Module 4

Question 1

Define Biosphere

Answer 1

The biosphere is the worldwide sum of all ecosystems

Question 2

Define Ecosystem

Answer 2

An ecosystem is a community of living organisms in conjunction with the non-living components of their environment, interacting as a system

Question 3

Define Biome

Answer 3

A biome is a major life zone characterised by vegetation type (terrestrial) or physical environment (aquatic)

Question 4

What are the four major physical components of climate?

Answer 4

Temperature, precipitation, sunlight, and wind.

Question 5

Describe how variation in solar radiation affects the global climates

Answer 5

The warming effect of the sun establishes temperature variations, circulation of air and water, and evaporation of water. This causes latitudinal variations in climate.

Question 6

What are the main aquatic biomes of the world?

Answer 6

Marine and freshwater biomes.

Question 7

What are the characteristics of marine biomes?

Answer 7

They have an average salt concentration of 3%
Oceans make up the largest marine biome, covering about 75% of the Earth’s surface.

Question 8

What is the zonation in aquatic biomes?

Answer 8

Photic zone, aphotic zone, pelagic zone, and abyssal zone.

Question 9

What is a thermocline?

Answer 9

A temperature boundary that separates the warm upper layer from the cold deeper water.

Question 10

What is an oligotrophic lake?

Answer 10

A lake that is nutrient-poor and generally oxygen-rich

Question 11

What is a eutrophic lake?

Answer 11

A lake that is nutrient-rich and often depleted of oxygen on deep zones or throughout if ice covered in winter

Question 12

Why does the Earth vary in solar radiation across latitudes?

Answer 12

The variation in solar radiation across latitudes is primarily due to the Earth’s spherical shape and its axial tilt relative to the Sun. Several factors contribute to this variation:

Angle of Incidence:
Sunlight is most intense near the equator and less intense towards the poles because of the angle at which it strikes the Earth’s surface.
Path Length:
Sunlight travels a shorter path through the atmosphere near the equator, maintaining higher intensity, while it travels a longer path towards the poles, reducing intensity.
Duration of Insolation:
Near the equator, daylight hours are consistent, leading to a steady influx of solar radiation, whereas towards the poles, daylight hours vary greatly with the seasons, causing fluctuations in solar radiation.
Seasonal Changes:
Earth’s axial tilt causes seasonal variations, resulting in higher solar radiation in the hemisphere tilted towards the Sun during summer and lower radiation in the hemisphere tilted away during winter.

Question 13

What is an autotroph?

Answer 13

Autotrophs - are self feeders that sustain themselves without eating anything derived from other organisms.

Question 14

What are heterotrophs?

Answer 14

Heterotrophs - obtain organic material from other organisms. Heterotrophs are the consumers of the biosphere, some eat other living organisms, while others, called decomposers, consume dead organic material or faeces.

Question 15

What is photosynthesis?

Answer 15

Photosynthesis is the process that occurs within chloroplasts that convert solar energy into chemical energy that is stored as sugar and other organic molecules.

Question 16

What is the first law of thermodynamics?

Answer 16

• energy can be transferred and transformed, but it cannot be created of destroyed.
• this can also be called the principle of conservation of energy

Question 17

What is the second law of thermodynamics?

Answer 17

• every energy transfer or transformation increases the entropy of the universe
• entropy is a measure of molecular disorder, or randomness.

Question 18

What is a trophic structure?

Answer 18

It is the feeding relationships between organisms within a community

Question 19

What is a food web?

Answer 19

a map that show who eats whom in an ecosystem. It shows all the different connections between animals and plants.

Question 20

What are the major factors that control primary production in ecosystems?

Answer 20

Sunlight - main source of energy for photosynthesis, which is how plants make food.
Nutrients- like nitrogen, phosphorus, and potassium. Plants need these to grow.
Water- essential for photosynthesis and plant growth.
Temperature - affects the rate of photosynthesis. Most plants have a preferred temperature range of growth.
Carbon dioxide (CO2) - plants use it to make food during photosynthesis.
Soil quality - affects how well plants can grow. Good soil with the right nutrients helps plants thrive

These factors together determine how much food (or biomass) plants can produce through photosynthesis, which is the primary production in ecosystems.

