1. Ecology: Part 2

2. Chapter 4 Population BiologyPopulation Biology   4.1: Population DynamicsPopulation Dynamics  Section Objectives:  Relate the reproductive patterns of different populations of organisms to models of population growth  Predict effects of environmental factors on population growth.

3. Principles of Population Growth  A population is a group of organisms, all of the same species, that live in a specific area.  A healthy population will grow and die at a steady rate unless it runs out of food or space, or is attacked in some way by disease or predators.

4. What can limit growth?  Limiting factors, such as availability of food, disease, predators, or lack of space, will cause population growth to slow

5. Carrying capacity  The number of organisms of one species that an environment can support indefinitely  When a population overshoots the carrying capacity, then limiting factors may come into effect.  Deaths begin to exceed births and the population falls below carrying capacity Carrying capacity

6. Density factors and population growth  How organisms are dispersed can be important.  two kinds of limiting factors that are related to dispersal: density-dependent and density-independent factors.  Density-dependent factors include disease, competition, predators, parasites, and food.  Density-independent factors can affect all populations, regardless of their density.  Most density-independent factors are abiotic factors, such as temperature, storms, floods, drought, and major habitat disruption.

7. Organism Interactions Limit Population Size   1.Predation affects population size  Populations of predators the Lynx and their prey the Snowhare are known to experience cycles or changes in their numbers over periods of time Lynx Hare

8. Organism Interactions Limit Population Size II   2. Competition within a population  When only a few individuals compete for resources, no problem arises.  When a population increases to the point at which demand for resources exceeds the supply, the population size decreases.

9. Organism Interactions Limit Population Size III The effects of crowding and stress  These include aggression, decrease in parental care, decreased fertility, and decreased resistance to disease  become limiting factors for growth and keep populations below carrying capacity.

10. Chapter 5: Biological Diversity and ConservationBiological Diversity and Conservation What You’ll Learn   You will explain the importance of biological diversity   You will distinguish environmental changes that may result in the loss of species   You will describe the work of conservation biologists

11. 5.1: Vanishing SpeciesVanishing Species Section Objectives: Explain biodiversity and its importance.  Relate various threats to the loss of biodiversity.

12. Biological Diversity  Biodiversity refers to the variety of species in a specific area.  The simplest and most common measure of biodiversity is the number of different species that live in a certain area.  Areas around the world differ in biodiversity .

13. Where is biodiversity found?  Biodiversity increases as you move toward the equator.  Tropical regions contain two-thirds of all land species on Earth.

14. Importance to nature  Living things are interdependent  Living things can be niches for other living things.  Populations are adapted to live together in communities.  Scientists do know that if a species is lost from an ecosystem, the loss may have consequences for other living things in the area.

15. Importance to people  Biodiversity provides humans with food, clothing, shelter, oxygen, soil fertility, etc.  Biodiversity could help breeders produce additional food crops.  can be used to improve people’s health- some of which may provide future drugs. Penicillium

16. Loss of Biodiversity  Extinction is the disappearance of a species when the last of its members dies.  Extinction is a natural process and Earth has experienced several mass extinctions during its history.  However, the current rate of extinction is very high  Overexploitation of wildlife also threatens many species

17. Overexploitation of wildlife also threatens many species Loss of Biodiversity II Overexploitation of wildlife also threatens many species  A species is considered to be an endangered species when its numbers become so low that extinction is possible.  When the population of a species is likely to become endangered, it is said to be a threatened species.

18. Threats to Biodiversity 1. 1.Habitat loss The loss of tropical rain forests and marine habitats are especially devastating 2. Habitat fragmentation the separation of wilderness areas from other wilderness areas

19. Threats to Biodiversity II 3. Habitat degradation: the damage to a habitat by pollution.  Three types of pollution are air, water, and land pollution.

20. Air pollution  Pollutants enter the atmosphere in many ways—including volcanic eruptions and forest fires.

21. Air pollution II Rapid global warming could alter the entire biosphere  Burning fossil fuels is increasing the amount of CO 2 and other greenhouse gases in the air which increase global temperature negative effects:  Change in climate patterns  Melting of polar ice  Flooding of coastal regions  Increase in the rate of species loss

22. Air pollution III  Acid precipitation—has been linked to the deterioration of some forests and lakes.  Destruction of the ozone layer has increased the ultraviolet radiation reaching Earth’s surface.  probably results from the accumulation of chlorofluorocarbons -chemicals used in refrigeration and aerosol cans, and in certain manufacturing processes.

23. Water pollution  Excess fertilizers and animal wastes are often carried by rain into streams and lakes.  The sudden availability of nutrients causes algal blooms, the excessive growth of algae. ->  Detergents, heavy metals, and industrial chemicals in runoff can cause death in aquatic organisms.  Oil spills ->  Abandoned drift nets in oceans have been known to entangle and kill dolphins, whales, and other sea life.

24. Land pollution  Trash, or solid waste  The use of pesticides and other chemicals  Chemical pesticides are concentrated in food chains by biological magnification

25. Exotic species  People sometimes introduce a new species into an ecosystem, either intentionally or unintentionally.  These species can cause problems for the native species  these species can grow at an exponential rate due to the fact that they are not immediately as vulnerable to local competitors or predators as are the established native species.

26. Section ObjectiveSection Objective Describe strategies used in conservation biology. Conservation biology is the study and implementation of methods to protect biodiversity. Natural resources are those parts of the environment that are useful or necessary for living organisms.~ include sunlight, water, air, and plant and animal resources. 5.2: Conservation of BiodiversityConservation of Biodiversity

27. Conservation Biology Legal protections of species the U.S. Endangered Species Act became law in 1973. Preserving habitats the creation of natural preserves and parks.

28. Conservation Biology   Working with people The philosophy of sustainable use strives to enable people to use natural resources in ways that will benefit them and maintain the ecosystem.   Reintroduction and species preservation programs

29. Conservation Biology  Bioremediation is the use of living organisms to detoxify polluted ecosystems –These lichens are concentrating mining wastes