Changes to populations and the environment

Question 1

What is succession?

Answer 1

A directional change in a community over time.

Question 2

What is meant by primary succession?

Answer 2

Where an area previously devoid of life is colonized by pioneer species.

Question 3

What is a pioneer species?

Answer 3

Species that can survive in hostile environments and colonies bare rock or sand. Ex. lichen.

Question 4

Summarize the process of succession

Answer 4

Pioneer species colonies the area. They die, decompose and add nutrients to the ground. Over time, this allows more complex organisms to survive.

Question 5

What are seres?

Answer 5

Various intermediate stages in succession in an ecosystem progressing towards a climax community.

Question 6

Define secondary succesion

Answer 6

A type of succession in which a habitat is re-colonised after a disturbance.

Question 7

What is the climax community and how is it reached?

Answer 7

The final stage of succession, where the ecosystem is balanced and stable. It’s reached when the soil is rich enough to support large trees or shrubs and the environment is no longer changing.

Question 8

How does succession affect species diversity and the stability of a community?

Answer 8

It increases it.

Question 9

Describe four pieces of evidence for climate change.

Answer 9

-Increasing levels of CO2, a greenhouse gas
-Changing patterns in t° records
-Analysis of pollen grains from peat bogs indicates which plant species were present when the peat formed
-Dendrochronology

Question 10

What is dendrochronology?

Answer 10

Measurement of tree ring width to analyze the temperature and moisture of the year in which the ring was added.

Question 11

What is anthropogenic climate change?

Answer 11

Climate change caused by human activity like deforestation, burning of fossil fuels, intensive agriculture.

Question 12

What is the greenhouse effect?

Answer 12

Greenhouse gases CO2 and methane absorb infrared radiation from the sun. Warms the earth’s surface and atmosphere.

Question 13

Suggest two controversial scientific debates surrounding climate change

Answer 13

What should be done to reduce climate change? To what extent are human actions responsible for climate change?

Question 14

Why might scientific conclusions on controversial issues differ?

Answer 14

They may require suggestions rather than empirical fact, and it depends on the intention of the researcher (subconscious bias or pressure from an institution)

Question 15

How can knowledge of the carbon cycle be used to reduce atmospheric carbon dioxide levels?

Answer 15

Increase photosynthetic absorption of CO2=reforestation
Reduce CO2 release= burn fewer fossil fuels

Question 16

How can models of future climate change be generated?

Answer 16

By extrapolating data

Question 17

Why do climate change models have limitations?

Answer 17

Models assume the pattern continues and don’t consider factors that may change later, like reduction in greenhouse gas emissions.

Question 18

State two geological effects of climate change

Answer 18

Rainfall patterns change, seasonal cycles change

Question 19

How can climate change affect plants and animals?

Answer 19

Distribution of species and migratory patterns change. This increases interspecific competition. Selection pressures change and disruption to life cycles and development (e.g. sex in reptiles)

Question 20

Explain how increasing t° above the optimum affects the rate of an enzyme-controlled reaction

Answer 20

Increased vibrations break hydrogen and ionic bonds in tertiary structure, active site changes shape, enzyme is denatured, no more enzyme-substrate complexes can form and the rate of reaction decreases.

Question 21

What is Q10?

Answer 21

Temperature coefficient. Measures the rate of change of a reaction when the t° is increased by 10 °C.

Question 22

How can increased t° due to climate change affect organisms on a molecular scale?

Answer 22

Organisms typically have proteins adapted to work optimally in their natural climate. If the t° increases, the proteins may denature and will be unable to function correctly.

Question 23

What is evolution?

Answer 23

Change in allele frequency in gene pool of a population. Results in development of new dominant characteristics.

Question 24

What is natural selection?

Answer 24

The process by which organisms that are better adapted to their environment are able to survive and reproduce. This contributes to evolution over time.

Question 25

How does natural selection lead to evolution?

Answer 25

Random mutations result in new alleles. Some of these provide an advantage, making the individual more likely to survive and reproduce. Offspring receive the allele and frequency increases over many generations.

Question 26

Why does natural selection occur?

Answer 26

Predation, competition, disease.

Question 27

What is speciation?

Answer 27

The formation of a new species due to the evolution of two reproductively separated populations.

Question 28

What are the two different types of speciation?

Answer 28

Allopatric speciation and sympatric speciation.

Question 29

What is meant by sympatric speciation?

Answer 29

Speciation resulting from a non physical barrier, like a mutation that no longer allows two organisms to produce fertile offspring, changes in anatomy or behavior.

Question 30

What is reforestation?

Answer 30

The replanting of trees to replenish forests that have been destroyed.

Question 31

What are biofuels?

Answer 31

Fuels which have been made from biomass (plant and animal matter). They can be a carbon-neutral and renewable alternative to fossil fuels.

Question 32

What is sustainability?

Answer 32

The ability to maintain a process or supply over time. Supplying the present generation without depriving the future generations of the resource.