5 Greenhouse effect

Question 1

what is happening at 1?

Answer 1

1 sun produces radiation at different wavelengths

1 shorter wavelengths pass through the atmoshpehere

Question 2

what is happening at 2?

Answer 2

some energy at the wrong wavelength gets reflected back out (LONG)

Question 3

what is happening at 3?

Answer 3

energy is absorbed by the land, heating it and its surroundings up

Question 4

what is happening at 4?

Answer 4

greenhouse gases will absorb the heat and re-emit the heat energy, some to earth other to space (above ozone layer)

Question 5

what is happening at 5?

Answer 5

heat is effectively trapped and warms the earth (important for life to occur and all metabolic reactions)

Question 6

name two greenhouse gases.

Answer 6

CO₂ and methane

Question 7

is the greenhouse effect good?

Answer 7

YES! the earth needs to be at a temperature where water is not frozen as it is needed for all life

Question 8

evaluate the use of temperature records as evidence for climate change.

Answer 8

• reliable but short term
• only more accurate in recent decades
• remember to look at error bars

Question 9

how is dendrochronology used as evidence for cc?

Answer 9

• scientist remove core from trees and date each ring by counting the total number
  
  • by looking at the thickness of each ring they can see what the climate was like each year

Question 10

ring are thicker when the climate at the time was ________. why?

Answer 10

WARMER= thicker

better conditions for growth

Question 11

what is a climate proxy?

Answer 11

-preserved physical characteristics of the past that stand in for direct estimations

Question 12

what is a peat bog?

Answer 12

areas of wetland that have formed layers over thousands of years due to dead plant material mainly

Question 13

how is pollen in part bogs evidence for cc?

Answer 13

• scientists can take cores from peat bogs and extract pollen grains from different layers
• then identify the plant species the pollen came from
• pollen from similar plant species now can represent the climate conditions needed for this plant to successfully grow= approx temp of climate

Question 14

what does a gradual increase in pollen from a plant species that is more successful in warmer climates show?

Answer 14

-increase in global temperature

Question 15

explain why only pollen from successful plant species is preserved in peat bogs

Answer 15

only fully grown/mature species produce pollen

Question 16

explain how biofuels may reduce global warming.(3)

Answer 16

• possibly carbon neutral/ to replace fossil fuels
• plants used for biofuels
• CO₂ used for photosynthesis by plants

Question 17

what is a carbon sink?

Answer 17

any reservoir natural or otherwise that stores some carbon containing chemical compound= therefore lowing the conc of CO2 in the atmosphere (vegetation+ the ocean)

Question 18

what are the two main causes of climate change?

Answer 18

greenhouse gases - CO₂ and methane

Question 19

key points of natural selection. four marker

Answer 19

• mutation which causes variation
• selection pressures/ environmental stress
• one allele become more advantageous
• survival of the fittest those with this allele survive, the rest die out
• reproduce and pass down allele= allele frequency changes

Question 20

what is allopatric speciation?

Answer 20

due to 2 different areas so geographical isolation, eg a river

Question 21

what is sympatric speciation?

Answer 21

speciation WITHOUT geographical isolation, takes place in the same area

-eg due to a mutation

Question 22

Speciation happens when ______ of the _____ species become ___________ isolated, ________ gene flow between two populations. This mean natural selection act on each population _________.

Answer 22

• populations
• same
• reproductively
• reducing
• separately

Question 23

define gene pool.

Answer 23

collection of genes in the population

Question 24

define species.

Answer 24

organisms that can reproduce to give fertile offspring

Question 25

define speciation.

Answer 25

evolution of a new species from existing ones

Question 26

what process removes CO2 from the atmosphere?

Answer 26

photosynthesis

Question 27

what 2 processes add CO2 to the atmosphere?

