Populations and Sustainability (6) Flashcards
What is population size?
Population size is the total number of organisms of one species in a habitat?
What abiotic factors affect population size?
light, water, space etc.
How do abiotic factors affect popultion size?
When they are ideal for a species, organisms can grow fast and reproduce successfully. However, when they are not ideal, organisms cannot grow as fast or reproduce as successfully.
What is interspecific competition?
It is when organisms of different species compete with each other for the same resources
What is intraspecific competition?
It is when organisms of the same species compete with each other for the same resources.
How can interspecific competition affect population size?
Competition between two species can mean that the resources available to both populations are reduced. This means both populations will be limited by that factor, e.g, food. So, they have less energy for reproduction, and therefore, both populations compete against each other, making the population smaller than if there was only one species present.
How can interspecific competition affect the distribution of species?
If two species are competing but one is better adapted to its surroundings than the other, the less well adapted species is likely to be outcompeted- it won’t be able to exist alongside side thebettwe adapted species.
What is the carrying capacity?
This is the maximum stable population size of a species that an ecosystem can support is called the carrying capacity.
How does intraspecific competition work?
- The population of a species increases when resources are plentiful
- As the population increases, there will be more organisms competing
- Eventually resources will be limiting, and the population begins to decline
- A smaller population means less competion so the population starts to grow again
What is predation?
This is where an organism kills and eats another organism.
By what process are the predator/prey population sizes controlled?
Negative feedback
How are predator/pray populations controlled by negative feedback?
- As the prey population increases, there is more food for predators so the predator population grows.
- As the predator population increases, more prey is eaten so the prey populations then begin to fall.
- This means there is less food for the predators, so their population decreases and so on.
What are limiting factors for increasing population size?
- abiotic factors
- biotic factors
limiting factors determine the carrying capacity of an ecosystem
What is conservation?
Conservation is the protection and management of ecosystems so that the natural resources in them can be used without them running out. This means that the natural resources will still be avaliable for future generations.
What kind of process is conservation?
Conservation is a dynamic process, so it needs to be constantly adapted to the constant changes that occur within ecosystems.
What processes does conservation involve?
- conservation involves the management of ecosystesms through controlling how resources are used and replaced
- reclamation involves the restoring of ecosystems that have been damaged or destroyed so they can be used again
Why is conservation important for the economy?
Ecosystems provide resources for lots of things that humans need. These resources are economically important as they are traded on a local and global scale. If the ecosystems are not conserved, the resources that we use now will be lost, so there will be less trade in the future.
Why is conservation important socially?
Many ecosystems bring joy to lots of people because they’re attractive to look at and people use them for activities. The species and habitats in the ecosystems may be lost if they aren’t conserved, so future generations won’t be able to use and enjoy them.
Why is conservation important ethically?
- Some people think we should conserve ecosystems simply because it is the right thing to do.
- Some people think we have a moral responsibility to conserve ecosystems for future generations, so they can enjoy and use them.
How is preservation different to conservation?
Preservation is the protection of ecosystems so they’re kept exactly as they are. Nothing is removed from a preserved ecosystem and they’re only used for activities that don’t damage them.
How can woodland ecosystems provide resources in a sustainable way?
- Trees are cleared in strips or patches, woodland grows back more quickly in smaller areas between bits of existing woodland than it does in larger open areas.
- The cleared strips or patches aren’t too large or exposed, lots of soil erosion can occur on large areas of bare ground. IF the soil is eroded, newly planted trees won’t be able to grow
- Timber is sometimes harvested by coppicing, cutting down new trees in a way that lets them grow back. This means new trees don’t need to be planted.
- Native tree species tend to be planted in preference to non-native species. This is better for biodiversity because native species have long established interactions with other native species, so their presence should help species thrive in an area. Also, some species might not adapt to the presence of non-native tree species.
- Planted trees are attached to posts to provide support, and are grown in plastic tubes to stop them being eaten by grazing animals, this makes it more likely the trees will survive to become mature adults
- Trees are not planted too close together, this means the trees aren’t competing with each other for space and resources, so they are more likely to survive.
What is the current problem with the way we fish?
Fish stocks are declining because we are overfishing. This means that there is less fish for us to eat, the oceans food chains are affected and at some species of fish may dissapear altogether in some areas. To tackle this problem, we need to maintain fish stocks at a level where the fish continue to breed.
What is sustainable food production?
This is when you have enough food without using resources faster than they renew
What are fishing quotas?
There are limits to the amount of certain fish species that fishermen are allowed to catch. They are supposed to help to conserve fish species by reducing the numbers that are caught and kille, so the populations aren’t reduced too much and the species aren’t at risk from becoming extinct.
How are fishing quotas decided?
Scientists study different species and decide how big their populations need to be for them to maintain their numbers. Then they decide how many it is safe for fishermen to take without reducing the population too much.
How are international agreements linked to fishing quotas?
International agreements are made that state the amount of fish each country can take, and where they’re allowed to take them from.
What are the problems with fishing quotas?
- Fish of the wrong size are still caught, but are thrown back injured or dead
- New rules can ban this and the whole catch will have to be brought ashore to be counted against the quota.
How can controlling the mesh size of nets prevent overfishing?
