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Chapter 10 Biodiversity 3: Animals

• 10.1 Animals are consumers

• 10.2 Sponges and cnidarians

• 10.3 Three phyla of worms

• 10.4 Mollusks

• 10.5 Arthropods

• 10.6 Echinoderms

• 10.7 Vertebrates

• 10.8 Fishes

• 10.9 Amphibians and reptiles

• 10.10 Mammals

• 10.11 Humans evolved from primates

© 2017 Pearson Education, Inc.

10.1 Opening Questions: Are you an

animal?

• What traits do you share

with a jellyfish?


with an earthworm?

© 2017 Pearson Education, Inc. Chapter Table of Contents


with a chimpanzee?

10.1 All animals eat other organisms.

• Animals are

heterotrophs. They

obtain food from their

environment.

– Heterotrophs are also called consumers.

• In contrast,

autotrophs are

organisms that make

their own food (like

plants).

– Autotrophs are also called producers.


10.1 Animals are heterotrophs that evolved

from colonial protists.

• Biologists hypothesize

that the first animal

evolved around 600

million years ago.


This hypothetical organism may resemble

the colonies of protists that evolved into

the first animals.

Chapter Table of Contents

10.1 All animals share a set of common

features.


10.1 Today there are 9 major animal phyla.


Note that the vast majority of

animals are invertebrates,

animals without backbones.Chapter Table of Contents

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10.2 Opening Questions: Plant, animal, or

mineral?

• Take a good look at

the image.

• Is this a plant, an

animal, or a rock?

• Design a test that you

could perform that

would allow you to

make a definitive

conclusion.


10.2 Sponges and cnidarians are animals

that have unusual body features.

• Both groups are

mostly marine.

• Sponges lack

body symmetry

and tissues.

• Cnidarians are

radially

symmetrical; they

have tissues and

stinging cells.


10.2 Sponges have the longest

evolutionary history of all animals.

Characteristics of sponges:

1. Asymmetrical shape

2. Lack tissues

3. Sessile


In a sponge, the lack

of tissues means

that every cell must

be in contact with

the environment.


10.2 A gallery of sponges

Orange elephant ear sponge

Freshwater

sponge

Branching vase spongeChapter Table of Contents© 2017 Pearson Education, Inc.

10.2 Cnidarians include sea anemones,

hydras, corals, and jellies.

Characteristics of cnidarians:

1. Radial symmetry

2. Cells organized into tissues

3. Stinging cells

4. Two distinct body forms:


A stationary

polyp like this

sea anemone

A floating

medusa like

this jelly


10.2 A gallery of cnidarians

Gray hydra

Sea anemone

Sea wasp

Boulder brain coral

Chapter Table of Contents© 2017 Pearson Education, Inc.

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10.3 Opening Questions: True or false?

Explain your choice:

• True or false: Cnidarians, including jellies,

may predate dinosaurs by some 200 million

years.

• True or false: Most corals obtain the majority

of their energy from photosynthetic unicellular

algae that live within the coral’s tissue.

• True or false: Jellies can sting you even

after they are dead.


10.3 The animal kingdom includes three

phyla of worms with separate lineages.

• Flatworms,

annelids, and

roundworms

share similar body

shape, but vary

considerably.

• Each phylum has its

own evolutionary

heritage and

distinctive features.


10.3 Flatworms lack a digestive tract.

Characteristics of flatworms:

1. Bilateral symmetry

2. Gastrovascular cavity

3. No true body cavity

4. Eyespots

5. Sex organs

6. Some are parasites


A planarian


10.3 A gallery of flatworms

Marine fascia

flatworm

Fluke


Tapeworm

10.3 Annelids display a key evolutionary

adaptation: segmentation.

Characteristics of annelids:


2. Complete digestive tract

3. Closed circulatory system

4. Body cavity

5. Body segments


10.3 A gallery of annelids

Earthworm

Leech

PolychaetesChapter Table of Contents© 2017 Pearson Education, Inc.

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10.3 Roundworms, or nematodes, have

cylindrical bodies tapered at both ends.

Characteristics of roundworms:


2. Complete digestive tract

3. No body segments

Soil

nematode

Heartworm


• Thinking like a zoologist, describe an

observation you have made about an

animal?

• Generate a question and a hypothesis.

