Topic 4

Question 1

Classification in Ecology

Answer 1

Species: A group of organisms that can interbreed and produce fertile, viable offspring.

Population: Group of organisms of the same species, living in the same area at the same time.

Community: A group of different populations living together and interacting in a given area.

Habitat: The environment in which a species lives or the normal location of an organism.

Ecosystem: A community and also its environment (all biotic and abiotic factors).

Question 2

Debates in Climate Change

Answer 2

Is current climate change natural?
Claim: Historical data show temperature cycles.
Counter: Past changes were not as abrupt. Ocean levels are rising, pH decreasing.

Are greenhouse gases the cause?
Claim: Changes could be caused by sunspots.
Counter: Climate changes don’t match sun activity CO2 levels are highest ever recorded.

Are climate models reliable?
Claim: Models may make varying predictions.
Counter: All the climate models are predicting a temperature increase by 2100.

Question 3

Aerobic and Anaerobic conditions in relation to fossil fuels

Answer 3

In aerobic conditions, saprotrophic bacteria will break down
organic material and return it to the soil, this is otherwise known as decomposition.

In anaerobic conditions, decomposition is prevented as the
saprotrophic bacteria can’t function effectively. Anaerobic respiration will produce organic acids because of the low ph.

Question 4

Hypothesis in Chi- Squared Test

Answer 4

Null Hypothesis – There is no association, so distribution is random.

Alternative Hypothesis – There is an association, and this association can be positive or negative.

Question 5

Trophic Levels

Answer 5

1. Producer
2. Primary Consumer
3. Secondary Consumer
4. Tertiary Consumer

Question 6

Green House Effect

Answer 6

The greenhouse effect is a process that increases average temperatures. This process goes as follows:
Radiation incomes from the sun including short-wave ultraviolet (UV) radiation.This radiation may also be emitted by the Earth as long-wave infrared (IR) radiation.Greenhouse gases absorb and re-emit this infrared radiation as heat. Greenhouse gases include: Carbon dioxide, water vapor, methane & nitrogen oxides.

Question 7

Combustion

Answer 7

Hydrocarbons undergo combustion in the presence of O2. The reaction is exergonic and CO2 and H2O is produced from the reaction. The energy produced by combustion reactions is usually
used to power industrial processes. The combustion of fossil fuels is the reason for a
significant increase in atmospheric CO2 concentrations otherwise known as global warming.

Question 8

Pyramids of Energy

Answer 8

Pyramids of energy are representations of the amount of
energy available at each trophic level.

Question 9

Organic Conversions

Answer 9

Autotrophs convert carbon dioxide from the atmosphere into organic
compounds through the process of photosynthesis. Equation for photosynthesis: 6CO2 + 6H2O → C6H12O6 + 6O2

Heterotrophs obtain organic compounds through feeding.
The breakdown of organic compounds occurs through cell respiration ,in order to produce ATP, and releases carbon dioxide as a by-product. Equation for cellular Respiration: C6H12O6 + 6O2 → 6CO2 + 6H2O

Question 10

Chi-Squared Test

Answer 10

A chi-squared test can be applied to quadrat sampling data in order to determine if there
is a statistically significant association between distribution of two species.