102 CHAPTER 5 How Ecosystems WorkDetritus feeders work together with microbial decompos-
ers to destroy dead organisms and waste products.
Bacteria and fungi are important examples of
decomposers, organisms that break down dead organ-
isms and waste products (Figure 5.4d). Decomposers
release simple inorganic molecules, such as carbon
dioxide and mineral salts, which producers can then
reuse.
Producers provide both food and oxygen for the rest
of the community. Consumers play an important role by
maintaining a balance between producers and decom-
posers. Detritus feeders and decomposers are necessary
for the long-term survival of any ecosystem because, with-
out them, dead organisms and waste products would ac-
cumulate indefinitely.consumers, or herbivores. Grasshoppers, deer, moose, and
rabbits are examples of primary consumers (Figure 5.4a).
Secondary consumers eat primary consumers, whereas tertiary
consumers eat secondary consumers. Both secondary and
tertiary consumers are carnivores that eat other animals.
Lions, spiders, and lizards are examples of carnivores
( Figure 5.4b). Other consumers, called omnivores, eat a va-
riety of organisms. Bears, pigs, and humans are examples
of omnivores.
Some consumers, called detritus feeders, consume
detritus, organic matter that includes animal carcasses,
leaf litter, and feces (Figure 5.4c). Detritus feeders, such
as snails, crabs, clams, and worms, are abundant in aquatic
environments. Earthworms, termites, beetles, snails, and
millipedes are terrestrial (land-dwelling) detritus feeders.
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b. A European bee eater (a tertiary consumer) snatches its meal,
a dragonfly (a secondary consumer). Both the bee eater and the
dragonfly are carnivores.a. The moose is
an herbivore, or a
primary consumer.
The chemical energy
stored in grasses
transfers to the moose
cow as it eats.d. The mushrooms growing on a dead tree are reproductive
structures; the invisible branching, threadlike body of the
mushroom grows in the tree trunk, decomposing dead organic
material.c. A Sally Lightfoot crab forages for detritus on volcanic rock in
the Galápagos Islands.