populations and sustainability Flashcards
factors affecting population size
The abiotic factors - temperature, oxygen and carbon dioxide concentration, light intensity, pH and soil conditions. Plants and animals are adapted to the abiotic factors within their ecosystem. These adaptations develop through the process of natural selection over time. The less harsh the abiotic factors, such as plenty of water and light, the larger the range of species and the larger the population sizes.
• Biotic factors - interspecific and intraspecific competition and predation also affect population size.
Interspecific competition is when members of different species are in competition for the same resource that is in limited supply. This could be competition for a habitat, food or water. The individual better adapted to the environment is more likely to succeed in the competition.
Intraspecific competition is when members of the same species are in competition for resources and a mate. Competition for a mate links to the courtship rituals. Individuals that are fitter will have more energy to perform a more impressive courtship ritual or may have fur or feathers in a better condition to attract a mate.
biotic factors
The interaction between predators and prey in a food web is represented in a predator-prey graph. Regardless of the species, the graph always follows the same pattern.
• The size of the predator and prey population both fluctuate
• There will be more prey than predators
• The size of the prey population will change before the predator population
conservation and preservation
Conservation is human actions and management to help maintain biodiversity. It involves sustainable development, whereby management of ecosystems is in place so that natural resources can be used by humans without them running out.
Preservation involves protecting an area by banning visitors. This is a very effective method of protecting ecosystems, but it prevents anyone from enjoying the area.
Conservation is important for three key reasons: *
1. Ethical: All organisms have the right to live, and conservation helps to ensure humans are not preventing this.
Conservation also helps ensure that future generations are able to experience
natural ecosystems.
2. Social: Enjoying the outdoors provides many physical and mental benefits to people.
3. Economic: Many medicines, foods, clothes and timber are sourced from natural ecosystems which would be lost if they are not conserved.
sustainable management
As the human population continues to increase, sustainable management is required to ensure that humans have food, shelter and infrastructure for survival without causing excessive loss of biodiversity and depletion of resources.
This relies on sustainable resources (renewable) so that future generations will have resources, environments are preserved, humans can live comfortably and less economically developed countries can develop without exploiting natural resources.
Sustainable timber production involves coppicing and pollarding. These techniques are when trees are cut close to the ground. This provides timber, but the plant is able to regrow and recover. On a larger scale, when larger forests are felled, only the largest trees are removed and new trees are replanted.
Sustainable fishing is essential to protect future fish populations whilst still providing a valuable protein-rich food source. Policiés in place include caught, increasing the size of the holes on ne sad not allowing to hing in certain areas or during mating season.
control of human activity 1
Masai Mara region in Kenya
• The Masai Mara National Reserve (MMNR) is an ecosystem under management to ensure conservation while not negatively impacting the needs of humans.
• For example.
the tsetse fly is a carrier of African
trypanosomiasis, and to reduce the spread acacia bushes have been removed as this is the habitat of the tsetse fly.
• As local tribes are not allowed in the park, they now have to graze their livestock on the outskirts of the park, instead of within it. This has enabled vegetation within the park to recover.
• Ecotourism is popular here, which provides economic benefits, but tourism must not exploit natural environments or local communities. The nature reserve also plays an important role in protecting endangered species, such as the black rhino. To help strike a balance, legal hunting involves the culling of overpopulated animal species.
control of human activity 2
• Along the southern border of Nepal is the Terai region, which has very fertile land and well-watered floodplains.
• This attracts many people, so management is needed to ensure that overpopulation does not harm the environment.
• There is sustainable forest management in this region to provide a livelihood for the locals whilst protecting the forest.
• To ensure agriculture can sustainably occur, farmers are encouraged to grow crops further up in the hills, improve irrigation, grow more than one crop variety to increase biodiversity and grow nitrogen-fixing crops (legumes).
control of human activity 2
• Along the southern border of Nepal is the Terai region, which has very fertile land and well-watered floodplains.
• This attracts many people, so management is needed to ensure that overpopulation does not harm the environment.
• There is sustainable forest management in this region to provide a livelihood for the locals whilst protecting the forest.
• To ensure agriculture can sustainably occur, farmers are encouraged to grow crops further up in the hills, improve irrigation, grow more than one crop variety to increase biodiversity and grow nitrogen-fixing crops (legumes).
control of human activity 3
• Peat bogs are carbon sinks that are wet and contain decomposing plant matter.
• As it is so carbon-rich, if it is dried out it is a good fuel source, however, this releases carbon dioxide into the atmosphere and it takes a long time for peat to reform.
• Peat has also been used in compost to improve the soil structure and acidity.
• To help protect peat bogs, the surface is kept as wet as possible and any small trees nearby are removed (to prevent absorption of water) there is also controlled grazing in the area.
environmentally sensitive ecosystems 1
Some ecosystems are less resistant to change and these are known as environmentally sensitive ecosystems.
Galapagos Islands
• These islands were produced from volcanic activities and have maina oldiversity as they have never been connected to the
• All the animals would have arrived by washing up from the mainland on vegetation. Most of the animals are reptiles.
• These native animals became at risk when whalers would come to the islands and kill animals for food, chop down trees to make fire and introduce non-native animals.
• To protect this ecosystem, it became a National Park with rangers to patrol the island, human access has been limited and there are strict controls over the movement of animals from the mainland.
environmentally sensitive ecosystems 2
• Antarctica has very harsh abiotic factors, being the coldest, windiest and driest continent.
• Barely any humans live here and plants only grow in ice-free regions. There are whales, seals and penguins here.
• Global warming is the biggest threat, but also the hunting of whales and seals and discharging of waste into the sea on exhibitions. The Antarctic treaty has been in place since the 1960s to help protect the ecosystem.
environmentally sensitive ecosystems 3
• Snowdonia National Park in Wales has rugged terrain, lakes, rivers and ancient woodlands and heathlands. To protect animals and plants, it became a National Park. Due to the beauty and mountains, it attracts many visitors every year.
The Park Authority helps prevent damage from tourism, provides economic benefits and also helps educate visitors on the Park’s qualities.
• The Lake District attracts many visitors due to the high mountains and lakes. The Park authority helps in the same way.
