Transcript Biodiversity1 - onlinebiosurgery

What do the following species have in common?
Let’s visualise a pond dip
Explain the terms biodiversity and endemism and
describe how biodiversity can be measured within a
habitat using species richness and within a species using
genetic diversity, eg variety of alleles in a gene pool.
Biodiversity appears to be a buzz word but do you know
what it actually means?
Biodiversity comprises of every form of life, from the smallest
microbe to the largest animal, the genes that give them there
specific characteristics and the ecosystems they are part. This
includes diversity within species, between species and of
ecosystems.
The Convention on Biological Diversity
In a pond dip
Although the number of different species is a useful basic
measure, the concept is much more.
Differences between
•Individuals of a species
•Between populations of the same organism
•Communities
•Between ecosystems.
Why is it so important?
You should know already that all organisms in an ecosystem are
interlinked. But what is not as obvious is that all ecosystems are
interlinked on a larger scale across the earth.
Look at transpiration
Are some species more important than others?
Normally you think about important species such as …….
However, those further down the food chain are more important
Eg. the simple
Jungle burger
Fig wasp
Key Stone Species
Plays a major role in the survival of
kelp forests
Caledonian Forest
Scots Pine
Are some places more important than others?
www.biodiversityhotspots.org
Many papers published
Are some places more important than others?
Fact!
In an area of the Amazon Rainforest of a size less that of 4 tennis
courts there are ………… different species of tree found.
In temperate rainforests there is between …………
In Boreal rainforests there is ……………..
A picture for the ladies!
Norman Myers identified a number of Biodiversity Hotspots.
Unfortunately the areas correspond with areas where
people live
Measuring Biodiversity
Species Richness
The number of species in a given habitat
Salmon
Lizards
Species Evenness
Species Evenness
Species
Wood A
Wood B
Wood C
Blue Tit
25
20
11
9
17
7
4
7
20
17
23
22
0
18
0
0
50
12
3
27
0
8
0
0
Robin
Wren
Blackbird
Willow Warbler
Green Tit
Blackcap
Song Thrush
Can you compare woodlands A, B and C and comment on their diversity.
A diverse community will have high species richness and high evenness .
Managed
Natural
Oak
50
15
Ash
10
15
Sycamore
25
0
Field Maple
2
15
Hazel
3
20
Small Leaved Lime
0
8
Wild Service
0
9
Common Hawthorn
5
0
Midland Hawthorn
0
10
Holly
2
8
Beech
3
0
100
100
Total
Simpson's Diversity Index
A community dominated by one or two species is considered to be less diverse
than one in which several different species have a similar abundance.
Simpson's Diversity Index is a measure of diversity which takes into account the
number of species present, as well as the relative abundance of each species.
As species richness and evenness increase, so diversity increases.
n = the total number of organisms of a particular species
N = the total number of organisms of all species
The value of D ranges between 0 and 1. With this index, 1 represents infinite
diversity and 0, no diversity.
n = the total number of organisms of a particular species
N = the total number of organisms of all species
Problems
Not constant
Time of day (nocturnal)
Time of year
Migration
Techniques
Some Questions
1. The term biodiversity is often used in the media simply as the
number of species of living organisms. Explain why this gives
a limited picture?
2. Draw a flow chart to show the impact of sea otters on kelp
forests and explain why they are regarded as key stone
species.
3. Explain how high biological productivity and rapid mutation
rates can explain how areas of high biodiversity such as
tropical rainforests come about.
4. Explain how areas of high bird diversity and high bird
endemism come differ and why this might be.