Download 1. CHAPTER 14 INTRO

autotrophs
Organisms: Energy Sources
 Producers: plants and bacteria
 derive energy from inorganic sources
 phototrophs & chemotrophs
heterotrophs
 Consumers: grazers, carnivores,etc.
 derive energy from living organisms (organic
sources)
 Decomposers: fungi, scavengers, etc.
 derive energy from dead organic matter (organic
sources)
Energy Flow
The 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
TROPHIC LEVELS
Radiant energy
of sunlight
Trees, shrubs,
grasses and ferns
Producers
1st trophic level
Phytoplankton, algae
Herbivores
Plant-eating
insects, small
birds, possums
Primary Consumers
2nd trophic level
Zooplankton, whelks
Carnivores
Antechinus, owls
Secondary
Consumers
3rd trophic level
Starfish, small fish
Snakes, eagles
Tertiary Consumers
4th trophic level
Large fish, sharks
Open forest
system
Temperate coastal
sea ecosystem
Categories of Consumers
 primary consumers: (=herbivores) feed directly on
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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).
What is the polar bear doing?
Fig 2-11b
Major components of aquatic ecosystems.
Fig. 4–11
Major components of terrestrial ecosystems.
Fig. 4–12
The Importance of Decomposers
Fig. 4–16
Factors Limiting Populations
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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.
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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.
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Ex: too much fertilizer will kill plants.