1. Final Exam Review The Finale

2. Chapter 20 Lesson 3 Energy in Ecosystems

3. How does energy move in ecosystems? Flows in one direction Sun  producers  consumers Producers – photosynthetic, chemosynthetic Consumers – herbivores, omnivores, carnivores, detritivores, decomposers

4. How is the movement of energy in an ecosystem modeled? Food chain – One feeding relationship – Arrow shows relationships – Energy decreases Food web – Interconnected food chains in a community – Food choices

5. Modeling continued Energy Pyramid – Show the amount of energy available in each step of a food chain Steps: trophic levels – Bottom trophic level: producers (100%) – Next trophic level: consumers that eat producers (10%) Primary consumers – Highest trophic level: consumers that eat other consumers (1%) Secondary consumers

6. Chapter 21 Lesson 1 Populations

7. What defines a population? Biosphere Ecosystems Community Populations

8. What factors affect the size of a population? Competition Limiting factors

9. Population Information continued Measurement: catch-and-release, population density, sample count Biotic potential – no limits Carrying capacity overpopulation

10. Chapter 21 Lesson 2 Changing Populations

11. How do populations change? Population Increases – Birthrate – Exponential growth Population Decreases – Death rate – Extinction species – Threatened species – Engdangered species Movement and Migration

12. Why do human populations change? Birthrate Deathrate Movement Can increase carrying capacity of environment Positive and negative effects of human population increase Increases due to: – Medical care- Sanitation- Food -Resources

13. Human Populations continued Decreases due to: – Disease – Natural disasters – Environmental disasters/change Movement and Immigration

14. Chapter 21 Lesson 3 Communities

15. What defines a community? All living things in the same ecosystem at the same time Habitats – All the things you need to survive Niches – What you do to survive

16. How do the populations in a community interact? Energy Roles – Producers – Consumers Relationships – Predator-Prey – Cooperative – same species – Symbiotic Mutualism – both species benefits Commensalism – one species benefits Parasitism – one species benefits, the other is harmed

17. Genetics The Final Frontier

18. The Reproduction of Living Things Brief #3 – Traits and Genes

19. DNA & Chromosomes DNA – Chemical molecule – Double helix shape – Located in the nucleus – Mutation: a change in the DNA Chromosomes – Made from DNA

20. Genes Genetic instructions Determines the traits Connect the double helix Base pairs – A, T, G, C – A and T – G and C Dominant – controls Recessive - hidden

21. Traits Expression of the genes Usually made from two genes Dominant – Hides the expression of another trait – Dd or DD Recessive – Expression is hidden – Dd

22. Punnett Square Illustrates all of the possible genetic combinations

23. Don’t forget to look over the four packets: Horses and zebras Left-handedness Corn Genetically modified foods