1. Introduction to Ecology
Chapter 19

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 could be between 7.8 – 12.5 billion by 2050

6. 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 and contamination from our pollution will have an impact on all living organisms

7. 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!
The overpopulation of humans is causing species to become extinct on a daily basis

8. Ozone Depletion
Ozone layer protects living organisms from harmful UV radiation
Chlorofluorocarbons (CFC’s) chemically react with the ozone and destroy it

9. Ozone Depletion
Although the depletion occurs over most of the planet, it is most concentrated over Antarctica
The ozone hole led to the ban of CFC’s in 1992
Currently, 1% of UV rays reaches
Earths surface and causes ½ million
cases of skin cancer each year

10. 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

11. 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

12. 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

13. Levels of Organization in Ecology

14. 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

15. Ecosystems
Includes all of the organisms (biotic factors) and the nonliving components (abiotic factors) in a particular place
Example: a pond ecosystem

16. Community All of the interacting organisms living in an area
Ecologists study how species interact and how these interactions influence the entire community

17. Population
All the members of a species that live in the same place at the same time

18. Organism Refers to a living thing
Ecologists study the adaptations that an organism has that helps it overcome the challenges in its environment

19. 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

20. 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.)

21. Ecological Models Models are often used when studying ecosystems
Can be graphs, diagrams, or mathematical equations

22. Ecology of Organisms
Where an organism lives depends on its evolutionary history, its tolerances and requirements, the history and conditions of its habitat, and many other factors

23. Biotic and Abiotic Factors
Biotic factors- includes the living and once living components
Abiotic factors- nonliving components such as the physical and chemical characteristics of the environment

24. 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

25. 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

26. 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)

27. Escape from Unsuitable Conditions
Dormancy: a state of reduced activity during periods of unfavorable environmental conditions
Examples: hibernation and estivation

28. Migration
Moving to a more favorable habitat to escape unfavorable conditions
Example: bird migration

29. Resources
Refers to the energy and materials a species needs to survive
Includes food, nesting sites, territory, water, sunlight, optimal temperature range

30. 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.

31. 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

32. 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