The Nature of Ecology

How to make a food web.1. Start with one producer on BOTTOM and draw arrows up

to the things that eat them (their predators). (** Hint: a producer is something that photosynthesizes, it gets its energy from the sun.)

2. Fill in all the predators that eat that producer (these are primary consumers).

3. If there are other things those predators eat fill in those organisms (one at a time). These are other producers, other primary consumers or even sometimes secondary consumers.

4. Continue filling in each organism’s predators and prey placed at the correct trophic level (with arrows going from prey to predator).

5. Primary consumers eat producers. Secondary consumers eat primary consumers. Tertiary consumers eat secondary consumers. (some organisms will be at more than one level). If the hawk ate grass and rabbits, it would be both a primary and a secondary consumer and have arrows from both rabbit and grass.

Eagle tertiary consumer

Snake Hawk secondary consumer

Rabbit primary consumer

grass producer

The Nature of Ecology

Ecology- the study of how organisms interact with their environment

Organisms- any life form

Species- groups of organisms that share similar DNA; look similar, have similar behavior, can produce viable offspring.

Populations

Population- all of the organisms within a species that interact in a specific area and at a specific time

Communities, Ecosystems & The Biosphere Habitat- the place where a population or organism lives

Community- all of the organisms that occupy a specific area; also called biological community

Ecosystem- a community of different species and their interaction with each other and abiotic factors in environment

Ecosystem Concepts and Components

Biomes-areas with a consistent climate and with similar organisms

Aquatic life zones- marine and freshwater portions of the biosphere

Fig. 4-9 p. 70

Community Structure and Species Diversity

Fig. 8-2 p. 144

Fig. 8-2 p. 144

Biodiversity dependent on latitude

Fig. 8-3 p. 145

Ecosystem Boundaries: Ecotones

Ecotone- transitional zones between ecosystems where there are a mixture of species not found together in adjacent ecosystems

Fig. 4-10 p. 71

Principles of Ecological Factors Abiotic Factors- all of the nonliving parts in an ecosystem

Biotic Factors-all of the living factors in an ecosystem

Range of Tolerance- any variation in the physical or chemical environment that an organism can withstand before it is killed/harmed

Regulating Population Growth

Limiting Factors- a distinguishing chemical or physical factor that regulates the population growth of a species; more specific than any other factor

Niche- an organisms functional role within an ecosystem; everything that affects the survival and reproduction

Figure 4-13 Page 73

Terrestrial Ecosystems Aquatic Life Zones

• Sunlight• Temperature• Precipitation• Wind• Latitude• Altitude• Fire frequency• Soil

• Light penetration• Water currents• Dissolved nutrient concentrations (especially N and P)

• Suspended solids• Salinity

Abiotic Factors That Impact Populations

The Biotic Components of Ecosystems

Fig. 4-16 p. 75

Producers (autotrophs)

Consumers (heterotrophs)

Decomposers

Fig. 4-18 p. 77; Refer to Fig. 4-19 p. 78

Food Chains

Food Webs

• Only 10% of the energy producers make gets transferred to the primary consumer.

• The secondary consumer only gets 1%.

• The tertiary level gets 0.1%.

Native (indigenous) - naturally evolved to live in the area Western Red Cedar, Douglas Fir, Milkvetch, black squirrel

Native Species

Species naturally evolved to live in the area. Ex. douglas fir, western red cedar, milkvetch, black squirrel

Non-native (invasive species)Species introduced by humans, by mistake or intentionally. Also called exotic species.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Kudzu - aka: foot a night vine, mile a minute vine, or the vine that ate the south! Ironically introduced for soil conservation

purposes! $500 million per year in lost crops and

control costs

Special Roles of Some Species

Removal of keystone species will cause collapse of ecosystem

Special Roles of Some Species

Keystone Species

Pollinators Top Predators

Special Role of Some SpeciesIndicator species - ecosystem smoke alarms - abundance of population indicator of overall health and viability of ecosystem

Species Interactions: Competition

Interspecific competition- competition between two or more species

As a result of competition, the two species evolve to gain separate, more specialized niches (co-evolution)

Species Interactions

Mutualism - benefits both species

Ex. pollination

Commensalism - benefits one species, but has little effect on the other

Ex. Fern living in the shade of a tree

Species Interactions: Parasitism

Parasite - living on or in another species (host)

Important ecological role of parasites- increase biodiversity by keeping species that may eliminate other species in check