Answer 27

respiration and combustion

Question 28

Explain why the 'anaerobic oxidation of methane' could be a 'key climate regulator'.3

Answer 28

- methane is a greenhouse gas - greenhouse gases trap/absorb heat energy - less methane in atmosphere= less climate change

Question 29

what four fuels, could be considered to be biofuels. **(1)** **A** biodiesel, ethanol, hydrogen, methane **B** biodiesel, ethanol, hydrogen, propane **C** biodiesel, ethanol, methane, propane **D** biodiesel, hydrogen, methane, propane

Answer 29

**A** biodiesel, ethanol, hydrogen, methane

Question 30

Large areas of land may need to be cleared in order to produce biofuels. This might involve deforestation. Discuss why the production of biofuels may not be carbon neutral.**(5)**

Answer 30

- carbon neutral meaning - forests are carbon sinks - deforestation = less plants= less CO₂ removed via photosynthesis - burning of trees/biofuels produces CO₂

Question 31

Explain how the combustion products, from the burning of fuels, may lead to global warming.**(4)**

Answer 31

- CO₂ produced which is a greenhouse gas - gases build up/remain in upper atmosphere - absorb/trap heat energy/IR - reflected form earths surface - mean temp of earth's surface/atmosphere increases

Question 32

Suggest why using first generation biofuels instead of petrol and diesel could reduce global warming.(3)

Answer 32

- using/burning fossil fuels releases CO₂ - CO₂ is a greenhouse gas - carbon dioxide taken in by plants via photosynthesis during production of plants for biofuel production

Question 33

Second generation biofuels are now being developed. These will use non-food parts of crops that contain the polymers cellulose and lignin. Bacteria can be used to synthesise ethanol from these polymers. However, enzyme treatment is necessary before the bacteria can use these polymers. (i) Name a part of a plant stem that would contain these polymers.

Answer 33

xylem

Question 34

Explain how studying pollen grains in peat bogs can provide evidence of climate change.**(4)**

Answer 34

- pollen is preserved in peat bogs - a plant species can be identified from its pollen - climate affects type of plant grown - depth=period of time since pollen was produced - change in climate are indicated by changes in climate

Question 35

The percentage of strains of Mycobacterium tuberculosis resistant to the antibiotic INH has increased during these three years. Suggest how natural selection could have resulted in this increase.(3)

Answer 35

- bacteria has mutation in its DNA/gene - presence/usage of INH antibiotic acts as a selection pressure - advantageous allele (for resistance) is passed on - bacteria divide asexually via mitosis - Increase in allele frequency

Question 36

DNA samples were collected from these two populations of elephants. Scientists have concluded that the forest elephant and the savannah elephant are two different species. \* (i) Analyse the data and the information provided to comment on the validity of this conclusion.**(6)**

Answer 36

- feeding behaviours - anatomy - genetic differences - no info on reproducing to give fertile offspring - no info on number of elephants used for DNA analysis

Question 37

Explain how two species of African elephant could evolve from a common ancestor.(3)

Answer 37

- two populations are geographically isolated - reduced gene flow between two populations - leads to allopatric speciation - different selection pressures lead to natural selection

Question 38

Name one process that would have validated Pettersson's paper before it was published in the journal known as the Proceedings of the National Academy of Science (paragraph 58).**(1)**

Answer 38

peer review

Question 39

(a) Place a cross in the box next to the best definition of a species. **A** individuals can interbreed to produce fertile offspring **B** individuals can interbreed to produce hybrid offspring **C** individuals can interbreed to produce sterile offspring **D** individuals can interbreed to produce offspring

Answer 39

**A** individuals can interbreed to produce fertile offspring

Question 40

A new species of mosquito has evolved in the tunnels of the London Underground. These mosquitoes are believed to be the descendants of bird-biting mosquitoes which colonised the tunnels 100 hundred years ago. The mosquitoes now feed on rats, mice and human beings instead of birds. Explain how this species of mosquito may have evolved.(5)

Answer 40

- geographically isolated in the tunnel - RANDOM genetic mutations allow some to feed on things above - these individuals are more likely to survive and reproduce - this allele is passed down to offspring , proportion with this mutation will increase over time - genetically distinct + define species

Question 41

Suggest why successful interbreeding between chiffchaffs and willow warblers (2 diff species) would make some scientists doubt their classification as separate species.(3)

Answer 41

- offspring produced - same species means they can produce fertile offspring - offspring of different species may be infertile due to genetic incompatibility/ diff number of chromosomes

Question 42

Suggest reasons why the two species of birds do not interbreed.(3)

Answer 42

- reproductively isolated - different breeding times - anatomically isolated

Question 43

Records show that very little change in the appearance of chiffchaffs and willow warblers has occurred during the last two hundred years. Suggest why the rate of change in the appearance of these two species is relatively slow.**(3)**

Answer 43

- both well-adapted - no recent mutations to improve survival - little changes to allele frequency and gene flow - little change in environment

Question 44

define allele frequency.

Answer 44

the proportion of one allele within a population