Environmental interactions - 4th form Flashcards

Question

what are trophic levels

Answer 1

the stages in a food chain (or web)

Answer 2

producers consumers

Answer 3

first = primary consumer second = secondary consumer third = tertiary consumer

Answer 4

they are vital for recycling nutrients

Answer 5

it is particularly useful for understanding the links between the species in a community

Answer 6

to represent the relative amounts of organisms at each trophic level - they are always drawn to scale

Answer 7

these are drawn to show the number of each organism counted in the ecosystem. they can be odd shapes due to the different masses of organisms

Answer 8

these are drawn to show the total mass of the organisms in each trophic level (i.e the mass of an individual x the number of individuals). these are a more accurate way of looking at the relative amounts of organisms

Answer 9

kilojoules

Answer 10

kilojoules per square metre per year - kJ/m^2/ year

Answer 11

these are drawn to show the total energy available in each trophic level per square metre per year. there should be a decrease in energy between each trophic level

Answer 12

from light energy to the producer

Answer 13

- some light will miss the plant or the plants chloroplast - some light will be reflected by the cuticle - some light has the wrong wavelength to be absorbed by the chlorophyll

Answer 14

approximately 10%

Answer 15

-some parts of the organisms are not eaten (so the biological molecules are not available are not available for respiration) - some parts are not digested and absorbed - they are egested as faeces (so the biological molecules are not available are not available for respiration) - some materials are respired to release energy - the energy is used for: -- muscle contraction (such as movement and breathing) -- maintaining a constant body temperature (in mammals and bird) -- synthesising biological molecules (including excretory products) -- movement of molecules (active transport) -- cell division

Answer 16

carbon atoms from carbon dioxide become part of glucose molecules (which is stored as starch) in the plant

Answer 17

a) some of the glucose will be broken down by the plant in respiration. the carbon in the glucose becomes part of the carbon dioxide molecule again, and is released back into the air b) some of the carbon compounds in the plant will be eaten by animals. the animals respire, releasing some of it back into the air as carbon dioxide c) when the plant or animal dies, decomposers (bacteria and fungi) will feed on them. the carbon becomes part of the decomposers' bodies. when they respire they release carbon dioxide into the air again d) fossilation occurs when living things do not decay fully when they die due to the to the conditions in the soil. fossil fuels are then formed over millions of years by a process called 'locking in'. these include coal, oil, natural gas and peat. e) when fossils fuels are burnt (combustion), carbon dioxide is released into the atmosphere

Answer 18

decomposers - they break down the dead remains and release the chemicals and release the chemicals for the plants plants to use again. feeding assimilation pass nitrogen - for example in protein molecules - along food chains

Answer 19

1- nitrogenfixing bacteria in the soil and the roots of legume plants absorb nitrogen and reduce it to make ammonia - this is called nitrogen fixation 2- the ammonia is converted to nitrites and nitrates by the nitrifying bacteria - this is called nitrification 3- plant roots can only absorb the nitrates. they are combined with carbohydrates (from photosynthesis) to form amino acids which are then made into proteins, and nucleotides which are joined to make DNA and RNA 4- animals eat plants. they digest the proteins and DNA, absorbing the small soluble molecules (amino acids and nucleotides). these are used by the animal to synthesise (make) new proteins and DNA (assimilation) 5- when a plant or animal dies its tissues are decomposed by bacteria and fungi (saprotrophic feeding) 6- molecules containing nitrogen such as proteins are broken down by the bacteria and fungi and ammonia is released into the soil 7- some nitrates are converted into N2 by denitrifying bacteria - this process is called denitrification

Answer 20

protein in dead plants and animals is broken down ammonia is released into the soil

Answer 21

decomposing bacteria

Answer 22

ammonia is converted to nitrites, and nitrites are converted into nitrates

Answer 23

nitrifying bacteria

Answer 24

nitrates are converted to nitrogen gas (denitrification reduces the amount of nitrate in the soil and therefore makes the soil less fertile)

Answer 25

denitrifying bacteria

Answer 26

nitrogen gas is converted to ammonia in bacteria which is used to make proteins, when the bacteria die their proteins decompose, releasing ammonia back into the soil

Answer 27

nitrogen-fixing bacteria found in soil and root nodules of plants

Answer 28

in small structures - nodules - on the roots of legume plants. this is a mutualistic relationship - the bacteria receive glucose from the plant, while the plant absorbs ammonia from bacteria in the middle

Answer 29

they make the soil much more fertile by releasing ammonia which can be converted into nitrates. this is why farmers may rotate the crops they grow in each field. they could grow clover but instead they often grow leguminous plants which they can then sell such as peas

Answer 30

radiation which travels through space

Answer 31

travels through space. some is reflected by the earth's atmosphere, but some passes through and is absorbed by the earth's surface - this warms the earth , which then emits infra-red (IR) radiation

Answer 32

some IR radiation passes through the atmosphere into space, but some gases in the atmosphere absorb the IR radiation, preventing it from escaping back into space. this leads to more energy being held by the atmosphere, heating it.

Answer 33

water vapour, carbon dioxide, methane, nitrous oxides and CFCs

Answer 34

without it the entire planet would be frozen

Answer 35

enhanced greenhouse effect

Answer 36

burning fossil fuels slash and burn forest clearance

Answer 37

generated by bacteria in anaerobic conditions such as: -- ruminants such as cattle produce large volumes of methane from the anaerobic activity of bacteria in their gut -- this largely comes out from their mouths -- bacteria is waterlogged paddy fields for rice cultivation give off methane

Answer 38

burning fossil fuels

Answer 39

until the 1990's CFCs were used as a solvent for aerosols such as deodorants + they were also used in fridges and freezers CFCs were also blamed for the hole in the ozone layer

Answer 40

melting of polar ice caps destruction of habitats drought and desertification increased extreme weather events spread of disease change in crops increase in heat related illness and deaths

Answer 41

if ice shelves over land melt, such as over Greenland and Antarctica, this will lead to sea level rises, causing flooding in coastal regions worldwide

Answer 42

for example grassland may turn to desert (desertification), leading to the loss of habitat for resident species - this could lead to the extinction of species

Answer 43

can lead to crop failure and therefore to food shortages and famines

Answer 44

extreme weather events such as hurricanes could become more frequent as there is more energy present in weather systems due to global warming

Answer 45

as the planet warms it will be possible for disease carrying organisms, such as mosquitos, to survive in a wider range of countries. this means diseases such as malaria and dengue fever are likely to become more common

Answer 46

as areas warm it will become possible to grow different crops (e.g olives and grapes in southern England) - this will be beneficial to some countries

Answer 47

in recent years there have been increases in death rates in elderly associated with heat waves - this may become more common