria use up the oxygen in the water | V Fish and other animals die without oxygen

Answer 18

Combustion of fossil fuels V Sulphur dioxide released V Sulfur dioxide dissolves in water vapour forming sulphuric acid V Water vapour forms clouds that are carried long distances V When rain falls it can cause a range of problems V V V - river and lakes become acidic, can lead to fish poisoning - trees can lose their leaves (defoliation) and therefore die - stonework (statues and buildings) can be corroded

Answer 19

The problems caused by acid rain are often not seen in the country that released the original pollutant as prevailing winds carry the rain clouds long distances before the rain falls. International action is being taken to filter emissions from combustion of fuels and the increased used of renewable energy sources such as wind, solar and hydroelectric power has vastly reduced emissions of gases that cause acid rain.

Answer 20

Indicator species 1. Lichen - simple plants that cannot tolerate air pollution. Their presence on brick, stone and roofing indicates low levels of pollution. They are rarely found in towns and cities where air pollution is high 2. Bloodworms - water-dwelling animals that can only survive when oxygen levels are low. They are therefore good indicators of instances of eutrophication