Ecology Chapter 3.1 to 3.3

1. EcologyChapter 3.1 to 3.3

2. What is Ecology? • Ecology – the study of interactions among organisms and between organisms and their environment • Biosphere – the largest of the areas of the earth containing the portion of the planet that life exists, including land, water and air (atmosphere)

3. Levels of Organization Ranges in complexity from single individual to entire biosphere.

4. Levels of Organization • Individual – one organism • Population– group of individuals that belong to the same species and live in the same area • Species - a group of individuals so similar to one another that they can breed and produce fertile offspring. • Community–different populations that live together is a defined area • Ecosystem– all the organisms that live in a similar area along with the nonliving material • Biome– group of ecosystems (similar climate) • Biosphere– entire earth

5. Ecological Methods • Scientists use 3 basic methods to conduct ecological research. 1. Observing – qualitative and quantitative observations 2. Experimenting – used to test hypotheses, can set up artificial environments and manipulate conditions 3. Modeling – models are made to study events that have occurred over large time periods, or are large in scale

6. Interactions Among Organisms- Energy Flow • Sunlight is the main energy source for life on Earth • Producers – autotrophs (make their own energy using the sun) • Photosynthesis – using light to produce energy / food • Chemosynthesis – using inorganic molecules to produce energy / food

7. Energy Flow Photosynthesis Chemosynthesis

8. Energy Flow • Consumers – heterotrophs (cannot make their own energy) • Herbivores – consume plants • Carnivores - consume meat • Omnivores – consume both • Detritivores–feed on dead or decaying matter • earthworms, mites, crabs, snails • Decomposers – break down organic matter • bacteria & fungus

9. Energy Transfer / Feeding Relationships • Energy flows in one direction • Food Chain- series of steps where energy is transferred by eating and being eaten • Trophic Levels – each step in a food chain • Food Web –links all food chains in ecosystem together

10. Food Chain vs. Food Web

11. Ecological Pyramids • Diagram that shows relative amounts of energy or matter contained within each trophic level in a food chain or food web for an ecosystem • Energy Pyramid– energy available at each trophic level - 10% rule 2. Biomass Pyramid– amount of living tissue/potential food available in each level 3. Pyramid of Numbers- number of individual organisms

12. Examples of Pyramids

13. Recycling in the Biosphere • Water Cycle • Evaporation, precipitation, condensation, transpiration, run-off, ground water

14. Nutrient Cycle • Carbon Cycle – carbon fixation, CO2 • Photosynthesis, respiration • Fossil fuels • Human Activities • Mining, cutting forests, burning fossil fuels

15. Biogeochemical Cycles • Nitrogen cycle – nitrogen fixation (bacteria), denitrification

16. Biogeochemical Cycles • Phosphorus Cycle • Does not enter atmosphere. • In land, rocks, soil and ocean sediment as inorganic phosphate. • Will dissolve in water.

17. Nutrient Limitation • Primary Productivity – rate of production of organic matter by producers • Amount of available nutrients. • Limiting Nutrients – nutrient that limits productivity when scarce. • Aquatic ecosystems – large input of limiting nutrient can cause an increase of algae or producers = algal bloom

18. Chapter 4.2 What shapes an ecosystem?

19. Biotic Factors • Biological influences on organisms within an ecosystem • Include all living organisms. • Cast of characters that an organism might interact with • Bullfrog: • Plants and algae as a tadpole • Herons that eat adult bullfrogs • Other species that compete with frog for space and food.

20. AbioticFactors • Physical or non-living factors that shape an ecosystem • Climate: • Temperature, precipitation, humidity. • Wind, nutrients availability, soil type, sunlight • Biotic and Abiotic factors together determine the survival and growth of an organism and productivity of an ecosystem

21. Niche • An organisms habitat is its address, its niche is its occupation. • Full range of physical and biological conditions in which it lives and the way the organism uses these conditions. • Type of food it eats, how it obtains food, what other species use the organism as food.

