5.12

Question 1

List the evidence for climate change

Answer 1

1. Temperature/CO2 levels records
2. Pollen (trapped in sedimentary rock or peat bogs)
3. Dendrochronology

Question 2

Explain why pollen in peat bogs:
a) doesn’t decay
b) is useful for identifying species of plants

Answer 2

a) peat bogs are very waterlogged, acidic habitats so only anaerobic respiration can take place under the surface - preventing decomposition
b) pollen is specific to the species of plant it’s from so species can be found in an area by identifying its pollen

Question 3

Explain how pollen in peat bogs can be used to assess climate change over time

Answer 3

Pollen in peat bogs do little to no decaying, so the deepest pollen layers can be very old - providing information about what species was living nearby then, and therefore the likely climate conditions at the time (based on the species’ current needed climate). This can help show long term climate change.

Question 4

Explain why tree ring size differs from year to year

Answer 4

Each ring shows the new growth from year to year, a dryer and colder year will have a smaller ring than a hot and wet year.

Question 5

Explain how dendrochronology can be used to assess climate change over time

Answer 5

By measuring average climate by the size of tree rings, records of past climates can be estimated to compare to current climates - helping to show any long term climate change.