Topic 4. Ecology

Question 1

What are species?

Answer 1

Organisms that can interbreed and produce fertile offspring.
Organisms from different species that can breed cross-breed, which does not create fertile offspring.

Question 2

What is a population?

Answer 2

A group of organisms of the same species living in the same area at the same time. 2 populations of the same species living in different areas are still the same species since they can interbreed. However these populations may start to evolve differently.

Question 3

What is a community?

Answer 3

A community is multiple populations living in the same area and interacting with eachother.

Question 4

What is an ecosystem?

Answer 4

An ecosystem is a community and its abiotic environment. Organisms depend on the abiotic environment. Ecologists study both individual components and interactions in an ecosystem.

Question 5

What are autotrophs?

Answer 5

Autotrophs are species that gain nutrition from the abiotic environment. Either via photosynthesis or via chemosynthesis.

Question 6

What are heterothrops?

Answer 6

Heterotrophs are species that gain nutrition from other organisms

Question 7

What are consumers?

Answer 7

Consumers are heterotrophs that gain nutrition through ingestion of other living organisms. Either herbivores, omnivores or carnivores.

Question 8

What are herbivores?

Answer 8

Species that gain nutrition by ingesting plants. For example guinepigs and cows.

Question 9

What are omnivores?

Answer 9

Omnivores are consumers that gain nutrition by ingesting plants and animal matter. For example humans and bears.

Question 10

What are carnivores?

Answer 10

Carnivores are consumers that gain nutrition by ingesting animal matter. For example wolves and lions.

Question 11

What are scavengers?

Answer 11

Scavengers are heterotrophs that gain nutrition by ingesting dead and decaying carcasses. For example hyenas and vultures.

Question 12

What are saprotrophs?

Answer 12

Saprotrophs are heterotrophs that obtain nutrients from external digestion of dead organisms. For example bacteria and fungi.

Question 13

What are detritovores?

Answer 13

Detritovores are heterotrophs that gain nutrition by internal digestion of detritus. For example snails and earthworms.

Question 14

How is the supply of inorganic nutrients maintained?

Answer 14

The supply of inorganic nutrients are maintained by nutrient cycling. They can be endlessly recycled.

Question 15

How does nutrient cycling work?

Answer 15

Autotrophs obtain inorganic nutrients from the abiotic environment, they are then ingested by heterotrophs. Heterotrophs release inorganic nutrients as a byproduct. Sprothrophs decompose the ramains of dead orgainsms into the soil. The inorganic nutrients can then be used by autotrophs again and the cycle continues.

Question 16

What is the energy source for most autotrophs?

Answer 16

The energy source for most autotrophs is sunlight. The use sunlight to carry out photosynthesis, which transforms light energy into chemical energy. The chemial energy is storedin organic compounds such as sugar.

Question 17

What is the process of photosynthesis?

Answer 17

Photosynthesis is the reverse reaction of cell respiration.
6CO₂+ 6H₂O + light energy → C₆H₁₂O₆ + 6O₂

Question 18

What are the energy source for heterotrophs?

Answer 18

The energy source for heterotrophs depend on where in a food chain the fall. Primary consumers energy source is autotrophs, where as secondary or tertiary consumers energy source is other heterotrophs. All heterotrophs heterotrophs break down the organic molecules in which chemical energy is stored in order to derive theie energy. This is done via cell respiration, which produces ATP that fuelss metabolic processes.

Question 19

What is the process of cell respiration?

Answer 19

Cell respiration is the reverse reaction of photosynthesis.
C₆H₁₂O₆ + 6O₂ →6CO₂+ 6H₂O + ATP (chemical energy)

Question 20

What are food chains?

Answer 20

Food chains are used to show how different organisms feed and gain nutrition. The first organism in a food chain is called a produce, the second one is a primary consumer, the third one is secondary consumer, and the fourth one is a tertiary consumer. The position an organism has in a food chain is refered to as a trophic level.

Question 21

How is energy in organisms lost?

Answer 21

During cell respiration the organic molecules storing energy are oxidised. Oxidation is a exothermic reaction which means that energy is realeased. Most of the energy released is used to form ATP, but some of the energy is converted into thermal energy (heat). Some energy is also released through the organisms feces

Question 22

What is thermal energy and what do organisms do with it?

Answer 22

Thermal energy, or heat, is produced when exothermic reactions occur in an organism. These exothermic reactions are when a hetertroph converts the chemical energy that they have ingested. Thermal energy can not be converted to anothr type of energy by living organisms, so it is released from the organism and gets lost from the ecosystem.

Question 23

What do pyramids of energy illustrate?

Answer 23

Pyramids of energy illustrates the loss of energy between different trophic levels. An organisms only gains about 10% of the energy of the organism that it is feeding on, so about 90% of the energy is lost. This means that biomass also is lost between different trophic levels. Since so much energy is lost higher leveled consumers need to eat more, in order to gain enough energy. If more energy is lost hunting than gained eating the trophic level becomes unviable.

Question 24

What is biomass?

Answer 24

Biomass is the total mass of a group of organisms, consisting of the cells and tissues of those organisms.

Question 25

What is the carbon cycle?

