Organisms: Energy SourcesProducers: plants and bacteria

derive energy from inorganic sourcesphototrophs & chemotrophs

Consumers: grazers, carnivores,etc.derive energy from living organisms (organic

sources)

Decomposers: fungi, scavengers, etc.derive energy from dead organic matter (organic

sources)

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Energy FlowEnergy FlowThe ultimate source of energy in most ecosystems is the sun.

Producer – Photosynthesis – transform radiant energy into chemical energy

Ecosystem Structure: how the parts fit together

Trophic Structure: major feeding relationships between organisms

Producers (Autotrophs)

Those members of the community that manufacture organic compounds, such as glucose, from simple inorganic compounds, such as carbon dioxide, using an abiotic energy source, such as sunlight.

Through their energy transforming actions, they make chemical energy available as organic compounds for their own use and, directly or indirectly, other members of the living community.

Consumers (Heterotrophs)

Members of the community that must obtain their energy by eating other organisms or parts of them.

All animals are consumers

Consumers (Hetertrophs)

Consumer animals may be subdivided into the following groups; Herbivores – eat plants Carnivores – eat animals Omnivores – eat both plants and animals Detrivores – eat decomposing organic

matter (worms, beetles, crabs)

Energy Flow: Food Web

Trees, shrubs, grasses and ferns

Producers1st trophic level

Phytoplankton, algae

HerbivoresPlant-eating insects, small birds, possums

Primary Consumers2nd trophic level

Zooplankton, whelks

CarnivoresAntechinus, owls

Secondary Consumers3rd trophic level

Starfish, small fish

Snakes, eagles Tertiary Consumers4th trophic level

Large fish, sharks

Open forest system

Temperate coastal sea ecosystem

Radiant energy of sunlight

Categories of ConsumersCategories of Consumers

primary consumers: (=herbivores) feed directly on producers;

secondary consumers: (=carnivores) feed on primary consumers;

tertiary consumers: feed only on carnivores;omnivores: consumers that feed on both plants &

animals;scavengers: feed on dead organisms;decomposers (saprobes): consumers that complete

the breakdown & recycling of organic materials from the remains & wastes of other organisms;

detritivores: feed on detritus (partially decomposed organic matter, such as leaf litter & animal dung).

Fig 2-11b

What is the polar bear doing?

Major components of aquatic ecosystems.

Fig. 4–11

Major components of terrestrial ecosystems.

Fig. 4–12

The Importance of DecomposersThe Importance of Decomposers

Fig. 4–16

Factors Limiting Factors Limiting PopulationsPopulations Law of tolerance: the ability of species to tolerate changes

in their environment (physical or chemical factors). Pollution, global warming, habitat loss are some concerns associated with this.

Limiting factor: any environmental factor that reduces survival or reproduction within a population.

Ex: predation, temperature Limiting factor principle: too much or too little of any

abiotic factor can limit or prevent growth of a population, regardless if all other factors are near optimum range of tolerance.

Ex: too much fertilizer will kill plants.