- there are limits to the size of the fish net depending on what is being fished. This is done to reduce the number of unwanted and discarded fish that are accidentally caught. Using a bigger mesh size willl let the unwanted species escape. it also means that younger fish will slip through the net allowing them to reach breeding age. But it can be difficult to determine exactly how big t he mesh size should be in areas where several different fish species ar fished for at hte same time. And two nets, each of which meets refulations, could be used inside the other- effectively reducing the reported mesh size.
What is the Terai Arc?
It is an area of forest and grasslands on the border between Nepal and india. A variety of plants and animals are found there, including endangered species like the Bengal tiger and Asian elephant. Nearly 7 million people also live in this area and many of them depend on the forest’s resources to survive.
How has human needs affected the Terai Arc?
Areas of the forest are being cleared for housing and development, which brings humans and animals closer together, increasing the conflict between them.
How has conservation efforts affected the Terai Arc?
Conservation charity the WWF have worked with local people to help balance their needs with conserving the forest and it’s wildlife. For example, the charity has provided people with things like solar cookers adn biogas generators, so they don’t need to use wood from the forest as fuel. Farmers are encouraged to plant mint hedges around thier crops to keep animals away.
What is the Maasai Mara?
It is a national reserve in Kenya. It is a large area of grassland which is home to huge populations of wildebeest and zebra, as well as lions and cheetahs. The Masai Mara is named after the Maasai people who live in the area.
How has human needs affected Maasai Mara?
The Maasai people traditionally earn a living by raising livestock, such as cattle. This can bring them into conflict with conservationists.
How has conservation efforts affected Maasai Mara?
Conservation trusts are working with the Maasai people to help them make money from their land through conservation and ecotourism projects rather than farming, and to farm sustainably. So, the economic needs of the Maasai people are met, while still allowing the area to be conserved.
What is the UK peat bogs?
Lots of upland parts of the UK are home to peat bogs, areas of wet peat. These peat bogs store water and carbon dioxide and are home to lots of different plants and animals.
How have human needs affected the UK peat bogs?
Farmers use the peat bogs to graze sheep and deer. However this can lead to conflict with conservationists because overgrazing causes loss of moss specices , soil compaction and general peat bog erosion.
How have conservation efforts affected the UK peat bogs?
Recent govenment funded programmes, like the environmental stewardship scheme, have given farmers money to use the peat bogs in a sustainable way.
What are the Galapagos Islands?
They are a small group of islands in the pacific ocean. Many rare species of animals and plants have evolved there that can’t be found elsewhere. In the past, islands have attracted sailors, explorers, and scientists, but recently the number of inhabitants and tourists to the islands has increased considerably.
How have humans affected the ecosystems in the galapagos?
- non native animals introduced by humans eat the native animal populations, which causes a decrease in the native species
- non native plants introduced by humans compete with the native plants, causing a decrease in their populations.
What methods of control are in place to prevent human impact in the galapagos?
- erradication programmes have removed wild goats and wild dogs which compete with native species. Quinine trees are also regualted using chemical herbicides as well as uprooting younger trees.
- When people visit the Galapagos National Park, they are expected to follow a list of rules, which includes not bringing any live plants or animals onto the islands, or moving them between the islands. People are also only allowed to visit the Galapagos National Park in the company of a licensed guide.
What is antarctica?
Antarctica is the world’s southernmost continent. It has a unique icy landscape with plants and animals that have adapted to its harsh conditions.
How have humans affected the ecosystems in antarctica?
- Visitors to Antarctica have caused pollution in the past by dumping sewage into the sea and leaving rubbish. Shipping incidents have led to oil spills, which severely affect wildlife
- hunting, whaling, and fishing have all reduced the wildlife population in the area.
What methods of control are in place to prevent human impact in antarctica?
- All waste apart from food waste and sewage must be taken away by ship for disposal in other countries. Many research stations now treat their sewage before releasing it, to reduce its effects on the environment
- ships that use thick oil as a fuel are now banned from antarctic waters, heavy oil spills are likley to cause more damage and be harder to clean up than spills of lighter fuels.
- There are tourist attractions
- hunting and whaling have been banned for some time now, although fishing continues.
What are the lake district and snowdownia?
The lake district and snowdonia are beautiful national parks, both are areas of hills and lakes, with the lake district in North West England and Snowdonia in wales. Both also attract millions of visitors per year.
How have humans affected the ecosystems in the lake district and snowdonia?
- Many of the visitors to the Lake District go walking on the region’s footpaths. This leads to the erosion of the footpaths and the loss of soil from hillsides. Soil that ends up in waterways and lakes can disturb the pH of the water, causing knock on effects for wildlife. As the paths become harder to walk on, people can start to ramp and destroy the sensitive vegetation on either side of the paths.
- It is a similar story in snowdonia- a lot of rain falls in the snowdonia hills, which leads to the erosion of the paths. Walkers often trample the surrounding vegetation as they try to walk around the floods.
What methods of control are in place to prevent human impact in the Lake District and snowdonia?
- In the Lake District, conservation charities and the Lake District National Park Authority attempt to carry out regular repair and maintenance work on the paths and encourage the regrowth of damaged vegetation. Walkers are also educated about the importance of sticking to the paths and not taking short cuts, as these increase erosion
- In snowdonia, volunteers have dug drains next to the paths to prevent them from flooding.
