ecology pt 2

Question 1

describe a change in an environment:

Answer 1

• (e.g. change in water/temperature) can cause a change in the distribution of organisms in that area.
• changes can be natural (seasonal/geographical change) or as the result of human activity.

Question 2

what environmental changes affect the distribution of a species in an ecosystem?

Answer 2

• temperature
• water availability
• composition of atmospheric gases

Question 3

describe seasonal changes in the environment:

Answer 3

• in temperate parts of the world, temperature, rainfall, and hours of daylight change dramatically between seasons.
• the distribution of plants and animals changes too - some migrate to avoid the cold, or in pursuit of more favourable conditions.

Question 4

describe the geographical climate as a change:

Answer 4

• involve many different factors including soil difference, soil structure or pH, the altitude or availability of water.
• many organisms have specific adaptations specific to certain areas of the world that enable them to survive and reproduce.

Question 5

describe human interaction as a change:

Answer 5

negative:
- global warming
- effects of acid rain on soil
- pollution from farms and factories

positive:
- maintaining rainforests
- reducing water pollution and monitoring its pH
- restricting access to certain sites of special scientific interest.
- conservation measures such as re-planting hedgerows and woodland.

Question 6

how can living factors introduced by humans be a change?

Answer 6

• can cause a change in environment where an organism lives, affecting distribution.
• new type of predator or disease-causing pathogen may be carried from one country or another and wipe out a species of animal or plant.
• different plants may be introduced and support a whole range of different species, or outcompete local species and reduce local biodiversity.

Question 7

define biodiversity:

Answer 7

a measure of the variety of living organisms within a particular habitat, ecosystem, biome, or all over Earth.
- should be stable, able to adjust to change quickly.

Question 8

describe climate change as a threat to biodiversity:

Answer 8

• shifts ecosystems, its services, and the specialist supports, threatening their continued health and survival.
• e.g. melting ice cuts off polar bears from their food supply.
• e.g. can worsen droughts, drying out the habitats of species.

Question 9

describe overexploitation as a threat to biodiversity:

Answer 9

• humans overexploit species to the point of extinction.
• worsens once healthy populations into or near extinction.
• e.g. overfishing. species which are overharvested are typically top predators, and the removal of these species can change an entire ecosystem.

Question 10

describe habitat loss as a threat to biodiversity:

Answer 10

• lessens the number of large, specialist species
• disrupts species interactions
• reduces trophic chain lengths
• alters predation rates
• when a habitat is destroyed, the carrying capacity for plants, animals and other organisms is reduced so their populations decline, sometimes to the point of extinction.

Question 11

describe pollution as a threat to biodiversity:

Answer 11

• air pollution can cause direct, irreversible harm to organisms.
• leads to habitat loss, alters ecological processes, and even drives climate change.
• life in the oceans is being threatened by water pollution and acidification due to the rising CO2 levels in the water.

Question 12

describe invasive species as a threat to biodiversity:

Answer 12

capable of causing extinctions of native plants and animals
- reduces biodiversity
- competition with native organisms for limited resources
- altering habitats.

Question 13

why are biodiverse ecosystems important to us?

Answer 13

we rely on these ecosystems for food, energy, medicine, fresh water and soil purification, and many other essential factors that enable us to survive.
- highly biodiverse places can cope better with changes - they’re more resistant to natural or human-related disturbances, such as climate change, and can recover quickly after major disasters.

• the future of the human species relies on us maintaining a good level of biodiversity. many human activities have been reducing biodiversity, and action has only been recently taken to stop it.

Question 14

why are biodiverse ecosystems good?

Answer 14

reduces the dependence of one species on another for food, shelter, and the maintenance of the physical environment.

Question 15

describe the ‘aye-aye’:

Answer 15

• only found in madagascar
• spend their lives in rainforest trees, where they curl up in a ball-like nest of leaves and branches.
• dig out wood-boring insect larvae beneath the bark.
• considered an omen of bad luck, so are killed on site by huntsmen. along with habitat destruction, they’re critically endangered.

Question 16

describe the ‘madagascar ground boa’:

Answer 16

• madagascar’s largest non-poisonous snake.
• lives in north and west madagascar, in open woodland, near water.
• shelters in fallen trees and debris piles, while it hibernates from may through to july.
• kills their prey by coiling their body around the victim and suffocating them to death, before swallowing them whole.
• threatened by deforestation, human population growth, and agricultural/industrial development.

Question 17

why are more resources being used and more waste being produced?

Answer 17

rapid growth of the human population and in the standard of living. unless this waste and chemical materials are properly handled, more pollution will be caused.

Question 18

where can pollution occur, and how does it affect plants and animals?

Answer 18

• water (from sewage, fertiliser or toxic chemicals).
• in air (from smoke, acidic gases)
• on land (from landfill and toxic chemicals)
• pollution kills plants and animals, reducing biodiversity.

Question 19

how do humans reduce the amount of land available for other animals and plants?

Answer 19

building, quarrying (extracting stone or other materials from the Earth), farming, and dumping waste.

Question 20

describe the problems with the destruction of peat bogs:

Answer 20

the destruction of peat bogs, and other areas, to produce garden compost, reduces the area of this habitat and thus the variety of different plant, animal, and microorganism species that live there (reduces biodiversity).

• the decay or burning of peat bogs also releases carbon dioxide into the atmosphere.