Question 21

What is the rate of decomposition controlled by?

Answer 21

temperature, moisture, and nutrient availability.

Question 22

What is a detritivore?

Answer 22

An organism that feeds on and breaks down dead plant or animal matter in the process of chemical cycling

Question 23

What is a biogeochemical cycle?

Answer 23

the movement of nutrients and other elements between biotic and abiotic factors

Question 24

What is Evapotranspiration?

Answer 24

Evapotranspiration is the combined process of water evaporation from the land and transpiration from plants. It involves the release of water vapor into the atmosphere through both plant leaves and soil surfaces.

Question 25

What is the water cycle?

Answer 25

Movement of water through evaporation, transpiration, condensation, precipitation, and surface/groundwater flow

Question 26

What is the carbon cycle?

Answer 26

Process where carbon moves between the atmosphere, organisms, and the Earth’s crust

Question 27

What is the nitrogen cycle?

Answer 27

Conversion of nitrogen between different chemical forms essential for amino acids, proteins, and nucleic acids

Question 28

What is the phosphorus cycle?

Answer 28

Movement of phosphorus through rocks, soil, water, and organisms in ecosystems

Question 29

Which terrestrial biome has the lowest variation in annual mean temperature?

Answer 29

Tropical forest

Question 30

When thinking about the law of conservation of mass, what is a likely consequence for an ecosystem where the primary producers in that ecosystem are being harvested at an unsustainable rate?

Answer 30

Reduced amount of food available for trophic level 2 consumers

Question 31

Which environment is most likely to have the highest rates of decomposition?

Answer 31

Low latitude rainforest (warm, aerobic, wet)

Question 32

Two lakes are within 50 km of one another, are both surrounded by open wetlands and grasslands, but are in different local rainfall catchments.
One lake is eutrophic and the other is oligotrophic.
What factor is most likely to be different between these two lakes with respect to their differences in primary productivity?

Answer 32

Average annual nutrient influx

Question 33

What feature of aquatic biomes is characteristic of only estuaries?

Answer 33

Freshwater and saltwater mix

Question 34

What causes seasons on Earth?

Answer 34

The constant tilt of the Earth, combined with its orbit around the sun

Question 35

Deep oceanic waters support fewer organisms than shallower oceanic waters.
What is the principle limiting factor in deeper waters causing this?

Answer 35

Light

Question 36

Describe the role of a detritivore in a terrestrial ecosystem

Answer 36

Reintroduces organic and inorganic nutrients back into soil

Question 37

Rising air cools and loses water as precipitation.
Which environmental situation(s) would this phenomenon contribute to?

Answer 37

1. Deserts on the leeward side of mountains
2. Higher rainfall in winter than summer in temperate coastal areas
3. Low rainfall in coastal zones

Question 38

In lakes, a thermocline can form as surface waters warm.
What can result from this?

Answer 38

1. Limited mixing of surface waters and colder, deeper waters
2. Nutrient transfer from deeper waters is limited
3. Oxygen levels can be limited in deeper waters

Question 39

Plants with reduced leaf area and deep root systems would be likely to be found in which terrestrial biomes?

Answer 39

Deserts and Temperate grassland.

This is because in these biomes, plants with reduced leaf area and deep root systems are often adapted to environments where water availability is limited. These adaptations help the plants minimize water loss through transpiration and access water from deeper soil layers.

Question 40

How does phosphorus transfer from minerals in rocks into living tissue?

Answer 40

Through erosion of sediment, followed by nutrient uptake

Question 41

Which of the following is a chemical element that is stored underground as coal, released as CO2 by the burning of fossil fuels, and is a basic component of the sugars that plants make during photosynthesis?

Answer 41

Carbon