biology life on earth (2)

Question 0

Mutagenic Agents

Answer 0

X-rays, UV light, mustard gas

Question 1

Mutations

Answer 1

A random change in the genetic composition of a cell. They can be caused from errors when replicating DNA and from mutagenic agents.

Question 2

Neutral mutations

Answer 2

Have no effect on the organism e.g. Kinky tails in mice

Question 3

Advantageous mutations

Answer 3

Benefit the organism e.g. Sickle cell anaemia gives immunity to malaria

Question 4

Disadvantageous mutations

Answer 4

Have a negative effect on the organism e.g. Widow tadpoles

Question 5

Variation

Answer 5

Occurs as a result of mutations that create new forms of genes called alleles, which can be inherited by the next generation.

Variation is the slight difference in genetic code that each individual member of a species has

Question 6

Variation within a population

Answer 6

Makes it possible for a population to evolve over time in response to an environmental change

Question 7

Adaptation

Answer 7

An inherited characteristic that makes an organism well suited for survival in its environment

Question 8

Adaptations in camels for the desert

Answer 8

Stretchy nostrils to keep out sand, long eyelashes to keep sand out of eyes, hump for storing food, hair I’m back to protect from sun, padded feet to protect from heat of ground, long legs keep it far from the hot ground, leathery mouth helps it eat spiky plants

Question 9

Adaptations can be:

Answer 9

Anatomical
Physiological
Behavioural

Question 10

Selective advantageous organisms

Answer 10

Those that have inherited genes to help them survive e.g. Avoiding predation, competing for food, resisting disease, these are then passed on through reproduction as the advantageous organisms survive

Question 11

Natural selection

Answer 11

Allows species to respond to changes in the environment
Well-adapted individuals which are selectively advantageous survive and reproduce passing on the genes that make them well adapted

Question 12

Light peppered moths

Answer 12

Moths became darker as pollution killed lighter lichen revealing a darker tree beneath, dark moths then had a greater chance of reproducing and passing on the alleles that made them dark, this meant that moths became darker in industrial areas

Question 13

Species

Answer 13

A group of organisms able to interbreed and produce fertile offspring

Question 14

Speciation

Answer 14

Groups from a population become isolated from each other by barriers that prevent exchange of genes. Mutation then occurs and then natural selection. If the barrier is removed after a long period of time the species will not be able to interbreed and produce fertile offspring so are now different species

Question 15

Innate behaviour

Answer 15

Behaviours that are passed on from one generation to the next through the genes, coded for by genes and not learned through observation

Question 16

Learned behaviour

Answer 16

Not passed down by genes but must be learned by an animal during its lifetime, it does this by observing other animals e.g. Swarming, migration, communication

Question 17

Human impact on the environment

Answer 17

The increasing human population has increased the need for food, this has resulted in farmers using technique such as intensive farming and monoculture to increase food yield

Question 18

Fertiliser use

Answer 18

Used in intensive farming to provide plants with the minerals they need for growth to increase food yield, chemical or natural fertilisers can be used

Question 19

Fertiliser minerals

Answer 19

Nitrogen, phosphorus, potassium, magnesium

Question 20

Importance of fertilisers

Answer 20

When crops are harvested elements like nitrogen are removed and fertilisers are used to replace them allowing more crops to grow

Question 21

Nitrogen cycle

Answer 21

The natural process of nitrogen recycling in the environment.
REVISE DIAGRAM OKAY

Question 22

Pesticides

Answer 22

Used in intensive farming to control, kill or deter pests, they are sprayed onto crops directly

Question 23

Bioaccumulation

Answer 23

As pesticides such as DDT are passed along a food chain they increase in toxicity and can reach fatal levels

Question 24

Indicator species

Answer 24

Species that indicate the levels of pollution by their absence or presence

Question 25

GM crops

Answer 25

Genetically modified crops are crops that have had their DNA genetically modified using genetic engineering techniques to resist pests and improve the growth of plants

Question 26

Biological control

Answer 26

A method of controlling pests (including insects, mites weeds and plant diseases) by introducing other organisms e.g. Ladybirds to predate greenflies

Question 27

Indicator of high pollution

Answer 27

Sludge worm

Question 28

Indicator of low pollution

Answer 28

Mayfly larva

Question 29

Importance of nitrogen

Answer 29

Creates proteins m8

Question 30

Decomposers

Answer 30

Break down dead animals, plants and waste into ammonium compound

Question 31

Nitrifying bacteria

Answer 31

Turn ammonium compound into nitrites then nitrites into nitrates

Question 32

Denitrifying bacteria

Answer 32

Turn nitrates back into nitrogen in the air

Question 33

Nitrogen fixation

Answer 33

Process of nitrogen going from the air to ammonium compound