Ecology is:

1. Ecology is: The study of the interactions among organisms and their interrelationships with the physical environment. No organism exists as an entity, separate and distinct from its environment

2. 1. Components Components of the ecosystem involve interacting abiotic factors and biotic factors. 11

3. *a. Abiotic Factors The abiotic environment includes physical and chemical factors which affect the ability of organisms to live and reproduce. Light Intensity Temperature 12

4. The Abiotic Factors include: - Intensity of light - Range of temperatures - Amount of moisture - Type of substratum - Availability of inorganic substances such as minerals - Supply of gases such as O2, CO2, N2. - pH

5. Each of these factors varies in the environment and, as such, may act as a limiting factor, determining the types of organisms which may exist in that environment. Examples include: - A low annual temperature common to the northern latitudes determines determines in part what species of plants can exist in that area. - The amount of oxygen dissolved in a body of water will help determine which species of fish will exist there. - The salt-laden air and water of coastal areas limit what species can exist in those regions.

6. B. Biotic Factors Biotic Factors are all the living things that directly, or indirectly affect the environment. Thus, the organisms, their presence, parts, interaction, and wastes, all act as biotic factors. Biotic Factors interact in many ways such as in nutritional relationships and symbolic relationships.

7. Part I: Ecological Organization

8. A. Population A population is all the members of a species inhabiting a given location

9. B. Community All the interacting populations in a given area represent a community

10. C. Ecosystem An ecosystem is the living community and the physical environment functioning together as an interdependent and relatively stable system.

11. D. Biosphere The biosphere is the portion of the earth in which life exists. It is composed of numerous complex ecosystems.

12. Biomes A major regional or global biotic community, such as a grassland or desert, characterized chiefly by the dominant forms of plant life and the prevailing climate. Biomes may be terrestrial or aquatic. The temperate deciduous forest of the northeastern United States is a terrestrial biome. The ocean is an aquatic biome.

13. a. Terrestrial Biomes The major plant and animal associations on land are determined by the major climate zones of the world, modified by local land and water conditions. Climates will vary as to temperature, solar radiation, and precipitation. The presence or absence of water is a major limiting factor for terrestrial biomes.

14. 1) Characteristics Land biomes are characterized and sometimes named by the climax vegetation in the region. The major land biomes, and their characteristics, flora, and fauna are listed on the next pages.

15. Tundra: Characteristics: permanently frozen subsoil Climax Flora: Lichens, mosses, grasses Climax Fauns: Caribou, Snowy Owl

16. Characteristics: long, severe winters; summers with thawing subsoil. Climax Flora: conifers Climax Fauna: moose & black bear Taiga:

17. Temperate-Deciduous Forest: Characteristics: moderate precipitation; cold winters, warm summers Climax Flora: trees that shed leaves (deciduous trees) Climax Fauna: gray squirrel, fox & deer

18. Tropical Forest: Characteristics: heavy rainfall; constant warmth Climax Flora: many species of broad-leafed plants Climax Fauna: snake, monkey, leopard

19. Grassland: Characteristics: considerable variability in rainfall and temperature; strong prevailing winds Climax Flora: grasses Climax Fauna: pronghorn antelope, prairie dog & bison

20. Desert: Characteristics:sparse rainfall;extreme daily temperature fluctuations Climax Flora:drought-resistant shrubs and succulent plants Climax Fauna: kangaroo rat & lizard

21. 2) Geographic Factors Climatic conditions change with latitude and altitude.

22. Altitude; Latitude

23. b. Aquatic Biomes The largest part of the biosphere (the earth) is made up of aquatic biomes. It was here that life first arose, and here it evolved for almost three billion years, before plants and animals moved onto land. There are two main types of Aquatic Biomes: Freshwater and Marine. Freshwater biomes usually have a salt concentration of less than 1%, whereas Marine biomes have a salt concentration that averages 3%.

24. b2. Freshwater Biome Freshwater Aquatic Biomes have close ties to their surrounding terrestrial biomes. Runoff of water from land creates streams and rivers, and where runoff in trapped, ponds and lakes are formed. Also, the characteristics of a freshwater biome are influenced by the pattern and speed of water flow, as well as the climate to which the biome is exposed.

