1. National 5 Biology Key Area 1: National 4 Biology Key Area 2:
Biodiversity and the Distribution of Life
National 4 Biology
Key Area 2:
Impact of population growth and natural hazards on biodiversity

2. By the end of the lesson you will be able to …..
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

3. Biodiversity is the total variety of all living things on Earth
Life
Variety
Biodiversity is the total variety of all living things on Earth
David Attenborough - Wonderful World – BBC 2:04

4. Why is high biodiversity important?
Human rely on high biodiversity for numerous reasons:
Regulation of ecosystems:
pollinate crops
absorbs CO2 gases
Products:
Food
Raw materials
Medicines
Cultural Benefits
recreation and tourism

5. Can you now …. Define the word biodiversity.
National
4&5 outcomes
Can you now ….
Define the word biodiversity.
Explain why a high level of biodiversity is important to humans.

6. Quick Question
1. The total variety of all living things on Earth is described as
An ecosystem
Biodiversity
A population
Competition
2. Give two reasons why humans depend on a high level of biodiversity.

7. By the end of the lesson you will be able to …..
National
4&5 outcomes
By the end of the lesson you will be able to …..
Give examples of factors that affect biodiversity

8. 1. Biotic and Abiotic Factors
Factors that affect
biodiversity
1. Biotic and Abiotic Factors
Relating to living things
Relating to NON -living things
Food availability
Predation
Grazing
Disease
Competition for resources
Moisture
Light Intensity pH
Temperature
Can change variety of fish species in a pond

9. 2. Natural Hazards
Many natural disasters (e.g. forest fires) can decrease biodiversity.

10. 3. Human Influences

11. 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.

12. Deforestation in Kenya
2. Deforestation – decreases biodiversity by removing large areas of forest
Deforestation in Kenya
In % of Kenya was rich forest
In 2006 only 1.7% remained as untouched forest
Demand for hardwoods
Employment & cash crops
Deforestation (3:49)

13. 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
Overfishing the consequences (2:34)

14. Intensive agriculture lowers biodiversity by
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)

15. 5. Genetic Pollution – decreases biodiversity by introducing new genes into wild populations.
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.
“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” (

16. Hawaii: molasses spill
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)

17. Can you now …. Give examples of factors that affect biodiversity
National
4&5 outcomes
Can you now ….
Give examples of factors that affect biodiversity

18. Quick Question Name one biotic factor that can affect biodiversity.
What effect does deforestation have on biodiversity?
Describe the effect habitat destruction has on biodiversity.
Food Availability or Predation or Grazing or Disease or competition
It DECREASES biodiversity
It also DECREASES biodiversity because it destroys where an organism lives. Organisms are left exposed and/or starving

19. 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

20. Competition
Habitats have limited supplies of the resources needed by living organisms.
Organisms must compete with others to get enough of these resources.

21. Plants compete for:
Sunlight
Water
Space
Soil nutrients

22. Animals compete for:
Food & Water
Shelter
Territory
Mates

23. 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

24. An example of Interspecific Competition
The Grey squirrel vs.
The Red squirrel
Red squirrel – 4:44

25. 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!
vs.

26. Can you now ….
Give examples of resources that animals and plants compete for
Define interspecific and intraspecific competition and give examples of each

27. Quick Question What resources would animals compete for?
What is interspecific competition?
Which type of competition is fiercest, interspecific or intraspecific? Why?
Food/Mates/Shelter/ Territory
When members of different species compete for the same resource
Intraspecific

28. Quick Questions It causes it to decrease because ……..
Name one human activity that affects Biodiversity
Describe how this activity affects biodiversity.
Habitat destruction
Deforestation
Intensive agriculture
Over-fishing
Genetic pollution
Oil or chemical spills.
It causes it to decrease because ……..

29. 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

30. 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
The possible re-introduction of wolves into Scotland as a biological control (using Yellowstone data) is a good National 5 assignment topic.

31. What factors contribute to animals becoming extinct?
Factors that contribute to species becoming extinct….
Hunting or culling.
destruction of habitat
outbreaks of disease
declining birth rates
changes to their food source
adverse weather
pollution

32. 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

33. Quick Questions
What is the difference between a biotic and abiotic factor?
Sort the following factors into biotic and abiotic
Biotic factors relate to living things, Abiotic factors relate to non living things
Biotic
Abiotic
Grazing
Temperature pH
Rainfall
Predation
Disease

34. 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.

35. Predation Remember! Can affect biodiversity
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

36. Predator-Prey Interactions
Ladybirds and aphids

37. 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.

38. Can you now ….
Describe how the biotic factors, such as predation, affect biodiversity.
Interpret (describe the patterns shown by) predator-prey graphs.

39. Quick Questions Define the word prey. Define the word predator.
Animal that is hunted and eaten by another animal for energy
An animal that hunts and eats other animals for energy
3. Which line in the graph shows prey numbers?
4. Explain why predator numbers are increasing in the highlighted area of the graph A B A
More food available!

40. 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.

41. Introduction to Biomes 3:09
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

42. How many biomes are there?
Marine
Tundra
Prairie
Polar
Deciduous Forest
Rainforest
Depends on who you ask!
For National Biology we will be looking at 8 different Biomes
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.

43. Biomes
Biomes are the various regions of our planet distinguished by their similar climate, fauna (animal life) and flora (plant life).

44. Global distribution of biomes can be influenced by …
Temperature
Rainfall

45. 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.

46. Biomes of Our Earth: Major Life Zones .

47. Quick Questions Define the word prey. Define the word predator.
Animal that is hunted and eaten by another animal for energy
An animal that hunts and eats other animals for energy
3. Which line in the graph shows prey numbers?
4. Explain why predator numbers are increasing in the highlighted area of the graph A B A
More food available!

48. Quick Questions Define the word Biome. Name three different biomes
State the two environmental factors that control the distribution of biomes.
The various regions of our planet distinguished by their similar climate, fauna (animal life) and flora (plant life).
Any three from …..
Tundra, Taiga, temperate deciduous forest, tropical savannah, temperate grassland, desert, Mediterranean, tropical rainforest.
Rainfall and temperature

49. By the end of this lesson you will be able to…
Define the word Ecosystem
Name the different components contained within an ecosystem

50. 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

51. Ecosystems
An ecosystem is a natural biological unit which is made up of living and non-living parts.

52. Oak Tree Ecosystem Different animals Different plants
All of these different organisms live somewhere in this ecosystem

53. 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.

54. Community
A community is all the populations of plants, animals and micro-organisms living together in an ecosystem

55. OAK TREE ECOSYSTEM

56. SOIL ECOSYSTEM

57. FRESH WATER ECOSYSTEM

58. 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!

59. Can you now …. Define the word Ecosystem
Name the different components contained within an ecosystem
White boards!

60. Quick Questions Match the word with it’s meaning…..
The total number of one type of organism B
A place where an organism lives. C
an animal that consumes another animal for energy D
The total number of ALL the organisms living in the ecosystem. E
an animal that is hunted and consumed by another animal for energy F
A natural biological unit made up of living and non living parts 1
Habitat 2
Ecosystem 3
Prey 4
Predator 5
Population 6
Community

61. By the end of this lesson you will be able to…
Define the word Niche
Give examples of different niches within an ecosystem

62. How can one ecosystem support all of these different predators?
The African Savannah
Home for several top predators…
How can one ecosystem support all of these different predators?

63. They all have a different role in their community - niche
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

64. 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