1. AGENDA May 15 Objective: Explain the forces that affect population dynamics within an ecosystem. Objective: Explain the forces that affect population dynamics within an ecosystem. 1. Biomes Homework 1. Biomes Homework 2. Begin Chapter 5: Communities and Populations 2. Begin Chapter 5: Communities and Populations 3. Homework and Review 3. Homework and Review –Food Web Projects –Study your Notes 4. BIOLOGY EOC is almost here! 4. BIOLOGY EOC is almost here!

2. Chapter 5: Populations and Communities

3. Useful Definitions Population – Group of organisms that all belong to the same species and live in a specific area. Population – Group of organisms that all belong to the same species and live in a specific area. Steady State – Growth rate is zero Steady State – Growth rate is zero Population remains stable Population remains stable

4. Exponential Growth Ideal conditions for growth and reproduction. Ideal conditions for growth and reproduction. Rapid increase in a population. Rapid increase in a population.

5. Logistic Growth Page 1034 Most populations go through a number of growth phases. Most populations go through a number of growth phases. Carrying Capacity - # of individuals that can be supported in a given environment. Carrying Capacity - # of individuals that can be supported in a given environment.

6. Factors that Control Population Growth Density-Dependent Limiting Factors Density-Dependent Limiting Factors Affect large populations more strongly than small populations Affect large populations more strongly than small populations 1. Competition – individuals compete 1. Competition – individuals compete 2. Predation – Sources of food 2. Predation – Sources of food 3. Parasitism – living off other organisms 3. Parasitism – living off other organisms 4. Crowding and Stress – overpopulation leads to limited resources 4. Crowding and Stress – overpopulation leads to limited resources

7. Predator/Prey Relationships Almost every animal serves as a food source for another one. Almost every animal serves as a food source for another one. These species have coexisted for many years. These species have coexisted for many years. Accustomed to each other’s strengths and Accustomed to each other’s strengths and weaknesses. weaknesses. Defense vs. Defense vs. Counterdefense Counterdefense

8. The Best Defense is a Good Defense PreyPredator PreyPredator Shells, poisonous skin,Stronger jaws, digestive Shells, poisonous skin,Stronger jaws, digestive Barbs, Camouflageenzymes, keen eyesight, Barbs, Camouflageenzymes, keen eyesight, venom venom Natural Selection…. Natural Selection…. Adaptations that allow individuals to best survive and reproduce in their natural environments. Adaptations that allow individuals to best survive and reproduce in their natural environments.

9. Section 3: Interactions Among Communities Populations within a Populations within a community interact with community interact with one another in many ways. one another in many ways. Plants compete for water, Plants compete for water, nutrients, and sunlight. nutrients, and sunlight. Herbivores compete Herbivores compete for food and space. for food and space. Carnivores compete for the Carnivores compete for the herbivores often with more than one species targeting the same prey. herbivores often with more than one species targeting the same prey.

10. Interactions 1. Commensalism: One 1. Commensalism: One organism benefits and the organism benefits and the other is unharmed. other is unharmed. 2. Mutualism: Two species live 2. Mutualism: Two species live together that benefit both together that benefit both organisms. organisms.

11. Interactions between Ecosystems Consider a pond in a forest. Consider a pond in a forest. The pond supports a whole range of plant and animal life. The pond supports a whole range of plant and animal life. Water enters the pond from a nearby stream. Water enters the pond from a nearby stream. Water runoff feeds a different stream or marsh. Water runoff feeds a different stream or marsh. Animals in the forest rely on the pond for food and water. Animals in the forest rely on the pond for food and water. Even birds that travel many miles benefit from this pond. Even birds that travel many miles benefit from this pond.

13. AGENDA May 18 Objective: Provide evidence as to why humans disrupt population dynamics. Objective: Provide evidence as to why humans disrupt population dynamics. 1. Predator – Prey Graphing Skills 1. Predator – Prey Graphing Skills 2. Chapter 6: Human Population Dynamics 2. Chapter 6: Human Population Dynamics 3. Homework and Review 3. Homework and Review –Food Web Projects –Study your Notes 4. BIOLOGY EOC is almost here! 4. BIOLOGY EOC is almost here!

14. Chapter 6: Humans in the Biosphere Humans affect the environments they inhabit. Humans affect the environments they inhabit. Massive number of trees cut down. Massive number of trees cut down. Destroyed plants that did not provide benefits. Destroyed plants that did not provide benefits. Dangerous/Wild animals were hunted and killed to protect humans and domesticated animals. Dangerous/Wild animals were hunted and killed to protect humans and domesticated animals. Logging around the world continues to threaten and destroy many native species of plants and animals.

15. Factors that Determine Population Growth Humans create enormous demands on the natural resources of planet Earth. Humans create enormous demands on the natural resources of planet Earth. Birthrate versus Deathrate Birthrate versus Deathrate Earth’s population continues to increase threatening to use up many of its natural resources to meet the basic needs of life. Earth’s population continues to increase threatening to use up many of its natural resources to meet the basic needs of life. Earth’s population will double in the next half century at the current rates. 1.High birthrate 2.Low deathrate 3.Longer life-span

16. Human Population Growth Curve

17. Pollution Biodegradeable organic wastes such as sewage and food scraps can be broken down into essential nutrients Biodegradeable organic wastes such as sewage and food scraps can be broken down into essential nutrients Nonbiodegradeable ones cannot be broken down through natural processes (glass, chemicals, plastics.) Nonbiodegradeable ones cannot be broken down through natural processes (glass, chemicals, plastics.) Garbage dump site in Mexico City, Mexico.

18. Pollution Industrial chemicals, sewage waste, and the thermal pollution (burning of fossil fuels) The Greenhouse Effect (Carbon dioxide) Destruction of the Ozone Layer (Chloroflurocarbons are now banned) Extinction of Plant and Animal Species (Destruction of natural habitats)

19. Saving the Earth Going Green Going Green Conservation of land. Conservation of land. Protecting oceans and other bodies of water. Protecting oceans and other bodies of water. Using more biodegradeable products. Using more biodegradeable products. Breeding endangered species in safe environments. Breeding endangered species in safe environments. Banning hunting for sport. Banning hunting for sport. Joining the PTHS ENVIRONMENTAL CLUB! Joining the PTHS ENVIRONMENTAL CLUB!