Introduction to Ecology

1. Introduction to Ecology What is Ecology?

2. Interactions and Interdependence • Ecology – field of science that studies the interactions of organisms and between organisms and their environment • “eco-” “oikos” (Greek) “house” • “ology” “study of” • Ecology is the study of nature’s houses!

3. Interactions and Interdependence • The largest of these “houses” is the biosphere • Biosphere – combined portions of the planet in which all life exists, including land water and air • The biosphere is ~8 km above earth’s surface and ~11 km below ocean’s surface • INTERACTIONS within the biosphere create a web of INTERDEPENDENCE is created between organisms and their environment

4. Cell – basic unit of life Tissue – groups of similar cells Organs – groups of similar tissues Organ Systems – groups of organs with a similar function Organism – groups of organ systems that make up an individual Species – group of similar organisms that can breed with one another and produce fertile offspring Population – group of same species in the same area Community – group of different populations in the same area Ecosystem – all living and non-living things in the same area Biome – group of ecosystems with similar climates and communities Biosphere – all biomes put together Levels of Organization Non-Ecology Ecology

5. Organism (Giraffe) Population (Herd of Giraffes) Community (Giraffe, Zebra, Wildebeest, Trees, Grass) Biome (Southeast area of Africa outlined in yellow) Biosphere (Earth) Ecosystem (Living and Non-living)

6. Ecological Methods • Ecologists have three (3) basic approaches to conducting research: • Observing • Ex: Jane Goodall • Experimentation • Artificial environment in laboratory or within natural ecosystem • Modeling • Often used to study phenomena that occur over a long period of time (e.g. global warming)

7. Ecology Energy Flow

8. Producers • Sunlight is the MAIN source of energy for all life on Earth • Only plants, some algae, and certain bacteria can capture energy from the sun and convert it into a USABLE form of energy • Autotrophs – organisms that capture and convert the sun’s energy • Also called PRODUCERS!

9. Producers • Producers use a process known as photosynthesis • Light energy is used to convert carbon dioxide (CO2) and water (H2O) into oxygen (O2) and carbohydrates (C6H12O6) Carbon Dioxide+Water+SunlightCarbohydrates+Oxygen

10. Producers • Some autotrophs can produce food without light by using a process called chemosynthesis • Chemical energy is used to convert hydrogen sulfide (H2S), carbon dioxide (CO2), and water (H2O) into carbohydrates (C6H12O6) and sulfur compounds (H2SO4) • This usually occurs in remote locations (e.g. ocean floor and hot springs) • Bacteria are the most common autotrophs that use chemosynthesis

12. Photosynthesis “photo-” means “light” Uses light for energy Chemosynthesis “chemo-” means “chemicals” Uses chemicals for energy Producers

13. Consumers • Many organisms cannot use sunlight as food • Animals, fungi, some bacteria • These organisms must consume other organisms to obtain energy • These organisms are called heterotrophs • Also called CONSUMERS!

14. Consumers • Five (5) main types of heterotrophs: • Herbivore – consumes only plants • Carnivore – consumes only animals • Some scavengers are considered carnivores • Omnivore – consumes plants and animals • Detritivores – consumes decaying and rotting material (such as rotting leaves, etc.) • Some scavengers are considered detritivores • Decomposers – breaks down organic (living) material • Finishes the job that scavengers and detritivores start

15. Feeding Relationships • Energy flows through an ecosystem in one direction Sun/ Inorganic Compounds Autotrophs Heterotrophs

16. Feeding Relationships • Food Chain – series of steps in which organisms transfer energy by eating and being eaten • Shows one-way flow of energy in an ecosystem

17. Feeding Relationships • Most feeding relationships are more complicated than a food chain • Food Web – network of complex interactions and feeding relationships in an ecosystem

18. Marine Food Web Terrestrial Food Web

19. Feeding Relationships • Trophic Levels – steps in the food chain/web • Producers – 1st trophic level • Consumers – 2nd, 3rd, or higher trophic levels • Each consumer depends on the previous trophic level

20. 5th Trophic Level 5th Trophic Level 4th Trophic Level 4th Trophic Level 3rd Trophic Level 3rd Trophic Level 2nd Trophic Level 2nd Trophic Level 1st Trophic Level 1st Trophic Level

21. Ecological Pyramids • Ecological Pyramid – diagram that shows the relative amount of energy or matter contained within each trophic level of a food chain/web • 3 Types • Energy Pyramid – shows the relative amount of energy available at each trophic level • Biomass Pyramid – shows the amount of living organic material at each trophic level • Pyramid of Numbers – shows the relative number of individual organisms at each trophic level

22. Energy Pyramid • Only part of the energy that is stored at one trohpic level can be passed to the next trophic level • 10% of the energy at one level is transferred to the next • Why isn’t ALL the energy transferred to the next level? • The other 90% is used by the organism at the previous level

23. Energy Pyramid Light or Chemical Energy

24. Biomass Pyramid • Biomass – total amount of living tissue within a given trophic level • Usually expressed in terms of grams of organic matter per unit area • Biomass pyramid represents the amount of potential food available for each trophic level in an ecosystem

25. Biomass Pyramid 10 % 10 % 10 % 10 %

26. Pyramid of Numbers • Based on the actual number of individuals at each trophic level • Does not always resemble the shape of a pyramid • Ex: tree may be at bottom of “pyramid”

27. Pyramid of Numbers

28. Pyramid of Numbers