1. National 5 Biology
Unit 3 – Life on Earth
Section 14 - Ecosystems

2. Section 3. 14 – Ecosystems Pupils should be able to:
State the definitions of the ecological terms: species, biodiversity, population, producer, consumer, herbivore, carnivore, omnivore, predator, prey, food chain and food web.
Describe what an ecosystem is and how all the organisms in a particular habitat are interdependent.
Describe how population numbers can disrupt food webs
State what is meant by the term niche and how an organism’s niche relates to the resources it requires.
Describe predation and the relationship of predator and prey.
Describe what interspecific competition is between plants and animals
Describe what intraspecific competition between plants and animals.
State that intraspecific competition is more intense than interspecific.
By the end of this section you should be able to:

3. Variety of Life = Biodiversity

4. Biodiversity of Scotland

5. What makes a Species Unique?
Species - a group of organisms in which two individuals are capable of reproducing fertile offspring, typically using sexual reproduction.
Designer Dogs – Labra doodle (mongrel)
Liger

6. Human Needs My House – My Habitat
Habitat – the non-living (abiotic) part, i.e. the physical area in which organisms live
In pairs discuss what there is in your house that helps you to survive.
Note down your
ideas on the white boards.

7. Survival List

8. People and their habitats
People can live all over the world.

9. We can do this because we are able to build homes for different conditions.

10. Also we can change our clothes to best suit the temperature around us.
Animal skin and fur act as insulators and keep heat in.
White clothes reflect the heat

11. Uses of Plants
All animals must eat to get energy but green plants get their energy from the sun.

12. What is a Food Chain?
A food chain represents the transfer of energy through a series of organisms in a community (a group of organisms living in the same environment).
It usually starts with a producer (an organism that manufactures simple food by a process such as photosynthesis) and ends with a top consumer. Producers are eaten by herbivores or primary consumers. Carnivores may be secondary, tertiary or quaternary consumers.

13. Food chains always start with a producer (green plant).
The lettuce is eaten by the slug, the slug is eaten by the bird.
The arrow shows the direction of energy flowing from one organism to another.

14. Food Chains A food chain shows what is eaten.
All living things need to feed to get energy to grow, move and reproduce. But what do these living things feed on?
Smaller insects feed on green plants, and bigger animals feed on smaller ones and so on. This feeding relationship in an ecosystem is called a food chain. Food chains are usually in a sequence, with an arrow used to show the flow of energy.
Food Chains
A food chain shows what is eaten.
The fly is eaten by the thrush.

15. Food Chains
Food chains

16. Food Webs A food chain is not the same as a food web.
A food web is a network of many food chains and is more complex. It shows how all the organisms are interconnected.
In the diagram, the arrows show the direction of energy flow. It points to the animal doing the eating.

17. Producer (Green Plant)
Food Webs
Tertiary Consumer
Secondary Consumer
Primary Consumer
Predator
Producer (Green Plant)
Prey

18. What Happens if Something Disrupts a Food Web?

19. a - What is an Ecosystem?
An ecosystem includes all of the living (biotic) things (plants, animals and organisms) in a given area, interacting with each other, and also with their non-living (abiotic) environments (weather, earth, sun, soil, climate, atmosphere).

20. Ecosystems
A small scale ecosystem such as a pond, puddle, tree trunk, under a rock etc.
It all starts with the sun
Plants are known as producers as they can make their own food using the energy from the sun
Small animals, such as pond snails and water boatmen (primary consumers) eat the plant life.
Frogs and small birds eat the fish and larvae (tertiary consumer)
Dragonfly larvae and small fish, such as goldfish eat the insects (secondary consumers)

21. A medium scale ecosystem such as a forest or large lake.

22. Ecosystems
A very large ecosystem or collection of ecosystems with similar biotic and abiotic factors (biome)

23. What is a Niche?
A Niche is - the role an organism plays within a community, including the use it makes of the resources and its interactions with other organisms.
What resources would each of the following require to survive?

24. Predation predator prey
All the energy needed by living things comes from the sun.
Green plants are called producers because they are able to produce their own food by sunlight.
Consumers must consume plants or other animals in order to obtain the energy they receive.
An animal which hunts another animal for food is called a __________.
The hunted animal is called the _____.
predator
prey

25. Types of Consumer
Animals can be classed under 3 main headings according to what they eat.
_________ eat only plant material
_________ eat only animal material
_________ eat both plant and animal material
Herbivores
Carnivores
Omnivores

26. CARNIVORE
PREDATOR
HERBIVORE
PREY
DECOMPOSERS
OMNIVORE

27. Predator-Prey Relationships
Animals that are high up in food chains, such as the fox, tend to be hunters that are skilled at locating and killing their food. These hunters are called predators.
The animals on which the predator feeds are called their prey.
Prey animals tend to be well adapted to avoid the predator.
Common prey adaptations include camouflage or the ability to produce poisonous toxins.
Animals that are high up in food chains, such as the fox, tend to be hunters that are skilled at locating and killing their food. These hunters are called predators.

