Biology || Ecosystems B9

Question 1

Individual?

Answer 1

A single organism.

Question 2

Population?

Answer 2

All organisms of the same species in a habitat.

Question 3

Community?

Answer 3

All organisms in a habitat (can be different species).

Question 4

Ecosystem?

Answer 4

Community of biotic organisms and all abiotic conditions too.

Question 5

Independence?

Answer 5

Organisms depend on each other for food, survival and reproduction.

Question 6

Mutualism?

Answer 6

Relationship between two organisms,

This benefits both the organisms,

E.g. bees and flowers.

Question 7

Parasites?

Answer 7

Parasite takes what it needs from another organism to survive but the host doesn’t benefit,

E.g. fleas on dogs.

Question 8

Abiotic Factors That Effect Communities?

Answer 8

Temperature,

Amount of water supply,

Light intensity,

Levels of pollutants.

Question 9

Biotic Factors That Affect Communities?

Answer 9

Competition,

Predation.

Question 10

Temperature Affecting Communities?

Answer 10

Organisms can sometimes only live in certain temperature.

Question 11

Amount Of Water Affecting Communities?

Answer 11

Certain plants can only live in souls that that damper,

E.g. daisies need damp soil.

Question 12

Light Intensity Affecting Communities?

Answer 12

E.g. grasses being replaced by fungi and trees grow and create shade.

Question 13

Level Of Pollutants Affecting Communities?

Answer 13

E.g. lichen are unable to survive is the concentration of sulphur dioxide is too high in the air.

Question 14

Competition Affecting Communities?

Answer 14

Organisms may compete with community or population to get the same resources,

E.g. red and grey squirrels live in the same habitat and eat the same food.

Question 15

Predation Affecting Communities?

Answer 15

E.g. If the number of predictors increases, the number of gazelles might decrease.

Question 16

Quadrant?

Answer 16

Square of frame put on a known area to compare how common an organism is in two sample areas.

Question 17

Working Out Mean?

Answer 17

Total Number Of Organisms
—————————————-
Number Of Quadrats

Question 18

How To Use A Quadrat?

Answer 18

Divide sample area into grid,

Use random number generator to pick coordinates,

Place a 1m2 quadrat on ground at random point within the first sample area,

Count all organisms in the quadrat,

Repeat this,

Work out mean of organisms in the quadrats,

Repeat steps in the second sample area,

Compare the two means,

P. 68 in book.

Question 19

Estimating Population Size?

Answer 19

You have to find the mean of organisms in 1m2,

Do Mean Number Of Organisms Per M2

X (Multiply)

The Total Area Of The Habitat (m2).

Question 20

Belt Transects?

Answer 20

This is used to measure how organisms can change across a habitat or how organisms are distributed throughout a habitat,

Measure the species and then look at the abiotic factors and see how this effects the organisms,

E.g. if a species is more or less common across a gradient,

Quadrats are laid in a long line to make a belt transect,

Mark the line of the area you want to study,

Collect data by using the quadrats placed next to each other,

If your transect is long, you could place quadrats at regular intervals,

Collect data by estimating percentage cover,

Find mean number of organisms to cover each quadrat,

See if changing abiotic factors correlates with distribution of species.

Question 21

Estimating Percentage Cover?

Answer 21

Estimating the percentage of quadrat covered by the particular type of organism.

Question 22

Regular Intervals?

Answer 22

Placing something within a certain distance each time,

E.g. placing a quadrat every two metres because your transect is long.

Question 23

Human Activities That Affect Biodiversity?

Answer 23

Fertilisers,

Fish Farming,

Non-Indigenous Species.

Question 24

Biodiversity?

Answer 24

Variety of living organisms in an ecosystem,

E.g. Amazon has high biodiversity.

Question 25

Fertilisers?

Answer 25

Nitrates are put into fields to help plants grow,

If too much fertiliser is used and it rains, the nitrates can find their way into rivers and lakes,

This causes eutrophication.

Question 26

Eutrophication?

