4- ecology and the environment

Question 1

population

Answer 1

a group of organisms of the same species living in the same place at the same time

Question 2

community

Answer 2

all of the populations living in the same area at the same time

Question 3

habitat

Answer 3

where an organism lives

Question 4

ecosystem

Answer 4

all the biotic factors and all the abiotic factors that interact within an area at one time

Question 5

quadrats

Answer 5

Quadrats are square frames made of wood or wire
They can be a variety of sizes eg. 0.25m2 or 1m2
They are placed on the ground and the organisms within them are recorded
Plants species are commonly studied using quadrats to estimate the abundance

Question 6

quadrats can be used to measure abundance by recording

Answer 6

The number of an individual species: the total number of individuals of a single species (eg. buttercups) is recorded
Species richness: the total number of different species (but not the number of individuals of each species) is recorded
Percentage cover: the approximate percentage of the quadrat area in which an individual species is found is recorded (this method is used when it is difficult to count individuals of the plant species being recorded eg. grass or moss

Question 7

apparatus needed to investigate population size in 2 different areas using quadrats

Answer 7

2 tape measures
Quadrat
Random number generator
Species key

Question 8

method to investigate population in size in 2 different areas using quadrats

Answer 8

1) take a tape measure to lay out in a survey area in the chosen habitat
2) use a random number generator and create a list of coordinates to place your first quadrant
3) count the number of your chosen plant species that are found within this quadrat
4) estimate the population of dandelions in your survey areas using this equation: (total area/ area sampled) x total number of plants counted

Question 9

results of investigating population in size in 2 different areas using quadrats

Answer 9

Once the results have been collected and the averages calculated, we can compare the abundance of the study species in each survey area
Species abundance is likely to be influenced by biotic factors such as:
Competition
Predator-prey relationships
Interactions with other organisms within the food chain or food web
The abundance will also be influenced by abiotic factors such as:
Light intensity
Mineral availability
Water availability
pH
Temperature
Salinity

Question 10

limitations to investigating population in size in 2 different areas using quadrats

Answer 10

It can be easy to miss individual organisms when counting in a quadrat, especially if they are covered by a different species
Solution: Use a pencil or stick to carefully move leaves out of the way to check if there is anything else underneath
Identifying species may be tricky
Solution: Use a species key to identify the species

Question 11

corms to investigate population in size in 2 different areas using quadrats

Answer 11

C - We are changing the study area where we are collecting the data
O - We will count the same species of organism in each quadrat
R - We will repeat the investigation several times to ensure reliability
M - We will count the number of the designated study species found across all quadrats
S - We will control the size of the quadrat, the random way that quadrats are placed on the ground, the day that the results were collected

Question 12

abiotic

Answer 12

non living

Question 13

biotic

Answer 13

living

Question 14

an abiotic factor is

Answer 14

a non living factor within an environment such as temperature, light intensity and wind speed

Question 15

light intensity affect on community

Answer 15

LIGHT IS NEEDED BY PLANTS FOR
PHOTOSYNTHESIS. MORE LIGHT LEADS TO
AN INCREASE IN RATE OF PHOTOSYNTHESIS
AND AN INCREASE IN PLANT GROWTH RATE

Question 16

temperature affect on community

Answer 16

AFFECTS THE RATE OF PHOTOSYNTHESIS

IN PLANTS

Question 17

moisture levels affect own community

Answer 17

PLANTS AND ANIMALS REQUIRE WATER

TO SURVIVE

Question 18

soil pH and mineral content affect on community

Answer 18

DIFFERENT SPECIES OF PLANTS ARE
ADAPTED TO DIFFERENT SOIL pH LEVELS
AND NUTRIENT CONCENTRATION LEVELS

Question 19

wind intensity and direction affect on community

Answer 19

WIND SPEED AFFECTS TRANSPIRATION
RATE IN PLANTS. TRANSPIRATION AFFECTS
THE RATE OF PHOTOSYNTHESIS AS IT
ENSURES WATER AND MINERAL IONS ARE
TRANSPORTED TO THE LEAVES

Question 20

carbon dioxide levels for plants affect on community

Answer 20

CO, IS REQUIRED FOR PHOTOSYNTHESIS IN
PLANTS. CO CONCENTRATION AFFECTS
THE RATE OF PHOTOSYNTHESIS

Question 21

oxygen levels for aquatic animals affect on community

Answer 21

SOME AQUATIC ANIMALS (SUCH AS FISH)
CAN ONLY SURVIVE IN WATER WITH HIGH
OXYGEN CONCENTRATIONS

Question 22

availability of food affect on community

Answer 22

MORE FOOD MEANS
ORGANISMS HAVE A
HIGHER CHANCE OF
SURVIVING AND
REPRODUCING. THIS
MEANS THEIR
POPULATIONS CAN
INCREASE

Question 23

new predators affect on community

Answer 23

IN BALANCED
ECOSYSTEMS,
PREDATORS CATCH
ENOUGH PREY TO
SURVIVE BUT NOT SO
MANY THAT THEY WIPE
OUT THE PREY
POPULATION. IF A NEW
PREDATOR ISI
NTRODUCED TO THE
ECOSYSTEM. IT MAY
BECOME UNBALANCED

