Biology Now, 2e

Plants

Amoebas,

others Animals Fungi

Zygomycetes (molds)

Ascomycetes (sac fungi)

Basidiomycetes (club fungi)

Fungi digest organic material outside

the body and absorb the molecules

released as breakdown products.

Fungi play several roles in

terrestrial ecosystems. Many are

decomposers, acting as garbage

processors and recyclers by

speeding the return of the

nutrients in dead and dying

organisms to the ecosystem.

Fungi are similar to animals in

that they store surplus food

energy in the form of glycogen.

Like some animals, such as

insects and lobsters, fungi

produce a tough material called

chitin that strengthens and

protects the body. Unlike

animals, fungal cells have a

protective cell wall that wraps

around the plasma membrane

and encases the cells.

Animals are

multicellular ingestive

heterotrophs,

obtaining energy and

carbon by ingesting

food. All animals are

consumers, and

some are important

decomposers in the

ecosystems they

inhabit.

Animal cells differ from those of

plants and fungi in that they lack

cell walls. Instead, many cells in

the animal body are enveloped

in, or attached to, a felt-like layer

known as the extracellular

matrix. An important evolutionary

innovation of animals is the

development of true tissues.

Most animals have two or three

main tissue layers that give rise

to a structurally complex body.

The sponges are the most

ancient animal lineage.

Cnidarians, a group that includes

jellyfish and corals, evolved next.

The remaining animal phyla fall

into two groups: the

protostomes and deuterostomes,

distinguished by different

patterns of embryonic

development. Protostomes

comprise more than 20 separate

subgroups, including mollusks

(such as snails), annelids

(segmented worms), and

arthropods (including spiders

and insects). Deuterostomes

include echinoderms (sea stars

and their relatives) and the

chordates. The chordates are a

large group that includes all

animals with backbones, such as

fish, birds, and humans.

Sponges Cnidarians Mollusks

Arthropods Echinoderms Chordates

Plantae Protista Animalia Fungi

Fungi

Animalia

Common ancestor

of animals and fungi

Q2: Are fungi more closely related to plants or to animals? Does the answer surprise you? Why or why not?

Q3: If you were to create an evolutionary tree in which amoebas were included within the kingdom of organisms to which

they were the most closely related (rather than with protists, where they are currently placed), where would you put them?