Populations and Sustainability Flashcards
Factors that determine the size of a population
Abiotic factor= availability of light,water,space,temperature
Biotic = interspecific and infraspecific competition, pathogens
Carrying capacity
- the maximum population size that can be maintained over a period in a particular habitat
- limiting factors affect the carrying capacity
- population not subject to further succession
Interactions between populations
- predator-prey relationships:
1. When the predator population gets bigger, more prey are eaten.
2. The prey population then gets smaller, leaving less food for the predators.
3. With less food, fewer predators can survive and their population size reduces.
4. With fewer predators, fewer prey are eaten, and their population size increases.
5. With more prey, the predator population gets bigger, and the cycle starts again.
Interspecific competition= different species compete with each other for the same resources. Less resources for both species= lower population
- can also affect the distribution of species. The species better Adapted to its surroundings will outcompete the others. Both can not exist alongside each other
- intraspecific competition= the same species compete with the same resources.
Keeps the population size relatively stable.
- population of species increases when resources are plentiful but as the population increases more organisms competing for food and soave so eventually becomes limiting and the population declines
-smaller population means lesss competition so population begins to increase again
Conservation vs preservation
- conservation= management of nature to protect species and habitats
- preservation = land not to be used by humans as human access is prohibited
- leaves ecosystem untouched
Economic reasons to conserve biological resources
-ecotourism
-potential for future medicines
Social
- aesthetic reasons as people find ecosystems beautiful to look at
Ethical reasons to conserve biological resources
-humans have the moral responsibility to preserve biodiversity and stop extinction so future generations can enjoy
Sustainable timber production
- coppicing:
The trunk cut close to ground level: several new shoots will grow from cut surface;
process repeated after certain time; you need to protect young shoots from grazers; can be repeated indefinitely
- rotational coppicing= different area of woodland provide different types of habitats letting more light in and increasing the number and diversity of species.
- advantages:
-stems grow more rapidly than saplings;
• lifespan of tree extended
-fewer large trees means more light for smaller plants
• provides a variety of habitats
- Maintains biodiversity
• roots prevent soil erosion
- prevents succession
- selective felling= cutting down of selected, mature trees in a forest. This allows other trees to grow to maturity and also leaves enough for habitats for animals.
- replanting trees after felling
Sustainable fishing
-Introduce quotas- limits the number of
certain species of fish that can be caught. International agreement
-larger fishing nets to allow smaller fish the escape and reach maturity
-Fishing is only allowed at certain times of the year allowing the population to reach a sustainable level.
Masai Mara
-people earn a living by raising livestock such as cattle but overgrazing by livestock can destroy grass land for wildlife
- conservationist work with the massari people to llowaathem make money from their land through conservation and ecotourism projects rather than farming and to farm in a sustainable way .
- economic needs met by the people and the area is still conserved
The terai Arc in napal
-large population of people live there.
-areas of the forest are destroyed to make way for more housing,also animals may trample on their crop fields meaning they are more likely to be shot
-conservist charitys have provided people with solar cookrs and biogas generators so they dont need to use wood from the forest a fuel.
-farmers also are encouraged to plant mint hedges which animals dont like he taste of so our kept away
uk peat bogs
-peat bogs store water and carbon dioxide
-they take many years to form
- farmers use peat bogs to graze sheep and deers
- government-funded programmes has given farmers money to use peat in a more sustainable way to reduce water runoff and lower the amount of livestock using peat bogs
the Galapagos island
- humans have introduced non-native animal species which eat native species
-also non-native plants have been introduced which outcompete native plants
to control
- people have to folow rules like not bringing animals to the island
-some animals have to be quarantined e.g. dogs
Antarctica
- humans have caused pollulation
-large ships hav also caused oil spillages
-hunting,whaling and fishing of wildlife reduced their population
to control
-people must take their waste with them
-hunting and whaling banned
-large ships have been banned from the island
the lake district and snowdonia
- Humans have walked of footpaths causing the erosion of food paths
-in snowdownia large rainful has caused the erosion of footpaths
therefore humans trample of vegetation destroying them
to control
-authoritys attempt to regular repair and maintaince work on paths
-encourage regrowth of destroyed vegetation
- educated the people about sticking to paths and not taking short cuts
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