Question 21

why has large-scale deforestation occurred in tropical areas?

Answer 21

• provide land for cattle and rice fields.
• grow crops for biofuels.

Question 22

how does global warming occur, and what are some of its biological consequences?

Answer 22

• change in or loss of habitats due to an increase in extreme weather events.
• increasing temperatures causing extreme weather (e.g. super storms, flooding, droughts).
• ocean temperatures increasing, causing melting of polar ice caps (therefore rising sea levels, therefore flooding), coral bleaching.
• increased migration of species globally, resulting in an increased spread of pests and disease.
• decreases in biodiversity as food chains are disrupted and extinction rates increase.

Question 23

how does global warming even occur? describe the greenhouse effect:

Answer 23

• the sun emits rays that enter the Earth’s atmosphere.
• the heat bounces back from the Earth’s surface.
• some heat is reflected back out into space.
• some heat is absorbed by greenhouse gases and trapped in the Earth’s atmosphere - this is normal.
• however, as the levels of greenhouse gases in the atmosphere increase due to human activities, the Earth’s average temp rises above normal, causing global warming.

Question 24

what is a trophic level?

Answer 24

the position of an organism within a food chain.
- represented by numbers, starting at level 1 with plants and algae.

Question 25

describe pyramids of biomass:

Answer 25

constructed to represent the relative amount of biomass in each level of a food chain. level 1 will always have the most biomass. roughly 10% of each level’s biomass is transferred to the next level.
- producers transfer about 1% of the energy from light for photosynthesis.

Question 26

what is biomass?

Answer 26

living materials. it’s what is transferred from organism to organism.
- this decreases at each trophic level because the organism will inevitable use some of the biomass for itself before passing it on to the next organism.

• not all ingested material is absorbed, some is egested as faeces.
• some absorbed material is lost as waste, such as carbon dioxide and water in respiration and water and urea in urine.
• large amounts of glucose are also used in respiration.

Question 27

how can we maintain biodiversity?

Answer 27

• reintroduction of field margins and hedgerows in agricultural areas where farmers only grow one type of crop.
• reduction of deforestation and carbon dioxide emissions by some governments.
• recycling resources rather than dumping waste in landfill.
• creating a breeding program for species close to extinction
• protection and regeneration of endangered habitats.

Question 28

define ‘food security’ and its threats:

Answer 28

having more than enough food to feed the population.

• increasing birth rates in some countries
• new pests and pathogens that affect farming
• environmental changes (e.g. rainfall patterns can cause widespread famine in some countries) that affect food production
• loss/cost of agricultural inputs (e.g. fertiliser)
• war and conflict
• changing diets in HICs, meaning already scarce resources must be transported across the world to feed the wealthy.

Question 29

what is factory farming, and its advantages and disadvantages?

Answer 29

• involves keeping livestock in an enclosed area, such as a warehouse, and keeping such a huge population in there that they’re hardly able to move around.

advantages:
- chickens lose less biomass as they move less, therefore producing a greater yield of eggs.
- the farmer gets more profit, the eggs can be sold for cheaper, ensures food security.
- less land required to produce more food.
- low electricity cost. no heating required, as the chicken’s body heat keeps them warm.

disadvantages:
- if one chicken becomes ill, it can contaminate all of the other chickens and you’d need to dispose of them - big loss of profit.
- not natural conditions for chickens - welfare issues. unclean.

Question 30

how can food production efficiency be increased?

Answer 30

• restricts energy transfer from food animals to the environment.
• adding nutrients (e.g. ethene) and chemicals, fertiliser.
• increase light intensity
• mass farming livestock (factory farming). keeps animals warm, reduces movement.
• a high protein diet for animals.

Question 31

describe sustainable fishing:

Answer 31

• fish stocks in the ocean are declining.
• it’s important to maintain fish stocks at a level where breeding continues, or certain species may disappear altogether in some areas.
• control of net size and the introduction of fishing quotas (how many fish you’re allowed to catch).

Question 32

why are modern biotechnology techniques used to help create global food security?

Answer 32

enable large quantities of microorganisms to be cultured for food.

Question 33

describe the production of mycoproteins as a sustainable food production method:

Answer 33

1. the fungus ‘fusarium’ is cultures on an industrial scale in fermenters.
2. these fermenters are large vats that can be kept at the optimum pH and temperature for the ‘fusarium’ to grow.
3. grown in aerobic conditions and provided with glucose syrup as a food source (to allow the fungus to respire).
4. the fungus grows and multiples within the fermenter.
5. the fungal biomass is then harvested and purified to produce mycoproteins.

Question 34

what are mycoproteins, and what are their advantages and disadvantages?

Answer 34

is a meat or chicken substitute, but is essentially a protein made from fungus.

advantages:
- high in nutrients (e.g. fiber) and may help control blood cholesterol and blood sugar.
- can make you feel more full than actual meat (prevents overeating and weight gain).
- controls glucose and insulin levels.

disadvantages:
- could be quite high in salt and fat.
- recognised as a potential allergen, resulting in hives and anaphylaxis.

Question 35

describe genetically modified crops and microorganisms for food:

Answer 35

• a genetically modified bacterium produces human insulin. when harvested and purified, this is used to help treat people with diabetes.
• genetically modified crops could help to provide more food, or food with an improved nutritional value (e.g. golden rice contains a lot of vitamin A).