Final Exam Review The Finale

Chapter 20 Lesson 3 Energy in Ecosystems

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

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

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

Chapter 21 Lesson 1 Populations

What defines a population? Biosphere Ecosystems Community Populations

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

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

Chapter 21 Lesson 2 Changing Populations

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

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

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

Chapter 21 Lesson 3 Communities

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

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

Genetics The Final Frontier

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

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

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

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

Punnett Square Illustrates all of the possible genetic combinations

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