ecology pt 2 Flashcards
describe a change in an environment:
- (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.
what environmental changes affect the distribution of a species in an ecosystem?
- temperature
- water availability
- composition of atmospheric gases
describe seasonal changes in the environment:
- 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.
describe the geographical climate as a change:
- 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.
describe human interaction as a change:
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.
how can living factors introduced by humans be a change?
- 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.
define biodiversity:
a measure of the variety of living organisms within a particular habitat, ecosystem, biome, or all over Earth.
- means ecosystem is stable, able to adjust to change quickly. if something happens to one of the species, the ecosystem will be fine, as there are so many other relationships the other species can rely on
what are the benefits of biodiversity?
- 200,000 species of animals act as pollinators, to pollinate apples and avocados, etc
- over 50% of our medical drugs are derived from living organisms
why are we now harming the Earth’s biodiversity?
- much larger population
- each individual now places more pressure on the environment than before. higher standards of living and consumption (e.g. clothes, phones, cars), meaning we use more raw materials and energy, so they can run out. we also produce more waste
what are the negatives of the waste produced by humans?
pollutes the land (landfill, nuclear waste), water (sewage, fertiliser run-off, industrial chemicals), and air (smoke from combustion, acidic gases from burning fossil fuels)
describe climate change as a threat to biodiversity:
- shifts ecosystems, and animal habitats, 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.
describe overexploitation as a threat to biodiversity:
- 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.
describe habitat loss as a threat to biodiversity:
- 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.
describe pollution as a threat to biodiversity:
- 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.
describe invasive species as a threat to biodiversity:
capable of causing extinctions of native plants and animals
- reduces biodiversity
- competition with native organisms for limited resources
- altering habitats.
why are biodiverse ecosystems important to us?
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.
why are biodiverse ecosystems good?
reduces the dependence of one species on another for food, shelter, and the maintenance of the physical environment.
describe the ‘aye-aye’:
- 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.
describe the ‘madagascar ground boa’:
- 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.
why are more resources being used and more waste being produced?
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.
where can pollution occur, and how does it affect plants and animals?
- 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.
how do humans reduce the amount of land available for other animals and plants?
building, quarrying (extracting stone or other materials from the Earth), farming, and dumping waste
- converting the land for our use also damages the environment
describe deforestation:
- cutting down of forests
- mainly happens in tropical regions, with tropical rainforests
- clears land for farming (raise cattle, grow food for cattle, grow crops for food, grow crops for biofuels)
- logging, which we can use to build, or to burn as fuel
what are the three main issues with deforestation?
- getting rid of these trees mean they’ll no longer photosynthesise. more CO2 will be left in the atmosphere, where it can contribute to global warming
- to clear forests, we usually burn them. this releases the carbon they were holding as carbon dioxide. this produced smoke can suffocate animals and pollute towns. it contributes to global warming
- a habitat, and therefore its biodiversity, has been destroyed, and entire species can become extinct
describe the problems with the destruction of peat bogs:
- often drained so they can be used as farmland to raise cattle/crops
- the water is removed, oxygen flows back into the soil, microorganisms can return and decompose the dead plants
- this releases the stored carbon as carbon dioxide
- ## this destruction of peat bogs also destroys the habitats of the organisms that live there, reducing biodiversity, and leading to the extinction of species
- sometimes we also purposefully remove the peat so we can burn it as a fuel, or use it as compost in the gardens
- this all releases CO2
- the destruction of peat bogs is happening much quicker than new ones can form
what are peat bogs?
areas of land where the soil is both acidic and waterlogged
- the microorganisms that usually decay plants cannot survive here, as it’s the wrong pH and the water stops air from getting in the soil, so there isn’t enough oxygen for aerobic respiration
- the partially rotted plants instead build up, and form a substance called peat. the carbon the plants took in during their lifetime is stored in this peat, instead of being released as CO2
PEAT IS GOOD, REDUCES GLOBAL WARMING
why has large-scale deforestation occurred in tropical areas?
- provide land for cattle and rice fields.
- grow crops for biofuels.
what are some of global warming’s biological consequences?
- 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, as species are unable to migrate/adapt quickly enough
how does global warming even occur? describe the greenhouse effect:
- the sun emits light rays that enter the Earth’s atmosphere.
- some heat bounces back from the Earth’s surface and is reflected back out into space
- some heat is absorbed by the ground
- some reflected rays are absorbed by greenhouse gases and trapped in the Earth’s atmosphere - this is normal an dis what keeps the Earth at a stable temperature. these gases then re-emit the rays in all directions, which are then absorbed by other greenhouse gases, and so on
- 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.
what does the term climate change refer to?
the effects of global warming on the climate (long term weather patterns)
- rare weather events become more common and severe
- sea level rise (higher temps cause more ice to melt, as the water in the oceans warms up, it expands, meaning its volume increases) - leads to flooding
what is a trophic level?
the position of an organism within a food chain.
- represented by numbers, starting at level 1 which is always a producer (plant/algae)
where does all of the energy in a food chain come from?
sunlight. this is used by producers to create their own biomass, then the energy is passed on to the next trophic level
why are food chains generally quite short?
as you move up a trophic level, energy is lost each time. there isn’t enough energy to sustain organisms at higher trophic levels, therefore food chains tend to only have 4 or 5
- only about 10% of energy from the previous trophic level gets passed onto the next
where are omnivores generally placed on a food chain?
