Download 1.-Biodiversity - Lesmahagow High School

National 5 Biology
Key Area 1:
Biodiversity and the Distribution of
Life
National 4 Biology
Key Area 2:
Impact of population growth and
natural hazards on biodiversity
National
4&5
outcomes
By the end of the lesson you
will be able to …..
• Define the word Biodiversity.
• Explain why a high level of biodiversity
is important to humans
Biodiversity
Life
Variety
Biodiversity is the total variety of all
living things on Earth
David Attenborough - Wonderful World – BBC 2:04
Why is high biodiversity
important?
Human rely on high biodiversity for numerous
reasons:
Products:
 Food
 Raw materials
 Medicines
Regulation of
ecosystems:
 pollinate crops
 absorbs CO2
gases
Cultural Benefits
 recreation and
tourism
National
4&5
outcomes
Can you now ….
• Define the word
biodiversity.
• Explain why a high
level of biodiversity
is important to
humans.
Quick Question
1. The total variety of all living things on
Earth is described as
A.
B.
C.
D.
An ecosystem
Biodiversity
A population
Competition
2. Give two reasons why humans depend on
a high level of biodiversity.
National
4&5
outcomes
By the end of the lesson you
will be able to …..
• Give examples of factors that affect
biodiversity
Factors that affect
biodiversity
1. Biotic and Abiotic Factors
Relating to living
things
• Food availability
• Predation
• Grazing
• Disease
• Competition for resources
Relating to NON living things
• Moisture
• Light Intensity
• pH
• Temperature
Can change
variety of
fish
species in a
pond
2. Natural Hazards
• Many natural
disasters (e.g. forest
fires) can decrease
biodiversity.
3. Human Influences
1. Habitat destruction – decreases
biodiversity by destroying where an
organism lives.
• “Habitat loss is probably the greatest
threat to the variety of life on this
planet today” WWF 2013
• removes an animals source of food and
their shelter.
• Many animals will die of starvation or
exposure.
2. Deforestation – decreases biodiversity by
removing large areas of forest
Deforestation in Kenya
• In 1963 10% of Kenya
was rich forest
• In 2006 only 1.7%
remained as untouched
forest
• Demand for hardwoods
• Employment & cash
crops
Deforestation (3:49)
3. Over fishing – decreases biodiversity by catching
too many fish and destroying habitats.
•Food and Agriculture Organization (FAO) estimate, over 70% of the
world’s fish species are either fully exploited or depleted
4. Intensive agriculture – decreases biodiversity by
using machinery, pesticides and herbicides to produce
large quantities of food crops.
Intensive agriculture lowers biodiversity by
• Encouraging large areas of ‘monoculture’
where only one type of crop is grown
• Increased use of pesticides and herbicides
• Eradication programmes (e.g. wolves and
badgers removed to protect livestock)
5. Genetic Pollution – decreases biodiversity by
introducing new genes into wild populations.
“In 2002 farmers' traditional maize varieties in
two remote Mexican states, Oaxaca and Puebla,
had been contaminated with DNA from
genetically modified (GM) maize. Genetic
pollution is alarming both because it is illegal
to grow GM maize in Mexico”
(http://www.foodfirst.org/en/node/53)
•Genetic pollution occurs
when genes from GM
crops/animals are passed
into wild populations.
•This can reduce
biodiversity because the
modified organisms could
out compete their ‘wild’
relative forcing them
into extinction.
6. Oil or chemical spills– decreases biodiversity by
introducing toxic chemicals that change the
environment.
Hawaii: molasses spill
• 12th September 2013
• 233,000 gallons of molasses spill into the water of
Honolulu Harbour from a pipeline supplying tankers
• Equivalent to 5,500 barrels of oil
Honolulu molasses spill (2:12)
National
4&5
outcomes
Can you now ….
• Give examples of
factors that affect
biodiversity
Quick Question
1. Name one biotic factor that can affect
biodiversity.
Food Availability or Predation or Grazing or Disease or
competition
2. What effect does deforestation have
on biodiversity?
