1. Relationships between populations
7th Grade Science

2. 3 main relationships
Symbiosis
Predation (Predator/Prey)
Competition

3. Our goal for Symbiosis is to answer these questions:
What is symbiosis?
What are the different kinds of symbiosis?
What are some examples of symbiosis?

4. Symbiosis What it means: Two organisms that live together
Temporarily or for a longer time
At least one of the organisms benefits from the relationship

5. What are the different kinds of symbiosis?
Mutualism
Commensalism
Parasitism
both organisms benefit
one organism benefits
one organism benefits
one organism is unaffected
one organism is harmed

6. Organism One Organism Two
Mutualism
Organism One Organism Two

7. Organism One Organism Two
Commensalism
Organism One Organism Two

8. Organism One Organism Two
Parasitism
Organism One Organism Two

9. What symbiotic relationship is this?
Acacia Plant & Ants
The ants lay eggs on acacia tree so they get a nice safe place for their eggs. The acacia covers the infected area with brown flesh (called a gall.) The plant has to use valuable resources to create the gall.
parasitism
What symbiotic relationship is this?

10. What symbiotic relationship is this?
Loa Loa Worm & Human
This worm infects human the blood stream and gets a nice warm safe home there. The human may go blind or have other complications as a result.
What symbiotic relationship is this?
parasitism

11. Predator-prey relationships

12. Predation - (Predator/Prey)
Learning Objectives
Be able to describe the relationship between predators and their prey.

13. Animals that eat other animals
Populations of animals are often limited by the amount of food.
What are animals that eat other animals called?
predators
What are the animals that predators eat called?
prey
To do: Define the words Predator and Prey and give an example of each.

14. Prey Adaptations – General
Prey have adaptations to detect and prevent being eaten by predators.
mimicry
venomous coral snake
scarlet kingsnake
speed & keen senses
camouflage
warning colors & patterns

15. Predator Adaptations – General
Predators have adaptations to catch and consume their prey.
birds of prey have keen eyesight and sharp beaks and talons
camouflage allows predators to blend in with their surroundings
venomous snakes have poisonous venom to subdue their prey
kingsnakes are immune to the venom of venomous snakes
treefrogs have special pads on their feet so they can cling to vertical surfaces

16. Can you find the camouflaged predators?1 3 2 4 8 6 7 5

17. This struggle for resources is called competition.
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.

18. Who competes?
Competition for resources between members of different species is called interspecific competition.
Competition for resources between members of the same species is called intraspecific competition.
Different species = Interspecific Same species = Intraspecific

19. 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.

20. 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