Biodiversity for AS biology

Notes on biodiversity for AS biology for OCR (unit 2 of course).

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Biodiversity and evolution
A species is a group of individual organisms that are very similar in appearance, anatomy,
physiology, biochemistry and genetics, whose members are able to freely interbreed and
produce fertile offspring.
A habitat is the place where the individuals of a species live. The locality is specific and the
conditions are also specific to the organisms that live there. This means that organisms are
well adapted to their habitat. The definition of a habitat is `the place where an organism
What is biodiversity?
Biodiversity refers to the variety of life/ living organisms within an area. Biodiversity is about
the structural and functional variety of the living world - i.e. the degree of nature's variety.
There are three different levels of biodiversity:
1. The diversity of habitats ­ this is the number of different habitats within an area. This
must be considered because the organisms present in an area depend on the living
conditions. Different habitats have different living conditions.
2. The species diversity ­ this is the number of different species within an area and the
abundance of each of these species in the area.
3. Genetic diversity ­ this is the variety of alleles within a species or population of a
Collecting data on biodiversity
It's important to collect data on biodiversity but it's too time consuming to evaluate a
whole habitat, especially if the organisms are mobile. This means that samples of
populations are taken instead. From this sample, estimates about the whole of the habitat
are made. Below is how estimates are made:
1. Choose an area of the habitat to sample. The sample should be chosen at random to
avoid bias results. This will make it more likely that the sample is representative of
the population that you are sampling.
Perhaps you could divide the habitat into a grid and then use a random
number generator and random letter generator to select coordinates. The
sample could then be taken from the site at these coordinates.
2. Record the number of different species or the number of individuals of each species.
However, how you do this depends on what you are counting:
You would use a quadrat for plants on the ground - this is a square frame that
is placed onto the ground. First you identify the plants within the frame and
then you measure their abundance
You'd use a pitfall trap for insects on the ground ­ this consists of a small
container that is buried under the surface of the soil, with the rim just below

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Water should be placed at the bottom to prevent the animals
from climbing out. It should be sheltered from rain to prevent it filling up with
water in times of rainfall.
You'd use a sweepnet for flying insects. A pooter can be used in addition to
this to trap the animals before they crawl or fly away
You'd use a net for aquatic animals
3. Repeat the process ­ taking as many samples as possible increases the reliability
4.…read more

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Global biodiversity:
Global biodiversity is the total number of species on Earth. This includes the number of both
names and unnamed species. It is agreed by many scientists that there are a number of
species that are undiscovered or are known, but have not yet been named.
Different scientists have different estimates for the number of different species on Earth.…read more

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­ either positively by the introduction of new
crops that previously could not survive in the area's conditions, or negatively,
with certain plants potentially becoming unable to live in the new conditions,
reducing the source of food for certain animals
The importance of biodiversity:
There are many reasons why it is very important to maintain biodiversity:
Economic reasons:
o Many species of animals and plants are important to the global economy ,
with products being derived from plant and animal species traded on both a…read more

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There are people who believe that we have a moral responsibility to conserve
biodiversity for human generations
o Other people believe that biodiversity should be maintained for religious and
spiritual reasons
Aesthetic reasons:
o There are many people who believe that we should conserve biodiversity
because it brings joy to millions of people
Pleasant, attractive environments tend to bring lots of joy to others,
and are generally rich in biodiversity.…read more

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With the need to maintain biodiversity rising, especially due to the growing human
population and increased development globally, there are two main types of conservation:
1. In-situ conservation ­ this is the conservation of a species on site, by protecting
them in their natural habitat. Methods of in-situ conservation include:
Establishing protected areas like national parks.…read more

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Botanic gardens ­ these are controlled environments that are used to grow a
variety of rare plants for the following purposes:
In the botanic gardens endangered and even extinct in the wild plants can be
grown and then reintroduced into suitable habitats
Seed banks ­ it is possible to freeze seeds for over a century without losing
their fertility.…read more

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It is easier to check on the health on the species and ensure that the
organisms have enough food etc to survive
The individuals can be treated for diseases
Breeding can also be manipulated e.g.…read more

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The convention provides governments with guidance on how to conserve
CITIES agreement:
CITIES stands for Convention in International Trade in Endangered Species
This agreement aims to increase the international cooperation in regulating the trade
of wild animal and plant specimens
Member countries of this agreement all made it illegal within their countries to kill
endangered species
Species are helped to be conserved by this agreement by:
o Limiting trade through licensing
o Making it illegal to import products that are made from endangered species…read more


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