22. Community Interactions • Competition- when organisms of same or different species attempt to use an ecological resource in the same place and at the same time. • Resource- necessity of life • Competitive Exclusion Principal- No two species can occupy the same niche in the same habitat at the same time. • Losing organism will fail to survive.

23. Community Interactions • Predation- One organism captures and feeds on another organism. • Symbiosis- “living together” • Mutualism- both benefit • Flowers and insects • Commensalism- one benefits, other is neither helped nor harmed. • Barnacles on marine animals • Parasitism- one organism lives on or inside another and harms it. • Tapeworms, fleas, ticks, lice

24. Label each

25. Ecological Succession • Predictable changes that occur in a community over time. • Ecosystems are constantly changing in response to natural and human disturbances. • As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further change.

26. Ecological Succession • Primary Succession -occurs on surfaces where no soil exists • Volcanic eruptions, bare rock • Pioneer species- first species to populate • Often lichens (fungus and algae) • When they die they add organic material to become soil. • Secondary succession – a disturbance changes an existing community without removing soil. • Land clearing and farming • Wildfires

27. Chapter 5.1 to 5.2: Populations

28. Three important characteristics of a population • 1. Geographic Distribution/Range • Area inhabited by a population • Varies in size- Microscopic to miles • 2. Population Density • Number of individuals per unit area. • Can again vary greatly • 3. Population Growth Rate • A. Number of Births • B. Number of Deaths • C. Number of individuals who have entered/leave population = immigration and emigration

29. Types of Population Growth • Exponential Growth- • Under ideal conditions with unlimited resources. • Will start out slow and then approaches an infinitely large size - J curve • Reproduce at a constant rate - Not in natural populations! • Logistic Growth • Populations growth will slow or stop after a period of exponential growth • As resources become less available, the growth of a population slows or stops - S curve • Reached carryingcapacity- number of individuals that a given environment can support

31. Limits to Growth • Limiting factors cause population growth to decrease. • Density Dependent- only become limiting when a population reaches a certain level (TOO LARGE) • Competition • Predation • Parasitism • Disease • Density Independent- affects populations in same way regardless of size • Unusual weather, natural disasters, seasonal cycles, human activities

32. Chapter 6.2 to 6.4:Humans in the Biosphere

33. Classifying Resources • Renewable resources- can regenerate or can be replenished by biochemical cycles • Can be living or nonliving • Nonrenewable resource- cannot be replenished by natural process. • Fossil fuels: coal, oil, natural gas. • Classification depends on context • EX: Trees • Single vs. entire population • Sustainable development • Using natural resources without depleting them.

34. Different types of Resources • Land Resources • Soil erosion- wearing away of soil by wind and water • Desertification-turning once productive areas into deserts. • Forest Resources • Deforestation- loss of forests • Fishery Resources • Overfishing • Aquaculture- raising aquatic animals for human consumption • Air Resources • Smog, pollutant • Freshwater Resources • Pollution

35. Biodiversity: Greatest Natural Resource • Sum total of all the genetically based variety of all organisms in the biosphere • Ecosystem Diversity • Habitats, communities, ecological processed • Species Diversity • Number of different species in the biosphere • Genetic Diversity • Sum total of all the genetic information carried by all organisms living on earth today.

36. Threats to Biodiversity • Extinction- species disappears • Endangered species- population size declining • 1. Habitat Alteration • Habitat fragmentation- development splits ecosystems into pieces • 2. Demand for wildlife products • 3. Pollution • Biological Magnification- concentration of harmful substances increases at higher trophic levels • 4. Introduced species • Invasive species- reproduce rapidly because of lack of predators • Conservation efforts are in place to manage natural resources.

37. Biological Magnification

38. Charting the course for the future • Researchers are gathering data to study the effects of human activities on the biosphere. • Ozone depletion. • Ozone layer- 20-50 kilometers above earth surface. Absorbs UV light before it reaches earths surface. • Global climate change • Global warming- increase in average temperature of biosphere.