25. b3) Marine Aquatic Biomes Marine Aquatic Biomes are found in the Earth’s oceans, covering nearly 75% of the Earth’s surface. Most of the planet’s rainfall is from the evaporation of the Earth’s oceans, and the temperatures of the oceans strongly effect the world’s climate and wind patterns. Marine Algae are a major source of oxygen for the world, as well as consuming huge amounts of carbon dioxide from the atmosphere.

26. Part II: Ecosystems

27. Ecosystems are: The ecosystem is the structural and functional unit studied in ecology.

28. A. Ecosystem Structure and Function An ecosystem involves interactions between abiotic and biotic factors. An ecosystem is a self-sustaining unit if the following requirements are met: - A constant source of energy and a living system capable of incorporating this energy into organic compounds. - A cycling of materials between organisms and their environment.

29. 1) Nutritional Relationships Nutritional Relationships involve the transfer of nutrients from one organism to another within an ecosystem.

30. a) Autotrophs These organisms can synthesize their own food from inorganic compounds and an unable energy source.

31. b) Heterotrophs These organisms cannot synthesize their own food and are dependent upon other organisms for food. On the basis of this dependency, organisms are classified as either saprophytes, herbivores, carnivores, or omnivores.

32. (1) Saprophytes - include those heterotrophic plants, fungi, and bacteria which live on dead matter.

33. (2) Herbivores - are those animals which consume plants

34. (3) Carnivores - are those animals which consume other animals. These include: - PREDATORS ---- animals which kill and consume their prey. - SCAVENGERS ---- animals which feed on other animals which they did not kill.

35. (4) Omnivores - are those animals which consume both plants and animals.

36. 2) Symbiotic Relationships Different organisms may live together in a close association. This living together in a close association is known as symbiosis. Symbiosis relationships may or may not be beneficial to the organisms involved. Symbiotic Relationships may include: Nutritional. Reproductive, and protective relationships.

37. These types of Symbiosis include: a) Commensalism - In this relationship one organism is benefited and the other is not adversely affected. Example: Barnacles & Whales In this relationship both organisms benefit from this association. Example: Nitrogen-fixing bacteria within the nodules of legumes & certain protozoa within termites. In this relationship, the parasite benefits at the expense of the host. Example: Tapeworm and heart worm in dogs. b) Mutualism - c) Parasitism -

38. 2) Energy Flow Relationships If an ecosystem is to be self-sustaining it must contain a flow of energy

39. a. Energy Flow Those life activities which are characteristics of living organisms require the expenditure of energy The pathways of energy through living components of an ecosystem are represented by food chains and food webs.

40. b. Food Chain Green plants convert radiant energy from the sun into chemical energy (food). A food chain involves the transfer of energy from green plants through a series of organisms with repeated stages of eating and being eaten.

41. C. Food Web In a natural community, the flow of energy and materials is much more complicated than is illustrated by any one food chain. Since practically all organisms may be consumed by more than one species, many interactions occur among the food chains of any community. These interactions are described as a food web. Interactions in a food web involve: 1) Producers 2) Consumers 3) Decomposers

42. A Simple Food Web coyotes Rats spiders rabbits snakes hawks Grasses shrubs lice frogs Seed-eating birds insects Deer

43. Producers The energy from a community is derived from the organic compounds synthesized by green plants. Autotrophs are therefore considered the producers.

44. Consumers Organisms that feed directly upon green plants are primary consumers or herbivores. Secondary consumers, or carnivores, feed upon other consumers. Omnivores may be either primary or secondary consumers.

45. Decomposers Organic wastes and dead organisms are eventually broken down to simpler substances by decomposers, such as the bacteria of decay. Through this action, chemical substances are returned to the environment where they can be used by other living organisms.

46. D. Pyramid of Energy Energy flows through ecosystems from producers to various levels of consumers. Each time an organism eats one another, not all of the energy is transferred. Only about 10% of energy of a producer is transferred to the consumer who eats it. Therefore, there is a progressive loss of energy at each level of the food chain. We can represent each amount of energy at each level as a part of a pyramid.

47. d.Pyramid of Energy

48. E. Biomass Pyramid It is possible to estimate the mass of all the organisms living in a given area or ecosystem. The estimation is known as the bio mass. If the mass of the producers and each type of consumer is recorded, a pyramid can be constructed showing the bio mass of the producers is far greater then the bio mass of the consumers.

49. e. Biomass Pyramid

50. 3. Material Cycles In a self-sustaining ecosystem, material must be cycled among the organisms and the abiotic environment. Therefore, the same materials can be reused.