It DECREASES biodiversity
3. Describe the effect habitat
destruction has on biodiversity.
It also DECREASES biodiversity because it destroys where an
organism lives. Organisms are left exposed and/or starving
By the end of the lesson you will
be able to …..
• Give examples of resources that animals
and plants compete for
• Define interspecific and intraspecific
competition and give examples of each
Competition
• Habitats have limited
supplies of the resources
needed by living
organisms.
• Organisms must compete
with others to get enough
of these resources.
Plants compete for:
Sunlight
Water
Space
Soil nutrients
Animals compete for:
Food & Water
Shelter
Territory
Mates
Different types of
competition
• Interspecific competition is when
individuals of different species compete
for the same resource in an ecosystem
• Intraspecific competition is when
individuals of the same species compete
for exactly the same resources
An example of Interspecific
Competition
The Grey squirrel
vs.
The Red squirrel
Red squirrel – 4:44
Competition between members of
different species
• Red and Grey squirrels compete for the same food...
– North American Grey squirrels were introduced to
Britain and competes with the native red squirrel
– The grey squirrels competes more aggressively for
food and have become more widely distributed
– Therefore the red squirrel is now in decline!
Can you now ….
• Give examples of
resources that
animals and plants
compete for
• Define interspecific
and intraspecific
competition and give
examples of each
Quick Question
1. What resources would animals compete
for?
Food/Mates/Shelter/ Territory
2. What is interspecific competition?
When members of different species compete for the same resource
3. Which type of competition is fiercest,
interspecific or intraspecific? Why?
Intraspecific
Quick Questions
1. Name one human activity that affects Biodiversity






Habitat destruction
Deforestation
Intensive agriculture
Over-fishing
Genetic pollution
Oil or chemical spills.
2. Describe how this activity affects biodiversity.
It causes it to decrease because ……..
By the end of the lesson you will
be able to …..
• Define the term endangered species.
• Give examples of ways to protect
biodiversity
• Give the advantages and disadvantages
of reintroducing a species to an
environment
Endangered Species
Species in danger of
becoming extinct.
Ways to prevent
extinction:
Wildlife reserves
Captive breeding
programmes
Re-introduction of
animals
Yellowstone: the return of the wolf 5:42
Factors
contribute
to species
What that
factors
contribute
to animals
becoming extinct….
becoming extinct?
•
•
•
•
•
•
•
Hunting or culling.
destruction of habitat
outbreaks of disease
declining birth rates
changes to their food source
adverse weather
pollution
Can you now ….
• Define the term
endangered species.
• Give examples of ways
to protect
biodiversity
• Give the advantages
and disadvantages of
reintroducing a
species to an
environment
Quick Questions
1. What is the difference between a biotic and
abiotic factor? Biotic factors relate to living things, Abiotic
factors relate to non living things
2. Sort the following factors into biotic and abiotic
Biotic
Grazing
Rainfall
Abiotic
Temperature
Predation
pH
Disease
By the end of the lesson you will
be able to …..
• Describe how the biotic factors, such
as predation, affect biodiversity.
• Interpret (describe the patterns shown
by) predator-prey graphs.
Predation
• Remember!
– Predator – an animal that
consumes another animal for
energy
– Prey – an animal that is hunted
and consumed by another
animal for energy
• Can affect biodiversity
• The numbers of prey and
predators are very closely
linked
Predator-Prey Interactions
• Ladybirds and aphids
Predator-Prey Interaction
• The number of predators depends on the number of prey
(and vice versa!).
• Predator numbers increase when there is lots of prey.
• Prey numbers increase when there are low numbers of
predators.
Can you now ….
• Describe how the
biotic factors, such
as predation, affect
biodiversity.
• Interpret (describe
the patterns shown
by) predator-prey
graphs.
Quick Questions
1. Define the word prey.
Animal that is hunted and eaten by another animal for energy
2. Define the word predator.
An animal that hunts and eats other animals for energy
3. Which line in the
graph shows prey
numbers?
A
4. Explain why predator
numbers are
increasing in the
highlighted area of
the graph More food available!
