Biodiversity, Deforestation + Effects

Question 1

biodiversity definition

Answer 1

the measure of how many different species live in an ecosystem

Question 2

how do you measure biodiversity using quadrats?

Answer 2

• use quadrats and random sampling
• for each quadrat, use an identification key and record the number of each different species

Question 3

how do you find out the effect of abiotic or biotic variables on biodiversity?

Answer 3

• select at least two areas where the variable is different
• measure/describe the variable in each area
• estimate the biodiversity in each area

Question 4

why have large areas been cleared in recent years?

Answer 4

there has been an increase in human population and development in industrial machinery

Question 5

how many rainforests have been cleared over the last 75 years?

Answer 5

over half

Question 6

how many hectares of rainforest ae destroyed each day?

Answer 6

32,000

Question 7

what happens because of deforestation?

Answer 7

• the habitats of the organisms that live there
• it causes extinctions and dramatically reduces biodiversity
• fall trees may also be burned as a source of energy which releases carbon dioxide

Question 8

how many species of plant, animal and insect are lost each day because of deforestation?

Answer 8

several hundreds

Question 9

does deforestation increase or reduce biodiversity?

Answer 9

reduce

Question 10

how does the carbopn cycle affect global warming?

Answer 10

• during photosynthesis carbon dioxide is taken into plants, and becomes part of the carbohydrates and other biological molecules
• the plant becomes a ‘carbon sink’
• if deforestation occurs, there are less plants to store carbon, and carbon dioxide levels in the atmosphere will increase
• oxygen levels will decrease, as there is less photosynthesis

Question 11

how does burning trees release carbon dioxide into the atmosphere?

Answer 11

the combustion causes carbon dioxide release, which causes a further increase in atmospheric carbon dioxide

Question 12

how does deforetation cause leaching?

Answer 12

• in a normal forest, water is absorbed by the soil and then taken up by the roots of plants
• if deforestation occurs then the water is no longer taken up by the plants, and begins to run off from the soil into rivers or lakes
• mineral ions that occur in the soil are dissolved into the water - if then absorbed by plants this can be transferred to them for growth
• if deforestation occurs, this water will run into nearby rivers or lakes, which could lead to mineral ions being removed from the soil and eutrophication

Question 13

how does deforestation lead to soil erosion?

Answer 13

• the water running off from deforested areas may carry away some of the topsoil, causing erosion
• because there is no plants in the area due to deforestation, there are no roots holding the soil in place
• the topsoil contains the most fertile, mineral ion rich materials, which if lost makes plants have difficulty growing

Question 14

how does deforestation lead to evapotranspiration?

Answer 14

• this is the process by which water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from plants
• this evaporated water moves into the atmosphere and eventually makes rain in rain clouds
• when the rain clouds rain onto plants the cycle continues - but deforestation breaks this cycle
• this can lead to droughts