28. Prey population changes
Boardworks Science for Scotland: S1 and S2
Competition
Prey population changes
The relationship between predator and prey population numbers in a food web is very close and follows a cyclical pattern. This means that it rises and falls in a fairly regular cycle. Why is this?
The rabbit population changes due to both the vegetation growing season and changes in the fox population.
Individual rabbits must compete for food and mates, and must also avoid being killed by their predators, the foxes.

29. Predator population changes
Boardworks Science for Scotland: S1 and S2
Competition
Predator population changes
The fox population also follows a cyclical pattern very similar to the rabbit population. Why is this?
The fox is very dependent on rabbits for food, so as the rabbit population changes so does the fox population.
This is why the fox population rises and falls slightly after the rise and fall of the rabbit population.
How do cyclical rises and falls in population numbers affect the organisms in a larger food web?

30. Changes in food chain populations
Boardworks Science for Scotland: S1 and S2
Competition
Changes in food chain populations
The organisms in a food chain are dependent on each other. Changes in the number of organisms in one part of the food chain can have dramatic effects on the rest of the food chain.
fox
grass
rabbit
What would happen to the number of rabbits and foxes if all the grass died out?
Rabbit numbers would decrease because they would have less to eat and may starve or stop reproducing.
Fox numbers would also fall as there would not be as many rabbits to eat.

31. Food chain populations
Boardworks Science for Scotland: S1 and S2
Competition
Food chain populations

32. Snowshoe Hare and the Canadian Lynx

33. Questions
Describe what is happening to the population size of each animal
The snowshoe hair:
The Canadian Lynx
Why does the population of the lynx depend on the size of the hare population
As the number of lynx increase the number of hares decrease in response.
As the number of hares increase the number of lynx increases to a point then decreases
They are eating the hares so more hares = larger food source, therefore more lynx are able to survive to breed and raise more cubs.

34. What may occur when two species occupy the same ecological niche?
One species will be the most dominant and monopolise the resources, the other species may die out.
We call this competition

35. When does competition between organisms occur?
When resources are in short supply.

36. What will plants growing in the same habitat compete for?
Water
Space
Sunlight
Nutrients

37. What will animals living in the same habitat compete for?
Water
Food
Shelter
Mates

38. Describe the TWO different types of competition.
Interspecific competition
Individuals of different species compete for the same resource in an ecosystem.
Intraspecific competition
Individuals of the compete for exactly the same resources.
Watch the you tube video of Kruger park – lion the buffalo and the crocodile.

39. Which form is most intense and explain why.
INTRASPECIFIC because the organisms require exactly the same resources.

40. Food chains - terminology
Quick Quiz
Food chains - terminology

41. Term Definition Biodiversity
This is the huge variety of living things in a given area
Carnivore
An organism that feeds on animal material only
Competition
The activity or condition of striving to gain or win something by defeating or establishing superiority over others.
Community
The living (biotic) part e.g. all the organisms living in that habitat
Consumer
An animal that eats other plants and animals
Decomposer
organisms that break down dead or decaying organisms
Ecology
The study of relations of organisms to one another and to their physical surroundings.
Ecosystem
This is made up of all the living organisms and non-living parts of a habitat
Food Chain
This is a relationship where one organism feeds on the previous one in a series and in turn provides food for the next one.
Food Web
A series of interlocking food chains.

42. Intraspecific Competition Interspecific Competition
Term
Definition
Herbivore
An organism that feeds on plant material only
Intraspecific Competition
This occurs between members of the same species for the same resources. Intraspecific competition is more intense.
Interspecific Competition
This occurs between members of different species for the same resources.
Niche
This is the role that an organism plays within a community.
Omnivore
An organism that feeds on both plant and animal material
Organism
An individual, plant, or single-celled life form.
Predation
This is a biotic factor where one animal preys on others.
Predator
An animal that naturally preys on others.
Primary Consumer
Usually herbivores that feed on plants.
Population
All the members of a particular species in one habitat

43. Term
Definition
Prey
An animal that is hunted and killed by another for food.
Producer
Green plants that make glucose from sunlight/CO2 + H20
Secondary Consumer
These are mainly carnivores that prey on other animals.
Species
A group of organisms in which two individuals are capable of reproducing fertile offspring, typically using sexual reproduction.