Lec 1(2) (1).ppt Environment introduction
- 2. Ecology • The study of the interactions between organisms and the living & nonliving parts of the environment Humans have always needed to understand ecology in order to survive
- 3. Today’s Environment Early human cultures were Hunter-Gatherers (relied on practical knowledge about the environment) Current human cultures need to understand the critical impact they have on the Earth (depletion of natural resources)
- 4. Human Population • The human population has steadily increased • There was a rapid increase after the industrial revolution (better hygiene, transportation, vaccinations, food harvest and shipment) • According to the U.N., the world population can be 12.5 billion by 2050
- 5. Effects of the Human Population • As the human population continues to grow, we increase the demand for Earth’s resources • Since all life is interconnected, human destruction of habitats (natural environment) and contamination from our pollution will have an impact on all living organisms
- 6. The Sixth Mass Extinction • According to fossil records, there have been 5 mass extinctions in the past • Currently, we are experiencing the 6th mass extinction (Extinction of animals, plants, and other organisms caused by human actions may go as far back as the late Pleistocene, over 12,000 years ago) • The overpopulation of humans is causing species to become extinct on daily basis
- 7. Ozone Depletion • Ozone layer protects living organisms from harmful UV radiation • Chlorofluorocarbons (CFC’s) chemically react with the ozone and destroy it
- 8. Climatic Changes • Greenhouse Effect: carbon dioxide and water vapor in the atmosphere redirect Earth’s reflected heat and keep the planet warm enough to sustain life • Human activities are continually increasing the amount of CO2 in the atmosphere
- 9. Global Warming • As fossil fuels are burned, CO2 is released • More people + more fossil fuels being used = a warmer planet • More CO2 in the atmosphere results in more heat being redirected back at our planet
- 10. Impacts of Global Warming •The average global temperature will increase 3-8º F by 2100 •Polar ice caps are already melting faster than expected •Changes in rainfall and weather patterns will lead to famine, starvation, and disease
- 11. Levels of Organization in Ecology
- 12. The Biosphere • Where all life is found on Earth • Extends 8-10 km above Earth’s surface and below the ocean into the deepest parts • Most organisms are found within a few meters of the surface of the land or oceans
- 13. Ecosystems • Includes all of the organisms (biotic factors) and the nonliving components (abiotic factors) in a particular place • Example: a pond ecosystem
- 14. Community • All of the interacting organisms living in an area • Ecologists study how species interact and how these interactions influence the entire community
- 15. Population • All the members of a species that live in the same place at the same time
- 16. Organism • Refers to a living thing • Ecologists study the adaptations that an organism has that helps it overcome the challenges in its environment
- 17. Key Theme • All life is interconnected! No organism is isolated! • Survival of a species (including humans) depends on interdependence • Example: humans could not survive without the nitrogen-fixing bacteria that live in the roots of legume plants
- 18. Disturbances in Ecosystems • One change in an ecosystem will affect many species • Example: logging a forest (results in less habitat for all animal species, increases runoff that leads to water pollution, less trees using the atmospheric CO2 , etc.)
- 19. Ecology of Organisms • Where organism’s lives depends on its evolutionary history, its tolerances and requirements, the history and conditions of its habitat, and many other factors
- 20. Biotic and Abiotic Factors • Biotic factors- includes the living components • Abiotic factors- nonliving components such as the physical and chemical characteristics of the environment
- 21. The Changing Environment • Abiotic factors are always changing (daily temperature changes, rainfall, seasons, etc) • Organisms are adapted to function within a specific range of temperatures • An organism cannot survive in areas where the temperatures are beyond its tolerance
- 22. Acclimation An organism’s adjustment to an abiotic factor Occurs within the lifetime of an individual (NOT an adaptation!) Example: goldfish raised at higher temps. will have a different tolerance curve
- 23. Control of Internal Conditions • Conformers: organisms that don’t regulate their internal conditions (example: desert lizards) • Regulators: organisms that use energy to control some of their internal conditions (example: mammals)
- 24. Escape from Unsuitable Conditions • Dormancy: a state of reduced activity during periods of unfavorable environmental conditions • Examples: hibernation and estivation
- 25. Migration • Moving to a more favorable habitat to escape unfavorable conditions • Example: bird migration
- 26. Resources • Refers to the energy and materials a species needs to survive • Includes food, nesting sites, territory, water, sunlight, optimal temperature range
- 27. The Niche • A species way of life or its role in the environment • Includes the range of conditions the species can tolerate, how it obtains its resources, the number of offspring, time of reproduction, etc.
- 28. Fundamental vs. Realized Niche • Fundamental niche- the entire range of conditions and resources that a species could potentially utilize (very broad) • Realized niche- includes what is actually used by a species
- 29. Niche Differences • Generalists: species with broad niches (can tolerate a range of conditions and use a variety of resources) example: moths • Specialists: species with narrow niches (feed on a limited type of resources) example: butterflies