1

2 Chapter 2 Principles of Ecology 2.1 Organisms and Their Relationships Ecology The study of the relationships between living organisms and their interactions with the environment

3 Ecologist at Work

4

5 Levels of OrganizationChapter 2 Principles of Ecology 2.1 Organisms and Their Relationships Levels of Organization Levels increase in complexity as the numbers and interactions between organisms increase. organism population biological community ecosystem biome biosphere

6 Organism: The most basic level of organization in an ecosystem. Chapter 2 Principles of Ecology 2.1 Organisms and Their Relationships Organism: The most basic level of organization in an ecosystem. Example: Wolf

7 Population : Organisms of one species that share the same geographic locationExample: Wolf Pack

8 Biological community: a group of interacting populations that live in the same geographic area at the same time Example: Wolf Pack and Caribou

9 Ecosystem: a community and all of the abiotic factors that affect itChapter 2 Principles of Ecology 2.1 Organisms and Their Relationships Ecosystem: a community and all of the abiotic factors that affect it

10 Abiotic Factors: Nonliving factors in an environmentOrganisms adapt to survive in the abiotic factors present in their natural environment Biotic Factors: Living factors in an environment

11 Examples of Biotic and Abiotic Factors

12 Biome: a large group of ecosystems that share the same climate and have similar types of communities.

13 A thin layer around EarthChapter 2 Principles of Ecology 2.1 Organisms and Their Relationships The Biosphere A thin layer around Earth Extends several kilometers above the Earth’s surface Extends several kilometers below the ocean’s surface

14 Biosphere

15 The Biosphere 2.1 Organisms and Their Relationships Chapter 2Principles of Ecology 2.1 Organisms and Their Relationships The Biosphere

16 Ecosystem InteractionsChapter 2 Principles of Ecology 2.1 Organisms and Their Relationships Ecosystem Interactions A habitat is an area where an organism lives. A niche is the role or position that an organism has in its environment.

17 Alaskan Wolf Habitat

18 Alaskan Wolf Niche Keeps caribou population healthy

19 Community InteractionsCompetition: when more than one organism uses resources at the same time Examples:

20 Predation: the act of one organism consuming another organism for foodPredators: hunters Prey: the hunted

21 Predator-Prey Relationship

22 Almost every species is food for another speciesPredators (hunters) and prey (the hunted) have (in most cases) existed together for years

23 Predators have evolved into efficient killing machines (talons, canines, claws)Prey have evolved very effective defenses (smell, hearing, camouflage) The predator population is closely linked to the prey population

24 Symbiotic RelationshipsChapter 2 Principles of Ecology 2.1 Organisms and Their Relationships Symbiotic Relationships Relationship that exists when two or more species live together Mutualism Commensalism Parasitism

25 Mutualism Two or more organisms that live closely together and benefit from each other Example: Lichens—a relationship between algae and fungi Algae provides food for the fungi, and the fungi provides habitat for the algae

26 Lichen

27 Commensalism One organism benefits from the relationship, the other is unaffected by it Example: anemone fish and sea anemones

28 Ex. Barnacles and a sea scallop

29 Parasitism One organism benefits at the expense of the otherEx. Sea lamprey and fish

30 Section 2.2 Energy Flow in an Ecosystem

31 Also called primary producersChapter 2 Principles of Ecology 2.2 Flow of Energy in an Ecosystem Energy in an Ecosystem Autotrophs Organisms that collect energy from sunlight or inorganic substances to produce food Also called primary producers A lynx is a heterotroph.

32 Examples of Autotrophs

33 Heterotrophs: organisms that gain energy from consuming other organismsAlso called consumers

34 Types of Heterotrophs:Herbivores: eat autotrophs (plants)

35 Carnivores: eat other heterotrophs (animals)

36 Omnivores: eat autotrophs and heterotrophs (plants and animals)

37 Detritivores eat fragments of dead matter in anChapter 2 Principles of Ecology 2.2 Flow of Energy in an Ecosystem ecosystem, and return nutrients to it. Detritivores eat fragments of dead matter in an Fungus

38 Trophic level: Each step in a food chain or food webChapter 2 Principles of Ecology 2.2 Flow of Energy in an Ecosystem Models of Energy Flow Food chains and food webs model the energy flow through an ecosystem. Trophic level: Each step in a food chain or food web

39 Food chain: model that shows how energy flows through an ecosystem.Chapter 2 Principles of Ecology 2.2 Flow of Energy in an Ecosystem Food Chains Food chain: model that shows how energy flows through an ecosystem.

40 Notice that the arrows point in the direction of the energy flow, NOT which organism eats which!The original source of energy is the sun Sun → Corn → Pheasant → Fox

41 There may be more than one level of consumer in a food chainEx. Grass → grasshopper → toad → snake → hawk Producer → primary consumer (herbivore)→ secondary consumer (carnivore) → tertiary consumer (omnivore)

42 Food web: model representing the many interconnected food chainsChapter 2 Principles of Ecology 2.2 Flow of Energy in an Ecosystem Food Webs Food web: model representing the many interconnected food chains

43 Food Web Consists of two or more interacting food chainsMost food chains are part of a food web

44 Chapter 2 Principles of Ecology

45 Chapter 2 Principles of Ecology 2.2 Flow of Energy in an Ecosystem Ecological Pyramids A diagram that can show the relative amounts of energy, biomass, or numbers of organisms at each trophic level in an ecosystem

46 Pyramid of Energy (Energy Chain)

47 The size of the boxes indicate the relative amount of energy availableThe lower levels limit the upper levels Available energy decreases as you move up the levels

48 Energy never “cycles,” it dissipates into the system (used for life processes and given off as heat and used for storage) Only 10% of the energy available at one trophic level can be used by the consumers at the next level

49 If the first level of the energy pyramid (the producers) provide 1,000J of energy, how much is available to the second trophic level? 100J

50 How much energy is available for the third level?10J The fourth? 1J

51 Pyramid of Biomass

52 Pyramid of Biomass The total amount of biological matter (tissue) in a community or population Notice it takes many producers to support one shark The lower levels limit the upper trophic levels

53 Pyramid of Numbers

54 Cycles in the BiosphereChapter 2 Principles of Ecology 2.3 Cycling of Matter Cycles in the Biosphere Energy is transformed into usable forms to support the functions of an ecosystem. The cycling of nutrients in the biosphere involves both matter in living organisms and physical processes.

55 Chapter 2 Principles of Ecology

56 Chapter 2 Principles of Ecology

57 Chapter 2 Principles of Ecology