B2.8

Question 1

What are fossils?

Answer 1

The remains of animals from many years ago

Question 2

Where are fossils found?

Answer 2

In rocks

Question 3

What parts of an organism don’t decay easily?

Answer 3

Hard parts like teeth and bones

Question 4

How do animal remains turn into fossils?

Answer 4

By stopping or slowing down decay by being kept in certain conditions such as having no oxygen or microbes

Question 5

What are some other fossils?

Answer 5

~ Traces like footprints

~ Burrows

Question 6

What sort of creatures are more likely to decay quickest?

Answer 6

Soft bodied ones (eg slugs)

Question 7

Why is there no evidence of the creatures very early on?

Answer 7

~ They were mainly soft bodied so decayed away

~ Or their fossils have been lost due to geological activity (erosion, volcanic activity)

Question 8

What can fossils show?

Answer 8

~ How new organisms arise
~ How new species are formed
~ How some species may have become extinct

Question 9

Why is there uncertainty about the evolution of creatures over time?

Answer 9

Because of the lack of enough valid and reliable evidence

Question 10

What can cause extinction?

Answer 10

~ New competitors 
~ New disease 
~ New predators
~ Catastrophe
~ Environmental change

Question 11

What has impacted the numbers of the Dutch elm tree?

Answer 11

It was infected with Dutch elm tree disease

Question 12

What happened to the dodo bird?

Answer 12

~ Lived in Mauritius in 17th century

~ Humans hunted them and rats ate their eggs

Question 13

Why did the numbers of red squirrel decrease?

Answer 13

New competitors (grey squirrels) evolved and took lots of the red squirrels food

Question 14

How can catastrophes affect species?

Answer 14

They can destroy habitats and kill those animals

Question 15

What is genetic variation caused by?

Answer 15

A range of alleles

Question 16

What does isolation mean for species?

Answer 16

They are separated by a barrier (mountains, sea, river, stream)

Question 17

How could the environment affect species?

Answer 17

~ Could be warmer
~ Could have different types of food
~ Could have different plants

Question 18

What is natural selection?

Answer 18

~ Variation sped up by mutation
~ Survival of fittest
~ Advantaged individuals breed
~ Genes passed on

Question 19

What is speciation?

Answer 19

When species become too different to interbreed

Question 20

What mainly affects speciation?

Answer 20

Environmental change

Question 21

What did Darwin find when he was in the Galapagos Islands?

Answer 21

~ He found finches on the different islands

~ They all had different adaptations, particularly their beak shape, to help them eat the food on their island

Question 22

What can nerve cells be used to treat?

Answer 22

Parkinson’s disease

Question 23

What are some different types of stem cells?

Answer 23

~ Embryonic stem cells
~ Foetal stem cells
~ Adult stem cells

Question 24

What can genetic engineering be used for?

Answer 24

~ Hormone and medicine production

~ Genetically modified crops

Question 25

How are hormones and medicine produced from genetic engineering?

Answer 25

~ Genes are cut out using enzymes ~ Genes are transferred from one organism to another ~ These organisms are used

Question 26

How are genetically modified crops produced from genetic engineering?

Answer 26

~ Genes are transferred to another organism at the early stage of development ~ The organism develops desired characteristics

Question 27

Why can stem cells be used to treat disorders?

Answer 27

Because they are unspecialised

Question 28

How many parents does asexual reproduction require?

Answer 28

1

Question 29

How many parents does sexual reproduction require?

Answer 29

2

Question 30

What does asexual reproduction produce?

Answer 30

Identical individuals (clones) of the parent

Question 31

What does sexual reproduction require?

Answer 31

~ Mixing of genes | ~ Fertilisation of gametes

Question 32

What happens with the modern cloning technique of tissue culture?

Answer 32

~ Cells taken from leaf/stem/roots ~ Cells encouraged to grow by being put in agar jelly ~ Cells then grow into plants which are then placed in soil

Question 33

What happens with the modern cloning technique of embryo transplants?

Answer 33

~ An embryo is split into balls of smaller cells | ~ One of these small balls of cells are put in the womb of host mothers

Question 34

What happens with the modern cloning technique of adult cell cloning?

Answer 34

``` ~ Skin cell taken from animal 1 ~ Egg cell taken from animal 2 ~ Nucleus from skin cell is placed in egg cell ~ Electric shock is given to cell ~ Placed in a host mother ```

Question 35

What is a genetically modified crop?

Answer 35

A crop that has had its genes modified by having genes from another organism added to it to adapt its characteristics

Question 36

What are some examples of genetically modified crops?

Answer 36

~ Cotton crops ~ Tomato crops ~ Corn crops ~ Maize crops

Question 37

What are some advantages of genetically modified crops?

Answer 37

~ Improves strength of crops ~ Improves growth ~ Effective for several years

Question 38

What are some disadvantages of genetically modified crops?

Answer 38

~ Damage to the environment ~ Potential damage to humans ~ More expensive in some cases ~ Can reduce the number of species

Question 39

What is a species?

Answer 39

A group of organisms capable of interbreeding and producing fertile offspring

Question 40

What is Darwins theory of evolution by natural selection?

Answer 40

All species of living things have evolved from simple life forms that first developed more than 3 billion years ago

Question 41

What was Lamarcks theory?

Answer 41

~ That a change in environment over time led to more use of neck and legs ~ Led to increased size of characteristic acquired dying lifetime ~ This characteristic was passed to offspring

Question 42

Why may 2 species have evolved from 1 original species?

Answer 42

~ The species became isolated ~ This change of environment caused genetic variation ~ Natural selection ~ Over time new species evolved which were too different to interbreed

Question 43

Where does evidence for early life forms come from?

Answer 43

Fossils