Answer 26

Fertilisers enter the water and cause excess nutrients (excess nitrates),

The nitrate cause algae to grow fast and block out the light,

Plants can’t photosynthesise due to lack of light and start to die and decompose,

With more food available, microorganisms (bacteria) that feed on decomposing plants increase in number and use up the oxygen in the water,

Organisms that need oxygen for aerobic respiration die (including animals such as fish).

Question 27

Fish Farming?

Answer 27

Fish farms can reduce biodiversity in the surrounding area,

Food is added to nets to feed fish which produces waste,

Both food and waste can leak into open water and act as a breeding ground for parasites,

Parasites can get out of the farm and infect wild animals, sometimes killing them,

Predators are attracted to the nets and can become trapped and die,

Farmed fish can escape and cause problems for wild population of indigenous species,

Sometimes fish farms are held in large tanks.

Question 28

Non-Indigenous Species?

Answer 28

A species that doesn’t normally occur in a certain area.

Question 29

Indigenous Species?

Answer 29

Species that normally occurs in an area,

They are also referred to as “native” species.

Question 30

Problems Of Introducing Non-Indigenous Species?

Answer 30

They can out compete the indigenous species for food and shelter,

They can prey on native species which might cause a lower biodiversity,

Can bring new diseases to a habitat,

Often infect and kill indigenous species.

Question 31

Human Activities That Maintain Biodiversity?

Answer 31

Reforestation,

Conservation Schemes.

Question 32

Reforestation?

Answer 32

Forest is replanted,

Forests generally have high biodiversity because they contain a wide variety of trees and plants,

Deforestation reduces habitat and reforestation helps to restore it,

Reforestation schemes needs to be carefully planned to maximise positive effects,

E.g. Replanting a variety of trees will result in a higher biodiversity.

Question 33

Conservation Schemes?

Answer 33

Protecting a species natural habitat,

Protecting a species in a safe area that is outside of their natural habitat (e.g. zoos),

Introducing captive breeding programmes to increase numbers,

Seed banks to store and distribute the seeds of rare and endangered plants.

Question 34

Maintaining Biodiversity Benefits?

Answer 34

Protecting food supply and chain,

Providing future medicines,

Cultural aspects (bald eagle in the USA),

Ecotourism (people pay and travel to see different plants and animals),

Providing new jobs.

Question 35

The Nitrogen Cycle?

Answer 35

Nitrogen-Fixing Bacteria and lightning turns nitrogen in atmosphere to nitrates in soil,

Nitrifying bacteria turns ammonia into nitrites and then into nitrates in soil,

Plants absorb nitrates and use it to build amino acids and proteins,

Animals eat plants and use these amino acids to make animal proteins,

Decomposers (bacteria) break down the dead organisms, urea in waste and plants into ammonia,

Nitrifying Bacteria turns ammonia into nitrites then into nitrates in soil again,

In some cases, denitrifying bacteria turns nitrates back into nitrogen.

Question 36

In What Cases Do Denitrifying Bacteria Usually Work?

Answer 36

In waterlogged soil.

Question 37

Decomposers?

Answer 37

Decomposes proteins and urea (in waste) into ammonia,

Ammonia forms ammonium ions in solution that plants can use.

Question 38

Nitrifying Bacteria?

Answer 38

Turn ammonia in decaying matter into nitrites and then into nitrates.

Question 39

Nitrogen-Fixing Bacteria?

Answer 39

Turn nitrogen in the atmosphere into ammonium ions.

Question 40

Denitrifying Bacteria?

Answer 40

Turn nitrates in the soil back into nitrogen gas,

This usually happens in waterlogged soil because this is where denitrifying bacteria is often found.

Question 41

Nitrogen Fixation?

Answer 41

Process of turning nitrogen from the atmosphere into nitrates,

This can happen two ways:

• lightning,
• nitrogen-fixing bacteria.

Question 42

Nitrogen Fixing Bacteria Is Found?