A
B
By the end of the lesson you will
be able to …..
• Define the word biome.
• Name (at least) three different biomes.
• Give two factors that influence the
global distribution of biomes on earth.
• Biologists divide the world into large natural
regions called biomes.
• These are two you may have heard of ….
Desert
Rainforest
Introduction to Biomes 3:09
How many biomes are there?
• Depends on who
you ask!
• For National
Biology we will be
looking at 8
different Biomes
Marine
Tundra
Rainforest
Biomes
Deciduous
Forest
Prairie
Polar
You are not required to know the individual biomes by name but must be
able give the definition for Biomes and name two factors that affect
their distribution.
Biomes
Biomes are the various regions of our planet
distinguished by their similar climate, fauna
(animal life) and flora (plant life).
Global distribution of biomes can be
influenced by …
• Temperature
• Rainfall
Can you now ….
• Define the word
biome.
• Name (at least)
three different
biomes.
• Give two factors
that influence the
global distribution of
biomes on earth.
Biomes of Our Earth: Major Life Zones .
Quick Questions
1. Define the word prey.
Animal that is hunted and eaten by another animal for energy
2. Define the word predator.
An animal that hunts and eats other animals for energy
3. Which line in the
graph shows prey
numbers?
A
4. Explain why predator
numbers are
increasing in the
highlighted area of
the graph More food available!
A
B
Quick Questions
1. Define the word Biome.
The various regions of our planet distinguished by their
similar climate, fauna (animal life) and flora (plant life).
2. Name three different biomes
Any three from …..
Tundra, Taiga, temperate deciduous forest, tropical savannah,
temperate grassland, desert, Mediterranean, tropical rainforest.
3. State the two environmental factors that control
the distribution of biomes.
Rainfall and temperature
By the end of this lesson you will
be able to…
• Define the word Ecosystem
• Name the different components
contained within an ecosystem
Biomes
• We have looked at biomes.
• Biomes are the various regions of our planet
distinguished by their similar climate, fauna
(animal life) and flora (plant life).
•Huge!! Within these biomes there are
smaller areas called ecosystems
Ecosystems
An ecosystem is a natural biological unit
which is made up of living and non-living
parts.
Oak Tree Ecosystem
Different animals
Different plants
All of these
different
organisms live
somewhere in
this ecosystem
Population
• A population is a group of the same
species that live in a habitat
• e.g. a population of rabbits or a
population of oak trees.
Community
• A community is all the populations of
plants, animals and micro-organisms
living together in an ecosystem
OAK TREE ECOSYSTEM
SOIL ECOSYSTEM
FRESH WATER ECOSYSTEM
An ecosystem is made up of:
Habitat
A place where an organism lives.
Population
The total number of one type of organism, e.g. all
the deer living in one ecosystem.
Community
The total number of ALL the organisms living in the
ecosystem.
Habitat + Community = Ecosystem!
Can you now ….
• Define the word
Ecosystem
• Name the different
components
contained within an
ecosystem
Quick Questions
1. Match the word with it’s meaning…..
A
The total number of one type of organism
1 Habitat
B
A place where an organism lives.
2 Ecosystem
C
an animal that consumes another animal for
energy
D
The total number of ALL the organisms
living in the ecosystem.
3 Prey
4 Predator
5 Population
6 Community
an animal that is hunted and consumed by
E
another animal for energy
F
A natural biological unit made up of living
and non living parts
By the end of this lesson you will
be able to…
• Define the word Niche
• Give examples of different niches
within an ecosystem
The African Savannah
• Home for several top predators…
How can one
ecosystem
support all
of these
different
predators?
• All of these animals are
predators
But…….
– They eat different prey
animals
– Different ways of
obtaining food
– Live in different habitats
– Are active at different
times of the day
They all have a different role
in their community - niche
Ecological Niche
• A niche is the role that an organism
plays within a community
• It includes:
– the use an organism makes of the resources
in its ecosystem, e.g. birds feeding at
different heights of the same tree
– An organisms interactions with other
organisms in the community.
• For example
– Predation
– Parasitism