unit 16

Question 1

population

Answer 1

total number of organisms of the same species living in the same geographical area

Question 1

community

Answer 1

populations of all of the different species that live in the same habitat

Question 2

biotic

Answer 2

living parts of environment

Question 3

abiotic

Answer 3

non living parts of environment

Question 4

ecosystem

Answer 4

abiotic and biotic parts of an environment and how they interact

Question 5

what do plants need

Answer 5

light, space, water and mineral ions from the soil

Question 6

what do animals need

Answer 6

space, territory, food, water and mates

Question 7

interdependence

Answer 7

all of the diff species in a community depend on eachother for food,shelter, pollination and if one species is removed it can affect the whole community e.g animals depend of other living organisms for food

Question 8

stable community

Answer 8

populations of the different species remain fairly constant

Question 9

abiotic factors( non living factors that can affect a community)

Answer 9

-light intensity
-temperature
-moisture levels
-soil PH and mineral content
-wind intensity and direction
-co2 levels for plants
-oxygen levels for aquatic animals

Question 10

biotic factors(living factors which can affect a community)

Answer 10

• availability of food
  -new predators arriving
  -new pathogens
  -one species outcompeting another so the numbers and no longer sufficient to breed

Question 11

adaptations and types

Answer 11

features that enable organisms to survive in the conditions in which they normally live
types:
-functional
-structural
-behavioral

Question 12

extremophiles

Answer 12

organisms that live in environments that are very extreme. e.g high temps, pressure, salt concentration. (bacteria living in deep sea vents)

Question 13

how can feeding relationships within a community be represented?

Answer 13

by food chains

Question 14

what do producers do in food chains

Answer 14

synthesize molecules. (green plant/algae making glucose by photosynthesis)

Question 15

why are a range of experimental methods using transects and quadrats used by ecologists?

Answer 15

to determine the distribution and abundance of species in an ecosystem

Question 16

what happens in a stable community?

Answer 16

the numbers of predators and prey rise and fall in cycles

Question 17

why are all materials in the living world recycled?

Answer 17

to provide the building blocks for future organisms

Question 18

what happens in the carbon culce

Answer 18

carbon is returned from organisms to the atmosphere as co2 to be used to by plants in photosynthesis

Question 19

what happens in the water cycle?

Answer 19

fresh water is provided for plants and animals on land before draining into the seas. Water is continuously evaporated and precipitated.

Question 20

what factors affect the rate of decay of biological material

Answer 20

• temp
  -water availability
  -oxygen

Question 21

why do farmers/ gardens provide optimum conditions for rapid decay of waste biological material?

Answer 21

they want the compost that is produced bc can be used as a natural fertilizer for growing garden plants or crops

Question 22

what type of decay produces methane gas?

Answer 22

anaerobic decay

Question 23

Biogas generators can be used to produce … as a fuel

Answer 23

methane gas

Question 24

what environmental changes affect distribution of species in an ecosystem?

Answer 24

-temp
-availability of water
-composition of atmospheric gases

Question 25

biodiversity

Answer 25

the variety of all the different species of organisms on Earth of within an ecosystem

Question 26

what does a great biodiversity ensure?

Answer 26

the stability of ecosystems by reducing the dependence of one species in another for food,shelter and the maintenance of the physical environment.

Question 27

what does the future of the human species on Earth rely on?

Answer 27

us maintaining a good level of biodiversity. many human activities are reducing biodiversity and only recently measure have been taken to stop reduction.

Question 28

what does rapid growth in the human population and increase in standard living mean?

Answer 28

more resources used and more waste produced. Unless waste and chemical materials are properly handled, more pollution will be caused.

Question 29

different ways pollution can occur

Answer 29

-in water, from sewage, fertilizer or toxic chemicals
-in air, from smoke and acidic gases
-on land, from landfill and toxic chemicals

Question 30

how does pollution reduce biodiversity

Answer 30

it kills plants and animals

Question 31

how do humans reduce the amount of land available for other animals and plants

Answer 31

building
quarrying
farming
dumping waste

Question 32

what has large-scale deforestation in tropical areas occurred to?

Answer 32

• provide land for cattle and rice fields
  -grow crops for biofuels

Question 33

global warming

Answer 33

levels of co2 and methane in atmosphere are increasing contributing to it

Question 34

how humans can reduce the negative effects on evosystems

Answer 34

• breeding programs for endangered species
• protection and regeneration of rare habitats
  -reintroduction of field margins and hedgerows in agricultural areas where farmers only grow one type of crop
• reduction of deforestation and carbon dioxide emissions by some governments
  -recycling resources rather than dumping waste in landfill

Question 35

trophies levels

Answer 35

level 1: plants and algae make their own food and are called producers
level 2: herbivores eat plants/algae and called primary consumers
level 3: carnivores that eat other carnivores afe tertiary consumers

Question 36

apex predators

Answer 36

carnivores with no predators

Question 37

what do decomposers do?

Answer 37

break down dead plant and animal matter by secreting enzymes into the environment. Small soluble food molecules then diffuse into the microorganism

Question 38

transfer of biomass

Answer 38

plants/ algae transfer 1% if incident energy from light for photosynthesis

10% of the biomass from each tropic level transferred to level above.

Question 39

what is loss of biomass due to?

Answer 39

• not all the ingested material is absorbed, some is egested as faeces
• some absorbed materials is lost as waste. e.g co2 and water in respiration and water and urea in urine.

Question 40

biological factors threatening food security

Answer 40

-the increasing birth rate has threatened food security in some countries.
-changing diets in developed countries means scarce food resources are transported around the world.
-new pests and pathogens that affect farming
- environmental changes that affect food production e.g widespread famine occurring in some counties if rains fail.
-the cost of agricultural inputs
-conflicts risen affect food/ water availability.

Question 41

how can efficiency of food production be improved?

Answer 41

restricting energy transfer from food animals to the environment.
-limiting their movement
-controlling temp of their surroundings
-some fed high protein doods