• How might you test your hypothesis?

10.4 Opening Questions: Can you think like

a zoologist?

Zoology (from the Greek zoon, animal + logos, to

study) is the study of animals including their growth,

development, function, distribution, and origin.

What types of questions does a zoologist ask?


10.4 Mollusks are a diverse phylum.

• Mollusks are a

phylum of soft-

bodied animals,

many of which are

protected by a hard

shell.

• Snails and slugs,

oysters and clams,

octopuses and squids

are all mollusks.


10.4 Mollusks all have a similar body plan

and many have a hard shell.

• Characteristics of mollusks:


2. Three main parts: muscular foot, visceral

mass, and mantle

3. Open circulatory system

4. External shell (most)

5. Gills (most)

6. Radula—file-like organ


Garden snail


10.4 A gallery of mollusks

Gastropods (snails and slugs)

Banana slug

Bivalves

(clams, mussels, and oysters)

Bay scallop

Cephalopods (squid and octopi)

European squid


10.5 Opening Questions: Heads and tails?

All animals, besides the cnidarians,

exhibit bilateral symmetry: they can

be split into roughly mirrored halves

by slicing down the midline.

However, the precise evolutionary

importance of bilateral symmetry is

still an area of active research.

• Identify at least one possible advantage of

having bilateral symmetry, including having

a head and a tail.

• Be prepared to explain your reasoning.


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10.5 The arthropods are by far the most

numerous and diverse phylum of animals.

• In terms of numbers of

individuals and species,

arthropods are the most

successful animal

phylum.

• Common groups of

arthropods include:

– Arachnids (e.g., spiders)

– Centipedes and millipedes

– Crustaceans (e.g.,

lobsters)

– Insects (e.g., butterflies)


10.5 Arthropods are tremendously diverse,

but share some key features.

Characteristics of arthropods:


2. Body segments:

− Head, thorax, and abdomen

3. Hard exoskeleton


An American

lobster


10.5 Arachnids are a group of eight-legged

arthropods.

• Arachnids include

spiders, scorpions,

ticks, and mites.

• Most are terrestrial

carnivores.


Yellow desert scorpion Wood tick Atlantic horseshoe crab

Tarantula


10.5 Millipedes and centipedes have

obviously segmented bodies.

• The two groups can be distinguished by

the number of legs on each body segment.

• All are land dwelling.


Centipede

(one pair of legs per segment)Millipede

(two pairs of legs per segment)


10.5 Crustaceans are common arthropods

in marine and freshwater habitats.

• Many of them (shrimp, lobster, crabs, etc.)

are valuable food crops.


Common rough woodlouse

Goosenecked barnacles

Brown crab


10.5 Insects, by far, outnumber all other

animals combined.

• Most have easily recognizable segments

(head, thorax, and abdomen), three pairs

of legs, and one pair of antennae.


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10.6 Opening Questions: True or false?

Explain your choice:

• True or false: There more kinds of insects

on Earth than any other kind of animal.

• True or false: The blood of lobsters is

blue.

• True or false: A flea can leap up to 38

times its body weight and at an

acceleration of around 100 g-force.


10.6 Echinoderms are a sister phylum to

the chordates.

• Echinoderms share

an evolutionary

branch with

chordates (which

include vertebrates).

• All species are marine.

• Echinoderms include:

sea stars, sea urchins,

sea cucumbers, and

sand dollars.


Characteristics of echinoderms:

1. Larval bilateral symmetry

− Often radially symmetrical as adults

2. Water vascular system and tube feet

3. Endoskeleton

4. Spiny surface

5. Tube feet

6. Mouth

7. Regeneration

10.6 Echinoderms are the phylum most

closely related to our own.


10.6 A gallery of echinoderms


Red sea

urchin

Bennett’s

feather star

Donkey dung sea cucumber

Brittle star


10.6 We share an evolutionary kinship with

echinoderms.

• Although an adult sea star looks nothing

like an adult human, our lineages share

some important similarities in embryo

development.


10.7 Opening Questions: Are you feeling

spineless?

Most of the chordates are also

vertebrates (have a backbone).

• What are all the similarities and

differences you can think of

among these vertebrate groups?• Fishes

• Amphibians

• Reptiles

• Mammals


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10.7 Vertebrates (animals with backbones)

belong to the chordate phylum.

