B3

Question 0

Why do species adapt to their environment?

Answer 0

They are more likely to survive and reproduce

Question 1

Define Species

Answer 1

A species is a group of organisms that can breed together to produce FERTILE offspring

Question 2

Individuals of the same species will all be slightly different. What are these differences called?

Answer 2

Variation. Some of this is genetic and so passed on to offspring

Question 3

One of the causes of genetic variation is when genes change. What causes this change?

Answer 3

Mutations.

Question 4

Why do mutations occur?

Answer 4

They can be caused by outside factors such as radiation/chemicals and my mistakes when genes are copied during cell division

Question 5

Mutations can occur in body cells but they have little or no effect. What happens of they occur in the formation of sex cells?

Answer 5

They have more effect because the mutation will then be passed on to all the cells of the offspring causing the offspring to develop new characteristics, this can be harmful but it might actually help them survive

Question 6

What is the process that causes evolution?

Answer 6

Natural selection

Question 7

Explain natural selection

Answer 7

Living things have variation. The resources they need are limited and they must compete for these resources. Only some will survive. These varieties will have a better chance of survival causing them to have a greater chance of reproducing and passing the characteristics onto their offspring. Now a greater proportion have this characteristic and over many generations the specifies become more able to survive

Question 8

What is selective breeding?

Answer 8

This is where humans deliberately choose a feature they want to appear in the next generation. Unlike natural selection, which only selects features that help survival, selective breeding may promote features that don’t help survival eg. Cows that produce the lost milk

Question 9

When did life on Earth begin?

Answer 9

3500 million years ago

Question 10

What evidence is there for evolution?

Answer 10

Fossil records and DNA

Question 11

How does DNA prove evolution?

Answer 11

It controls the characteristics of living things. It mutates and changes over time. All living things have similarities within their DNA as you expect if they have all evolved from the same simple life forms. The more closely related two species are, the more similar their DNA is. Scientists can use these similarities/differences to work out how life has evolved

Question 12

Who proposed the theory of evolution by natural selection by making many observations of organisms and applying creative thought to his findings?

Answer 12

Charles Darwin

Question 13

Who was Lamarck?

Answer 13

A French man who thought differently about evolution. He said that acquired characteristics could be passed onto offspring (eg. Rabbits passing on big leg muscles from running)

Question 14

Why did people believe Darwin and not Lamarck?

Answer 14

Because people realised that acquired characterises don’t have a genetic basis so they’re unable to be passed onto the next generation

Question 15

What is biodiversity?

Answer 15

The variety of life on Earth including the number of species, range of organisms and the genetic variation

Question 16

Why is biodiversity important?

Answer 16

The more plants we have available, the more resources there are for developing new food crops, many medicines have been discovered using chemicals produced by living things. When an organism becomes extinct, the unique chemicals become unavailable

Question 17

What is causing the rate of extinction to increase?

Answer 17

HUMANS!

Question 18

Why isn’t nitrogen used by animals and plants directly, but why do they still need it?

Answer 18

It is very un reactive, but it is needed for making proteins so plants and animals must get it somehow

Question 19

How do plants get their nitrogen?

Answer 19

They get it from the soil but it has to be turned into nitrates so they can use it to make proteins

Question 20

How do animals get proteins?

Answer 20

By eating plants (or other animals)

Question 21

What is nitrogen fixation and how does it happen?

Answer 21

The process of turning N2 from the air into nitrogen compounds in the soil which plants can then use. This can occur through the energy in lightning causing the soil to react with the oxygen in the air to give nitrates or nitrogen fixing bacteria in roots and soil

Question 22

What are decomposers?

Answer 22

They break down proteins in dead plants and animals and urea in excreted animal waste into ammonia. Ammonia is turned into nitrates by denitrifying bacteria in the soil

Question 23

Name the four different types of microorganisms in the nitrogen cycle

Answer 23

Decomposers (decompose proteins and urea and turn them into proteins), denitrifying bacteria (turn nitrates back into N2 gas), nitrogen-fixing bacteria (turn N2 into nitrogen compounds that plants can use), nitrifying bacteria (turn ammonia in decaying matter into nitrates (nitrification))