Transcript LESSON 1 Defining biodiversity

Defining Biodiversity
What is the nature
and value of biodiversity?
Learning Objectives –
* To know & understand what biodiversity is
* To be able to explain the three ways in which
biodiversity can be measured
* To be able to use key terminology accurately and
confidently
Locate the habitat of the following
creatures on a world map
1. Fossa
2. Pink River Dolphin
3. Bengal Tiger
6. Sun Bear
4. Tibetan Fox
5. Kakapo
4.
3.
6.
2.
1.
5.
Mallomys giant rat
• A giant rodent five times the
size of a common rat has
been discovered in the
mountainous jungles of New
Guinea.
• The 1.4kg Mallomys giant rat
is one of two species of
mammal thought to be new to
science documented on an
expedition to an area
described as a "lost world".
• Conservationists also found a
pygmy possum - one of the
world's smallest marsupials on the trip to the remote north
of Papua province, Indonesia.
• 18 December 2007 - BBC
The Biodiversity found on Earth today consists of many millions of distinct
biological species, which is the product of nearly 3.5 billion years of
evolution.
Biological diversity means the variability among living organisms from all
sources and the ecological complexes of which they are part. This includes
diversity, within species, between species and of ecosystems
Genetic diversity
Species diversity
Ecosystem diversity
Biodiversity is often used as a measure of the health of biological systems.
Genetic diversity is a level of biodiversity that refers to the total number of
genetic characteristics in the genetic makeup of a species.
Genetic diversity and Biodiversity are dependent upon each other -- Genetic
Diversity within a species is necessary to maintain biodiversity.
Genetic diversity plays a very important role in survival and adaptability of a
species because when a species’ environment changes, slight gene variations
are necessary for it to adapt and survive. A species that has a large degree of
genetic diversity among its population will have more variations from which to
choose the most fit genes.
Species that have very little genetic variation are at a great risk. With very little
gene variation within the species, healthy reproduction difficult.
http://www.bbc.co.uk/lear
ningzone/clips/6244.html
Watch the clip, then describe how genetic
variation has helped this species to survive and
adapt
1. Genetic Variation exists among
individuals within giraffes – some have
short necks like a horse, others have
slightly longer necks.
2. All the giraffes are experiencing
competition for resources (food and space)
3. This competition would lead to the death
of some individuals (mainly shorter necked
ones, as their food is also eaten by all the
other short necked animals) while others
would survive (the longer necked ones
have an advantage as they can reach the
juicy leaves at the top!)
4. Individuals that have advantageous
variations are more likely to survive and
reproduce.
Species diversity is an index that incorporates the number
of species in an area and also their relative abundance.
Simpson's Diversity Index:
D = (n / N)2
n = the total number of organisms of a particular species
N = the total number of organisms of all species
A value of 0 indicates infinite diversity, a value of 1 indicates
no diversity
Ecosystem diversity refers to the diversity of a
place in terms of its variety of ecosystems or
habitats i.e what is the diversity of different
ecosystems within the UK, as opposed to the
diversity of species within these ecosystems.
advantages
GENETIC
Diversity
SPECIES
Diversity
ECOSYSTEM
Diversity
disadvantages
advantages
disadvantages
GENETIC
Diversity
•Allows an accurate picture of
diversity within a population (2)
•Helps explain how isolated
species eg birds have adapted
to new environments (10)
•Difficult to assess without
high level biological skills as
DNA is required (11)
SPECIES
Diversity
•A good general measure (4)
•Better to use a range of
indicator species (8)
•Better to use taxonomic
diversity eg 1 rodent, 2 bird, 1
lizard species = better than 4
bird species (7)
•Must compare similar sized
areas for a fair test (3)
ECOSYSTEM
Diversity
•A more complex measure as it
considers the interaction of
species within their
environment (1)
•Possibly more useful when
deciding which areas to protect
as has a wider focus (5)
•Difficult to know where the
boundary of the ecosystem
is (6)
•Species richness does not
cover species distribution or
interaction between species
•(9)
Defining Biodiversity
• http://www.daversity
code.com/
• What is meant by
the ‘web of life’?
Watch the clip
carefully then draw
a diagram to support
your answer.
Ecosystem Key Words
• Dominoes
Keep your cards to yourself – if you think
you have one that matches a domino that
has been laid down then put your hand up
and explain!