• Common groups of

chordates include:

– Lancelets

– Tunicates

– Fishes

– Amphibians

– Reptiles

– Mammals


10.7 All chordates are recognized by four

features.

These four features are apparent in all

chordate embryos, but may not be clear

in the adult.


10.7 There are two chordate groups that are

classified as invertebrates.

Lancelets are small

animals that capture

food by filtering water

through their mouths.

Tunicates are sessile

and feed by filtering

seawater.


10.7 Most chordates are vertebrates.

• Vertebrates have an endoskeleton (an

internal skeleton) that includes a backbone

and a skull.


10.7 Novel features distinguish each of the

main groups of chordates.


10.8 Opening Questions: Mammal or fish?

At first glance, there are some similarities among

dolphins and sharks, even though a shark is a fish and

a dolphin is a mammal. This can be especially true in

grainy beach photos!• Why might the overall

body structure of the

shark and the dolphin

be so similar?


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10.8 The first vertebrates to evolve were

fishes.

• The first fish evolved

around 540 mya.

• The fish lineage was

the first to evolve

jaws.

• Modern fishes include

several lineages:

– Hagfish

– Lampreys

– Cartilaginous fishes

– Bony fishes© 2017 Pearson Education, Inc. Chapter Table of Contents

10.8 There are two modern fish lineages

that lack a jaw.

Hagfishes have a skull

but lack a recognizable

backbone.

Lampreys have a skull

and backbone, but they

lack a jaw.


10.8 The first vertebrates with jaws were

cartilaginous fishes.

• Cartilaginous fishes have flexible

skeletons made of cartilage and must

constantly move to keep water flowing

through the gills.

• Most are marine predators.


10.8 There are more species of bony fishes

than any other group of vertebrates.

• Bony fishes were the first group to have

internal skeletons reinforced with calcium.

• They also have a swim bladder to maintain

buoyancy, and an operculum that

circulates water over the gills.


10.8 A gallery of bony fishes

Thorny seahorseChevron barracuda

Spotfin butterflyfishRainbow trout


10.8 The lobe-finned fishes are an

evolutionary branch of the bony fishes.

• Lobe-finned fishes have muscular fins

supported by rod-shaped bones that are

homologous to amphibian limb bones.

The lobe-fins include

the lungfishes.


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10.9 Opening Questions: Name the phyla.

On a trip to the ocean you spot the following organisms.

To which phyla does each organism belong?

Orange elephant

ear sponge (Agelas clathrodes)

Brain coral(Colpophyllia natans)

Banana slug (Ariolimax californicus)

Bay scallop (Argopecten irradians)

Brittle star (Ophiothrix fragilis)

Tunicates(Atriolum robustum)

Southern stingray(Dasyatis americana)

Goosenecked

barnacles (Lepas pectinata)


10.9 Amphibians and reptiles have four

limbs and were the first to occupy land.

• All terrestrial

vertebrates are

tetrapods, animals

with four limbs.

• Amphibians were

the first tetrapods.

• They were followed

by the evolution of

reptiles (including

birds).


10.9 Amphibians live on land, but must

reproduce in water.

• Amphibians exhibit a

blend of aquatic and

terrestrial adaptations.

• Aquatic adaptations:

– Eggs that lack shells

– Tadpole stage has gills

• Terrestrial adaptations:

– Adult has lungs

– Musculoskeletal system

with four limbs

– Moist skin


10.9 A gallery of amphibians


Frogs have powerful hind

legs that allow hopping.

Toads live entirely on land.

Caecilians superficially resemble

earthworms or snakes.

Salamanders can be either aquatic

or terrestrial.

10.9 Reptiles, including birds, can complete

their entire life cycle on land.

• Reptiles (and mammals) are amniotes,

animals that develop inside a fluid-filled

amniotic egg.

• One hypothesis places reptiles into four

groups, although this a subject of debate.


10.9 Four major reptile groups


Crocodilians

Turtles Dinosaurs and birds

Lizards and snakes


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10.9 Fossils suggest that birds are part of a

dinosaur group called theropods.

• Birds display many adaptations for flight.


10.10 Opening Questions: Tastes like dino?

• Identify three similarities and three

differences between modern birds

(such as a chicken)

and pre-avian

dinosaurs.


