Ecology

1. Ecology Ecosystems What they are?

2. Ecology: the study of relationships between living organisms and between organisms and their environments • Ecologist: The investigators who conduct ecological studies

3. Ecosystems a community and its abiotic environment • Understanding the interaction of the community and abiotic factors in an ecosystem can help us to see why particular human activities may be a problem for human survival. • Example: The loss of ozone in the stratosphere increases the quantity of UV radiation on the surface of the planet. In the same way that humans experience sunburn from too much sun exposure, so do plants. Excessive UV may damage or destroy plant protein and DNA, killing the plant.

4. Biotic communities: All the populations of different plants, animals and microbes occupying a given area. • Abiotic factors: All the factors of the physical environment: moisture, temperature, light, wind, pH, type of soil, salinity, etc.

5. Species: a group of organisms that can interbreed and produce fertile offspring • Populations: a group of organisms of the same species who live in the same area at the same time • Associations: A plant community with a definite composition, uniform habitat characteristics, and uniform plant growth.

6. Ecotone: transitional region that shares many of the species and characteristics of two ecosystems. It also includes unique conditions • Fig. An ecotone may create a unique habitat with specialized species not found in either of the ecosystems bordering it.

7. Landscapes: group of interacting ecosystems in a particular area. A barrier island, a saltwater bay, constitute a landscape Fig. Ecosystems are not isolated from one another. One ecosystem blends into the next through a transitional region, an ecotone, which contains many species common to the two adjacent systems.

8. Biomes: grouping of all the ecosystems of a similar type. I.e. tropical rain forests, grasslands, deserts, etc. • Biosphere: All the species on Earth, along with all the environments, make up one vast ecosystem, the Biosphere.

9. 2) The structure of Ecosystems Feeding relationships Trophic structure

10. Trophic structure Producers Consumers Detritivores and decomposers

11. Trophic structure • Producers: capture energy from the Sun or chemical reactions to convert carbon dioxide, an inorganic molecule into organic matter. • What is the difference between organic and inorganic molecules? • Producers are also known as autotrophs. What is an autotroph?

12. Trophic structure 2) Consumers: • Primary consumers: feed directly on producers (herbivores) • Secondary consumers: feed on primary consumers (carnivores) • Omnivores: feed on both plants and animals Consumers are also known as heterotrophs. What is an heterotroph?

13. The Structure of Ecosystems Feeding relationships among consumers Predator/prey relationships: any relationship in which one organism feeds on another. Parasites: plants or animals that become intimately associated with their “prey” and feed on it over an extended period of time without killing it. The organism that is fed upon is called host. Pathogens: bacteria and viruses that cause disease

14. Trophic structure 3) Detritivoresand saprotrophs: Organisms that feed on death plants or animals, feaces, etc. • Primary detritivores: organisms that feed directly on detritus • saprotrophs: secrete digestive enzymes that break down dead matter. I.e. bacteria and fungi. • Secondary detritivores: feed on primary detritus feeders. I.e. protozoans, mites, insects, and worms. • Are detritivoresautotrophs or heterotrophs?

15. Trophic categories

16. Activity: • Data based questions pg 176

17. 2) The structure of Ecosystems Feeding relationships Trophic relationships

18. Trophic relationships a. Food chains: feeding pathways • Food chains are a description of who eats whom. • Predator-prey and host-parasite describe specific feeding relationships. b. Food webs: complexes of feeding relationships. c. Trophic Levels or Feeding Levels • All producers belong to the first trophic level. • All herbivores (primary consumers) are on the second trophic level. • All primary carnivores (secondary consumers) are on the third trophic level. Reading: Rediscovering Biology pg 178

19. Trophic Relationships Food chain Food web

20. Activity: Construct a food web using the data table of pg 179

21. 2) The structure of Ecosystems Feeding relationships Energy flow in food chains

22. Energy flow in food chains • The initial source of energy for all ecosystems is sunlight. • Plants convert light energy into chemical energy • This energy is passed from consumer to consumer in a food chain, but most of it is lost from the community

23. Energy flow in food chains • The amount of energy converted to new biomass during a given time period by each trophic level in an ecological community can be represented by a pyramid of energy. • On average, 10% of the energy from one trophic level moves to the next trophic level. Secondary consumer 200 kJ m-2yr-1 Decomposers 16 000 kJ m-2yr-1 Primary consumer 2500 kJ m-2yr-1 Plankton 150,000 kJ m-2yr-1 An energy pyramid for an aquatic ecosystem (not to scale)

24. 2) Population growth What factors affect population growth?

25. Non feeding relationships • Mutually Supportive Relationships: mutualism. • Competitive Relationships • How are competitive relationships reduced?Habitat: placeNiche: role • What happens when competition is not reduced?Competitive exclusion principle

26. ABIOTIC FACTORS • Conditions: abiotic factors that vary in space and time, but are not used up or made unavailable to other species. i. e. temperature, wind, pH, salinity, fire • Resources: factors (biotic or abiotic) that are consumed by organisms. i.e. water, chemical nutrients, light, oxygen

27. Limiting Factors • Factors that limit growth, reproduction or even survival of a population. • Biotic or abiotic • Basic items include temperature, light, oxygen, carbon dioxide, and precipitation. • Only one limiting factor need be out of its optimum range to cause stress for an organism.

28. Population growth • The maximum size of a population that an environment can support is its carrying capacity. • A popultaion stops growing when it reaches its carrying capacity, then mortality equals natality, this is refferred to as the plateau phase of the S-curve Carrying capacity Plateau phase Limiting factors Transition phase

29. Population growth • Some populations can overshoot the carrying capacity of the environment. • The result is a “boom and burst” pattern

30. Limiting factors • Law of Limiting Factors - Quantities of any single factor above or below  optimum levels necessary for organism growth, reproduction, or survival will limit growth, reproduction, or survival. • Synergistic effects (synergism): two or more factors interacting in a way that causes an effect much greater than one would anticipate from the effects of each of the two acting separately.

31. Homework • Work on data based questions pp. 179, 181

32. Sources • http://www.harmonartillustrations.com/store/murals.php • http://emilyyyyyyyyyy.glogster.com/food-web-/ • http://drake.marin.k12.ca.us/stuwork/rockwater/PLANKTON/Food%20Chain.htm • http://cumuseum.colorado.edu/Research/Objects/sep04_lichens.html • http://www.colorado.edu/geography/courses/geog_1001_lab/ • http://apesnature.homestead.com/chapter2.html • http://www.exploringnature.org/db/detail.php?dbID=45&detID=2589 • http://gohealed.com/ • http://pediaview.com/openpedia/Detritivore • http://inkchromatography.wordpress.com/2011/11/26/feedback/