Question 24

new pathogens affect on community

Answer 24

if a new pathogen enters an ecosystem the populations living there will have no immunity or resistance to it and the population may decline or be wiped out

Question 25

competition affect on community

Answer 25

``` IF TWO SPECIES COMPETE FOR THE SAME RESOURCE(S) AND ONE IS BETTER ADAPTED TO TAKE ADVANTAGE OF THESE RESOURCES, THEN THAT SPECIES WILL OUTCOMPETE THE OTHER. THIS MAY CONTINUE UNTIL THERE ARE TOO FEW MEMBERS OF THE LESSER ADAPTED SPECIES TO BREED SUCCESSFULLY ```

Question 26

trophic levels are used to

Answer 26

describe the feeding relationships between organisms

Question 27

producers

Answer 27

produce their own organic nutrients usually using energy from sunlight

Question 28

primary consumers

Answer 28

herbivores- feed on producers

Question 29

secondary consumers

Answer 29

predators that feed on primary consumers

Question 30

tertiary consumers

Answer 30

predators that feed on secondary consumers

Question 31

food chain-

Answer 31

Producer: food chains always begin with a producer Primary consumer: producers are eaten by primary consumers (herbivores/omnivores) Secondary consumer: primary consumers are eaten by secondary consumers (carnivores/omnivores) Tertiary consumer: secondary consumers are eaten by tertiary consumers (carnivores/omnivores)

Question 32

a food chain shows

Answer 32

the transfer of energy from one organism to the next

Question 33

the source of all energy in a food chain is

Answer 33

light energy from the sun

Question 34

the arrows on a food chain show

Answer 34

the transfer of energy from one trophic level of the food chain to the next

Question 35

in order for energy to be passed on it has to be

Answer 35

consumed

Question 36

a food web is

Answer 36

a network of interconnected food chains

Question 37

food webs show

Answer 37

interdependance- how the change in one population can affect others within the food web

Question 38

a food pyramid of numbers shows

Answer 38

how many organisms we are talking about at each level of a food chain

Question 39

the width of a food pyramid indicates

Answer 39

the number of organisms at that trophic level

Question 40

a pyramid of biomass shows

Answer 40

how much mass the creatures at each level would have without including all the water that is in the organism

Question 41

how much energy of each trophic level is actually transferred

Answer 41

10%

Question 42

losses of energy are due to

Answer 42

Organisms rarely eat every part of the organism they are consuming – some of the biological material of plants and animals may be inedible (eg. many predators do not consume the bones of their prey) Not all the ingested material is digested and absorbed, some is egested as faeces Energy is used for movement Energy is used to generate heat Energy is used for metabolic processes Some absorbed material is lost as waste: Carbon dioxide and water are waste products of respiration Water and urea are the waste products in the urine, which is produced when proteins are broken down

Question 43

describe the carbon cycle

Answer 43

Carbon is taken out of the atmosphere in the form of carbon dioxide by plants to be used for photosynthesis It is passed on to animals (and microorganisms) by feeding It is returned to the atmosphere in the form of carbon dioxide by plants, animals and microorganisms as a result of respiration If animals and plants die in conditions where decomposing microorganisms are not present the carbon in their bodies can be converted, over millions of years and significant pressure, into fossil fuels When fossil fuels are burned (the process is known as combustion), the carbon combines with oxygen and carbon dioxide is released into the atmosphere Increased use of fossil fuels is contributing to an increase in the carbon dioxide content of the atmosphere In addition, mass deforestation is reducing the amount of producers available to take carbon dioxide out of the atmosphere by photosynthesis This problem is exacerbated by the fact that in many areas of the world, deforestation is taking place for land rather than for the trees themselves, and as such they are burnt down, releasing yet more carbon dioxide into the atmosphere

Question 44

biological consequences of sulphur dioxides and nitrogen oxides

Answer 44

``` Combustion of fossil fuels that contain sulphur impurities creates sulphur dioxide. Nitrogen oxides are also produced during fossil fuel combustion. These gases react with oxygen and dissolve in rainwater to produce dilute sulphuric acid and nitric acid, which leads to acid rain. ```

Question 45

greenhouse gases

Answer 45

``` Water vapour Carbon dioxide Methane Nitrous oxides CFCs ```

Question 46

human activities that contribute to increasing levels of carbon dioxide and methane

Answer 46

Carbon dioxide is produced during the combustion of fossil fuel Methane is produced by cattle as they digest grass and released by rice paddy fields

Question 47

the greenhouse affect

Answer 47

The Sun emits rays that enter the Earth’s atmosphere The heat bounces back from the Earth’s surface Some heat is reflected back out into space Some heat is absorbed by greenhouse gases and is trapped within the Earth’s atmosphere – this is normal However, as the levels of greenhouse gases in the atmosphere rise due to human activities the Earth’s average temperature rises beyond normal (an enhanced greenhouse effect), causing global warming

Question 48

consequences of global warming

Answer 48

Ocean temperatures increasing, causing melting of polar ice caps / rising sea levels / flooding / coral bleaching Increasing temperatures causing extreme weather like super storms, flooding, droughts Changes in or loss of habitats due to these extreme weather events Decreases in biodiversity as food chains are disrupted and extinction rates increase Increases in migration of species to new places, including increased spread of pests and disease