1. Complete your grid, using the words around the room.
Matching Challenge!
Complete your grid, using the words around the room.

5. Competition! Lesson Objectives
C/W
Date:……………………
Competition!
Lesson Objectives
To describe the impact of competition on a habitat.
To explain how the number of predators influence number of prey.
Success Criteria
List what plants and animals compete for.
Draw a graph to show how the number of predators and prey change.

6. What is competition?
All living things need natural resources, but the problem is that there is not enough for everyone. This means that individuals have to fight for them in order to survive.
This struggle for resources is called competition.

7. What do animals compete for?
There are four resources for which animals compete. What are they?
food
water
mates
land (territory)
Which resource is not relevant for interspecific competition?
Photo credit: © 2006 Jupiterimages Corporation
Members of different species will not compete for mates.

8. What do plants compete for?
Competition between plants may be less noticeable than competition between animals but it still takes place. What four things do plants compete for?
light
water
minerals
space
Photo credit: © 2006 Jupiterimages Corporation

9. Who competes?
Competition occurs between members of different species. This is called interspecific competition.
Competition also occurs between members of the same species. This is called intraspecific competition.

10. Game Time! 2 different coloured splints: Red and yellow
Coloured paper on the floor: same colour as the splints
Cover the floor with the paper and distribute the splints.
The class get into small groups of 4.
Each group is given a colour, plastic cup and pair of tweezers.
Competition to which group can get the most number of splints. They go up one at a time and can only use the tweezers and no kneeling to get the splints.
Afterwards you can talk about the competition between the students and how did it change? Is that like animals in the wild?

11. Pyramids!
Food chains and food webs show the feeding relationships in a community. But they do NOT tell us how many living organisms are involved.

12. A “Pyramid of Numbers”
A pyramid of numbers shows how many animals or organisms we are talking about.
For example, consider the following food chain:

13. A pyramid of numbers for this food chain would look like this:
Owl = 1
Voles = 5
Grass = 10

14. Understanding pyramids of numbers
In a pyramid of numbers, the length of each bar represents the number of organisms at each trophic level in a specified area.
As a single tree can support many organisms, this food chain produces an unbalanced pyramid.

15. Consider the food chain:
Another example:
Consider the food chain:
Grass Rabbit Fox Fleas
Lots of fleas
One fox
Some rabbits
Lots of grass

16. Pyramid of Number Challenge
Using your lego, make pyramid of number for the food chains above.
Use the key to model the pyramid of number for each food chain..
Grass = 10
Rabbit = 5
Fox = 1
Oak tree = 1
Caterpillar = 50
Robin = 10
Owl = 1
Lettuce = 50
Slug = 10
Thrush = 2
Cat = 1
Flea = 100
What are the problems in modelling a pyramid of number using Lego?
What are the problems in using pyramid of numbers to represent a food chain?

17. Pyramid Of Number Challenge
Make your pyramid of numbers for the food chains (a,b,and c) using Lego.
Answer the two challenge questions.
In your book, write out the food chain and sketch using a ruler your pyramid of number for each food chain.
Challenge: Complete worksheet.

18. Numbers or biomass? Teacher notes
This activity provides illustrated examples of pyramids of biomass and pyramids of numbers. It could be used to allow students to draw comparisons between these two methods of representing food chains.

19. Solution = Pyramid of biomass
Problems!
Model:
Disadvantages of using pyramid of numbers:
- It doesn’t take into account the size of organisms.
Solution = Pyramid of biomass
Takes into account the mass of an organism at each level of the food chain.

20. What are pyramids of numbers?
Pyramids of numbers are a quantitative way of representing food chains.
They record the number of organisms at each trophic level in a specified area.
What are the problems of representing food chains in pyramids of numbers?
Pyramids of numbers only give an accurate impression of the flow of energy in a food chain if the organisms are of similar size. Measuring the biomass at each trophic level can give a more accurate picture.

21. Understanding pyramids of biomass
In a pyramid of biomass, the length of each bar represents the amount of organic matter – biomass – at each trophic level in a specified area.
At each trophic level, the amount of biomass and energy available is reduced, giving a pyramid shape.

22. What is a predator
and prey?

23. The size of the two populations are very closely linked.
Predators and prey
A predator is an animal that hunts and kills other animal for food. The animal that is eaten is the prey.
For example, lynxes are a type of wild cat that hunt snowshoe hares in northern parts of North America.
Photo credit (left and right): © 2006 Jupiterimages Corporation
Teacher notes
See the ‘Adaptation’ presentation for more information on general adaptations of predators and preys, including the lynx and snowshoe hare.
The size of the two populations are very closely linked.
Why do you think this is?

24. What are prey and predators
What are prey and predators?? Can you think of an example from this food web.
chiffchaff
owl
blue tit
stoat
spider
ladybird
moth larva
vole
aphid
plants

25. Is it a prey or a predator?

26. Adaptations of the lynx
How are lynxes adapted for catching snowshoe hares?
excellent binocular vision for judging distances
warm thick furry coat protects from the cold
sharp teeth and claws for puncturing flesh
very strong hind leg muscles capable of pouncing 6.5 metres!
Photo credit: © 2006 Jupiterimages Corporation
extra large paws act as snow shoes

27. Adaptations of the snowshoe hare
The snowshoe hare lives in northern parts of North America. How is it adapted to avoid predators such as lynxes?
greyish-brown fur turns white in winter for camouflage
large ears help in detecting predators
monocular vision with a wide field of view to see predators approaching
Photo credit: © 2006 Jupiterimages Corporation
large furry feet act as snow shoes and protect the soles from cold

28. excellent binocular vision for judging distances
greyish-brown fur turns white in winter for camouflage
sharp teeth and claws for puncturing flesh
monocular vision with a wide field of view to see predators approaching
extra large paws act as snow shoes
large ears help in detecting predators
warm thick furry coat protects from the cold
large furry feet act as snow shoes and protect the soles from cold
very strong hind leg muscles capable of pouncing 6.5 metres!
Excellent vision
High Speed
High speed
Camouflage
Weapons
Defence

29. Adaptations of the lynx

30. Adaptations of the snowshoe hare