Answer 42

In the soil and in the nodules on roots of legume plants,

Legume plants include peas and beans,

When these plants decompose, nitrogen stored in the and their nodules is returned to the soil.

Question 43

Relationship With Bacteria And Legumes?

Answer 43

Legume plants have a mutualistic relationship with the nitrogen-fixing bacteria,

The bacteria gets food (sugars) from the plant and the plant gets nitrogen gas from the bacteria to make proteins.

Question 44

Farmers Increase Nitrates In Soil?

Answer 44

Crop Rotation,

Fertilisers.

Question 45

How Do We Reduce Waterlogged Soil Risk?

Answer 45

Improve drainage systems in soil.

Question 46

Crop Rotation?

Answer 46

Different crops are grown in soil each year in a cycle,

Legume plants and planted in soil to increase the nitrogen-fixing bacteria,

This helps put nitrates back into the soil,

These nitrates are used to grow crops.

Question 47

Fertilisers?

Answer 47

Spreading animal manure or compost on fields recycled the nutrients left in the plant and animal waste,

Decomposition returns the nutrients,

Artificial fertilisers containing nitrates can be used too but they are expensive,

Harbour Process is an example of an artificial fertiliser being created,

Nitrogen gas is turned to ammonia during this process.

Question 48

Why Is Nitrogen Common In Atmosphere?

Answer 48

Atmosphere contains 78% nitrogen gas,

Nitrogen is extremely interactive so a lot is created but not much is broken down,

It’s so un reactive that plants cannot use it to make proteins,

It must be turned into nitrogen containing ions such as nitrates.

Question 49

Why Are Droughts An Issue?

Answer 49

Sea water is too salty to drink so we rely on precipitation,

We use methods in times of drought such as Desalination.

Question 50

Desalination?

Answer 50

Removes mineral ions (such as salt) from the sea water,

An example of this is thermal desalination.

Question 51

Thermal Desalination?

Answer 51

Another name is distillation,

Water is boiled in a large, enclosed vessel,

Water evaporated,

Steam rises to the top of vessel while the salt is left at the bottom,

Steam travels down a pipe from top of the vessel and condenses,

Condenses into pure water.

Question 52

The Water Cycle?

Answer 52

Energy from sun makes water evaporate and turns it into water vapour,

Water vapour is also realised from plants during transpiration,

Warm water rises,

Water vapour condenses when it cools to form clouds,

Water falls as precipitation,

Water drains back into sea where process starts over.

Question 53

Osmosis?

Answer 53

Osmosis is the movement of water across a partially permeable membrane from a higher concentration of water to a lower concentration of water,

However, when there is a higher concentration of salt, there is a lower concentration of water,

So osmosis is also movement from a lower concentration of salt to a higher concentration of salt.

Question 54

Reverse Osmosis?

Answer 54

Salt water is treated to rid of solids,

Water is fed at high pressure into a vessel containing a partially permeable membrane,

Pressure causes water molecules to move in opposite direction to osmosis,

Water moves from a high concentration of salt to a low concentration of salt,

Membrane forces the water through but leaves the mineral ions behind.

Question 55

How Are Materials Recycled?

Answer 55

Living plants and animals are made of elements taken from the environment,

These elements are turned into complex compounds (carbohydrates, fats and proteins). They’re passed along the food chain when they die,

Decomposers break down waste products and dead organisms which allows the elements to be passed back into the food chain.

Question 56

Decomposers Are Usually?

Answer 56

Microorganisms such as bacteria.

Question 57

Carbon Cycle?

Answer 57

Only way carbon is taken from the atmosphere is through photosynthesis in plants. This powers the whole cycle,

Plants use CO2 to create fats, proteins and carbohydrates,

Eating passes the carbon through the food chain,

Respiration from plants and animals realises CO2 into the atmosphere,

Decomposers break down plants and animals which allows them to take in carbon. This carbon is released by respiration of the decomposers,

Fossil fuels are burned and release carbon. This is called combustion,

Decomposition of materials allows a habitat to contain nutrients and is sustainable to live in.