Biodiversity Flashcards
(60 cards)
What is biodiversity?
It is the variety of living organisms present in an area
Importance of biodiversity
It helps to maintain a balanced ecosystem for all organisms as species are interconnected - they depend on each other for food, oxygen, and other materials needed to survive
Levels of biodiversity
- Habitat biodiversity
- Species biodiversity
- Genetics biodiversity
What is habitat biodiversity?
It is the number of different habitats found within an area.
What is specie biodiversity?
It is the number of different species within an area- species richness and the abundance of individuals of each species within that area
What is genetic biodiversity?
It is the variation of alleles within a species
Importance of genetic biodiversity?
It allows for better adaptations to a changing environment so more individuals are likely to survive and reproduce increasing species biodiversity
Equation for calculating biodiversity.
D= 1- ∑(n/N)^2, where;
∑= sum of
N= total number of organisms of all species
n= total number of organisms of a particular species.
What does the index values usually result in?
It usually results in a value between 0 and 1, where 0 represents no diversity and a value of 1 represents infinite diversity. The closer the to 1 the index is, the more diverse the habitat
If the biodiversity value is low, what does that tell us about a habitat?
If the index value is low, that means that habitat has: a small number of successful species, a simple food web and is relatively stressful with low ecological niches
If the biodiversity value is high, what does that tell us about a habitat?
IF the index value is high, that means the habitat has: a large number of successful species, a complex food web, is relatively benign with more ecological niches.
What is niche?
It refers to the specific role an organism plays within its ecosystem, encompassing how it obtains food, shelter, and interacts with other species and the environment
Factors affecting biodiversity
- Climate change
- Agriculture
- Deforestation
- Human population growth
- Pollution
How does human population growth affect biodiversity?
As the human population growth increases, there is a greater demand for resources like food, homes, clothes and energy which means that a lot of resources are being used up faster than they can be replenished. This is an issue because it decreases species diversity and habitat diversity.
Example of how human population growth affects species diversity.
Overfishing: Fish populations are decreasing because of overfishing. This means that certain fish species population are decreasing and may even go extinct decreasing species diversity and genetic diversity within a population
How does pollution affect biodiversity?
Pollution affects biodiversity as it affects water, land, air and even kills plants and animals decreasing their biodiversity
What is deforestation?
It is the permanent removal of large areas of forest to provide land for farming, homes and roads.
How does deforestation affect biodiversity?
- It directly reduces the number of trees present in an area
- It reduces the number of animal species present in an area because their food source and habitat has been removed. This then has a knock on effect on other animals.
- The animals are then forced to migrate to other areas for survival decreasing the biodiversity from where they migrated to and increasing the biodiversity of where they are migrating to.
- If only a specific type of tree is felled, the species diversity is reduced.
What is monoculture?
It is the planting of only one specific crop species.
How does agriculture affect biodiversity?
- Habitats are lost as land is cleared to make way for large fields, reducing habitat diversity
- Local and naturally occurring plants and animals are seen as pests and weeds and so are killed with pesticides and herbicides reducing species diversity
- Traditional varieties of crops are lost because they do not make enough money and so are not planted any more, which reduces species diversity.
What is climate change?
It is the variation in the Earth’s climate
How does climate change affect biodiversity?
- Rising sea levels from melting ice caps could flood low-lying land, reducing the available terrestrial habitat.
- Higher temperatures and less rainfall would result in some plant species failing to survive, leading to drought-resistant species becoming more dominant. The loss of non-drought-resistant species would lead to the loss of some animal species dependent on them as a food source. They would be replaced by other species that depend on the xerophytes for food.
- A change in climate may mean that an area that was previously inhabitable becomes uninhabitable and vice versa. This causes species to migrate to a more suitable area causing a change in species distribution. If there isn’t a suitable habitat to migrate to, or the species can’t migrate because they can’t move eg plants, then the species may become extinct reducing biodiversity
What are the 3 main reasons for maintaining biodiversity?
- Aesthetic reason
- Ecological reasons
- Economic reasons
Explain aesthetic reasons for maintaining biodiversity
Areas rich in biodiversity provide attractive landscapes which attract tourists to the place which also have economical advantages