Answer 25

The carbon cycle is a biogeochemical cycle whereby carbon is exchanged between the different spheres ofthe earth.

Question 26

What are the spheres of earth?

Answer 26

• Atmosphere (air)
• Lithosphere (ground)
• Hydrosphere (water)
• Biosphere (living things)

Question 27

What do autotrophs do with carbon dioxide?

Answer 27

Autotrophs convert carbon dioxide into carbohydrates, lipids and other useful carbon compounds.

Question 28

What is carbon dioxide?

Answer 28

Carbon dioxide is the most abundant gas form of carbon. It is one of the greenhouse gases, and make up about 0.04% of the atmosphere. It is a byproduct of cell respiration, and it diffuses out of cells into the atmospere or the hydrosphere.

Question 29

How does carbon dioxide behave in water?

Answer 29

Carbondioxide can either exist as dissolved gas in water, or it combines with the water to fort carbonic acid. The carbonic acid can for hydrogen ions and hydrogen carbonate ions. The hydrogen ions lowers the pH of the water. Dissolved carbon dioxide and carbonic acid can be absorbed by aquatic plants that can turn them into useful carbon compounds.

Question 30

How is methane formed?

Answer 30

Methane is formed in anaerobic conditions, such as swamps or in the stomachs of cows. There methnogenic archaeans convert organic matter into methane. Some methane diffuses into the atmosphere while some accumulates under ground.

Question 31

What happens to methane in the atmosphere?

Answer 31

Methane can stay in the atmosphere for about 12 years. But after that it is oxidized to carbon dioxide and water.

Question 32

How is peat formed?

Answer 32

Peat is formed in waterlogged soils under anaerobic conditions. Saprothrops usually decmpose dead organic matter, but in waterlogged soils they can not get oxygen. So the partially decomposed matter will be compressed underground and form peat.

Question 33

How is coal formed?

Answer 33

Coal is formed when peat is buried far down under other sediments. The peat is then compressed and heated which results in a product of coal.

Question 34

How is oil and natural gas formed?

Answer 34

Oil and natural gas are formed under anaerobic conditions in mud at the bottom of oceans. Chemical changes occur when partially decomposed matter is compressed and heated, which produces oil and natural gas.

Question 35

What is combustion?

Answer 35

Combustion is the oxidation reactions that occur when a substance burns. Combustion of biomass and fossilized organic matter produces carbon dioxide and water. Combustionof fossil fuels ofter occur in cars and factories.

Question 36

How is limestone formed?

Answer 36

When organisms with calcium carbonate shells dies their shells will acumulate at the bottom of the ocean. They will be covered by non-porous sedimentary rock layer, which will result in the schells being compressed and heated. Which results in the shells turning into limestone.

This process is called sedimentation.

Question 37

What are greenhouse gases and what do they do?

Answer 37

Greenhouse gases are gases which trap heat within the atmosphere. They retain the heat by absorbing and emiting long-wave radiation.

The most abundant greenhouse gases are carbon dioxide and water vapour. Other common greenhouse gases are methane and nitrogen oxides.

Question 38

How is the impact of a greenhouse gas determined?

Answer 38

The impact of a greenhouse gas is determined by a combination of 2 factors:
* The ability to absorb long-wave radiation
* Concentration of the gas within the atmosphere. The concentration is determined bu its rate of release and its persistance.

Question 39

What is the greenhouse effect?

Answer 39

The greenhouse effect is a natural process that ensures that the earth remains at a stable temperature. This is done by greenhouse gases. Short-wave radiation is emited by the sun. when it reaches the earth it is converted to long-wave radiation (heat). Some long wave radiation is reflected back into space, but 85% is absorbed and re-emited back to earth.

Question 40

How does the concentration of a greenhouse gas relate to the average global temperature?

Answer 40

A correlation between carbon dioxide concentration and global temperature has been seen. This has been seen by analyzing the carbon dioxidelevels in air bubbels trapped in ice from thousands of years back. At times when the global temperature was higher the carbon dioxide concentration was higher. However it is not only the concentration of greenhouse gases that affect the global temperature.

Question 41

Why has there been an increase in the concentration of carbon dioxide?

Answer 41

The main cause for the increase in carbon dioxide is combustion. There has been a great increase in combustion of fossil fuels since the industrial revolution. Since the industrial revolution carbon dioxide levels have increased about 38%.

Question 42

What are the effects of climate change.

Answer 42

Due to the increased greenhouse effect the average global temperatur has increased, this is also known as global warming. This results in glaciers melting and thus raising the sea levels. It also causes a few spieces, such as polar bears, to die out.

An increase in temperatur also causes more water to evaporate from oceans, which results in greater and longer rain periods. An increase in the ocenas temperature can also result in more frequent and stronger tropical storms and hurricanes.

Question 43

What is ocean acidification?

Answer 43

Ocean acidification is when oceans pH-levels get lower due to hydrogen ions. There has been an increase in hydrogen ions du to an increase in carbon dioxide in oceans.

The hydrogen ions also bond to lone carbonate ions. Less carbonate ions results in thinner calcium carbonate shells for some mollusca. Aswell as corals dying since there isn’t enough carbonate for them to form their exoskeletons.