- eat both producers and other animals
- generally placed at trophic level 3 (secondary consumers), as they do eat primary consumers, but also producers, so it’s not a perfect fit
what type of eater are the primary, secondary, and tertiary consumers?
primary consumers: herbivores (only eat producers)
secondary consumers: carnivores
tertiary consumers: carnivores
describe pyramids of biomass:
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.
what is biomass?
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.
- also refers to the total population weight of each trophic level, and that will get smaller each time too
- organisms don’t usually eat every part (don’t eat skeleton/teeth)
- the bits they do eat may not be absorbed properly, such as the scales on a snake. these bits are simply 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.
how do you calculate the efficiency of biomass transfer?
efficiency = (biomass transferred to next level / biomass available at the previous level) x 100
what are the disadvantages to maintaining biodiversity?
- expensive
- ## in order to maintain our current high standard of living, we need to damage the environment (e.g. must use fertilisers, pesticides in order to grow enough food. must dig huge mines to get to the rare metals needed for phones and computers)
- additionally, in developing countries, they must deforest to build homes, for firewood for cooking, and to grow crops. they rely on the environment for their livelihood
what can the individual do to maintain biodiversity?
- recycle more
- reduce the products we use, therefore reducing waste. this means less land is used for landfill, and less toxic chemicals from landfill can seep into the environment
how can governments maintain biodiversity?
set quotas controlling deforestation and carbon dioxide emissions
what is the importance of the reintroduction of field margins and hedgerows?
the government can enforce this by introducing new laws, and by paying farmers to do the right thing
- these increase biodiversity as they provide alternative food sources and habitats compared to the one crop growing in the field
describe the protection and regeneration of endangered habitats:
- can go alongside breeding programmes, or we wouldn’t even need a breeding programme in the first place, as all of the organisms there would be safe
- protects areas such as coral reefs and mangroves
describe breeding programmes:
- set up for endangered species, reducing the chance they’ll go extinct
- breed animals in captivity to safely rebuild their numbers
- eventually re-introduce them to the wild, where they can join their old population or form a new one
PROBLEM:
- unless the natural habitat they came from is safe, the population will simply decline again
define ‘food security’ and its threats:
when all people are able to access enough safe and nutritious food to meet their requirements for a healthy life, in ways the planet can sustain into the future
- increasing birth rates in some countries
- new pests and pathogens that kill crops/livestock, causing famine
- environmental changes (e.g. rainfall patterns can cause widespread famine in some countries, temperature changes) that decrease crop yield
- loss/cost of agricultural inputs (e.g. fertiliser, animal feed, fuels, pesticides). these costs are passed onto the consumer, meaning food becomes expensive
- war and conflict. disrupt the transportation and production of food, causing prices to rise and famine
- changing diets in HICs, meaning already scarce resources must be transported across the world to feed the wealthy.
what threats impact food security?
- increasing birth rates in some countries
- new pests and pathogens that kill crops/livestock, causing famine
- environmental changes (e.g. rainfall patterns can cause widespread famine in some countries, temperature changes) that decrease crop yield
- loss/cost of agricultural inputs (e.g. fertiliser, animal feed, fuels, pesticides). these costs are passed onto the consumer, meaning food becomes expensive
- war and conflict. disrupt the transportation and production of food, causing prices to rise and famine
- changing diets in HICs, meaning already scarce resources must be transported across the world to feed the wealthy. additionally, there’s a greater demand for more resource intensive food, e.g. meat
what is factory farming, and its advantages and disadvantages?
- 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.
how can food production efficiency be increased?
- 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.
describe sustainable fishing:
- fish stocks in the ocean are declining, due to overfishing
- it’s important to maintain fish stocks at a level where breeding continues, or certain species may disappear altogether in some areas
- opting for fish sourced from sustainable fisheries also helps maintain fish stocks
describe some sustainable fishing practices:
- increasing the size of fishing net holes. allows for the selective capture of adult fish, while enabling young fish to escape. allows young fish to grow and reproduce, maintaining the fish populations and contributing to the overall sustainability of fisheries
- fishing quotas. by setting limits on the amount of fish that can be caught, fishing quotas help maintain balanced ecosystems and ensure the long-term viability and sustainability of fish stocks
what are fish farms?
large enclosures/tanks designed to provide controlled environments for the growth of fish for human consumption. obtaining our fish from these farms allows wild fish stocks to recover
why are modern biotechnology techniques used to help create global food security?
enable large quantities of microorganisms to be cultured for food.
describe the production of mycoproteins as a sustainable food production method:
- the fungus ‘fusarium’ is cultures on an industrial scale in fermenters.
- these fermenters are large vats that can be kept at the optimum pH and temperature for the ‘fusarium’ to grow.
- grown in aerobic conditions and provided with glucose syrup as a food source (to allow the fungus to respire).
- the fungus grows and multiples within the fermenter.
- the fungal biomass is then harvested and purified to produce mycoproteins.
what are mycoproteins, and what are their advantages and disadvantages?
is a high protein meat 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.
what does GMO stand for?
genetically modified organism
describe genetically modified crops and microorganisms for food/medicinal food:
an organism whose genome has been modified
- 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).
describe the Bt toxin:
genetically modified so it produces toxins that kill insect pests that try to feed on it, increasing the crop yield. farmers don’t have to use as much chemical pesticide
- scientists have inserted the Bt (bacteria) toxin into some crop species
what other examples of improved traits in GMOs are there?
- drought resistance
- increased yield
- herbicide tolerance
- virus resistance
- flood resistance
why has global food production had to increase recently?
- human population has increased dramatically
- the average person nowadays eats much more than in the past. the food they eat is also much more resource intensive (e.g. meat and dairy instead of rice and grain)