10.10 Mammals are tetrapods that have hair

and produce milk in mammary glands.

• After the dinosaur mass

extinction 65 mya,

mammals rapidly

diversified.

• Modern mammals can

be divided into three

groups:

– Monotremes

– Marsupials

– Eutherians


10.10 Monotremes are the only surviving

egg-laying mammals.

• The only modern monotremes are the

duck-billed platypus and four species of

echidna.


Short-beaked echidna The duck-billed platypusChapter Table of Contents

10.10 Marsupials mature in pouches.

• After a brief pregnancy, a marsupial gives

birth to a tiny embryonic offspring that

completes its development in its mother’s

pouch, attached to a nipple.


10.10 Most marsupials are found in

Australia.

• Australia split off from the other continents

around 60 mya.

• Isolated from the evolution of later groups

of mammals, marsupials diversified

extensively.


Eastern gray kangaroo

with offspring


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10.10 Eutherian offspring are born fully

developed after maturing with a placenta.

• The placenta of a

eutherian connects

the developing fetus

to the uterine wall.

• This allows nutrient

uptake, waste

elimination, and gas

exchange via the

mother’s blood

supply.


Many mammals are

born encased in an

amniotic sac.


10.10 A gallery of eutherians

There are about 80 species of

cetaceans, or aquatic mammals.

There are about

1,000 species of bats.

Most mammals, such as this dog,

are terrestrial.


10.11 Opening Questions: When did we

arrive?

• Imagine the history of life

on Earth compressed into

a single 24-hour day.

• The clock starts ticking

at 5,000 mya and

goes to the present

(hour 24:midnight).


• At what time would you put the appearance

of our species, Homo sapiens?

12 Noon

2,500 mya

18:00

1,250

mya

06:00

3,750

mya


10.11 Where do humans sit on the tree of

life on Earth?

• Humans are in the phylum of chordates

and are mammals who belong to the order

of primates.


pg 246

10.11 As a group, primates share some

distinctive characteristics.

Primate characteristics:

– Large brains

– Binocular vision

– Limber joints, limbs, and

digits

– Complex behaviors

– Extended parental care

• Primates are further divided into the

nonanthropoids and the anthropoids.


10.11 Humans evolved from ancestral

primates several million years ago.

• Fossil and DNA evidence suggest that the

human lineage, the hominins, split from

other primates around 5 to 7 million years

ago.

• Many lineages evolved, but only one, ours,

has survived.


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10.11 Highlights in the timeline of human

evolution

• Many of the features that distinguish

modern humans appeared long

before our species, Homo sapiens.

~ 4.0 to 2.9 mya:Australopithecus afarensis

− The earliest known hominin

to display a key human trait:

bipedalism. Found in Africa.

Fossil hominin

skeleton known as LucyChapter Table of Contents© 2017 Pearson Education, Inc.


evolution

~ 2.4 to 1.7 mya: Homo habilis

− Intermediate in brain size with

evidence for tool use.

− The oldest known member of our

own genus.

~ 1.8 to 1.3 mya: Homo erectus

− The first hominin species

known to have migrated out

of Africa to other continents.



evolution

~ 350,000 to 30,000 years ago: Homo neanderthalensis− DNA analysis suggests that

Neanderthals and H. sapiens were

not direct relatives but most likely

interbred.

~ 200,000 years ago to present:Homo sapiens

− From Africa, our species spread

into Asia (approximately 50,000

years ago), and then to Europe

and Australia.


10.11 A few important points about human

evolution

• Humans did not evolve from chimps.

– We share a common ancestor.

• Human evolution did not proceed from one

species to the next.

– Human evolution is not an orderly procession

and many species coexisted.

• Key human features did not evolve all at

once.

– Features, such as upright posture and speech,

evolved separately and at different times.


10.11 When did we arrive?

• Imagine the history of life

on Earth compressed into

a single 24-hour day.

• The clock starts ticking at

5,000 mya and goes to the

present (hour 24:midnight). 12 Noon

2,500 mya

18:00

1,250

mya

06:00

3,750

mya

• Genus Homo – arrives at just around 34

seconds before midnight (~ 2 mya).

• Homo sapiens – arrives less than 4

seconds before midnight (~ 0.2 mya)!


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