17 lecture presentation
TRANSCRIPT
© 2010 Pearson Education, Inc.
Chapter 17
© 2010 Pearson Education, Inc.
What Is an Animal?• Animals are:
– Eukaryotic
– Multicellular
– Heterotrophic organisms that obtain nutrients by ingestion
– Able to digest their food within their bodies
• Animal cells lack the cell walls that provide strong support in the bodies of plants and fungi.
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• Most animals have:
– Muscle cells
– Nerve cells that control the muscles
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• Most animals:
– Are diploid
– Reproduce sexually
– Proceed through a series of typically similar developmental stages
MEIOSIS
Sperm
Egg
Adult
Key
FERTILIZATION
MITOSIS
Eight-cell stage
Internal sac
Digestive tract
Larva
METAMORPHOSIS
Haploid (n)
Diploid (2n)
Outer cell layer(ectoderm)
Later gastrula(cross section)
Future middlelayer of cells(mesoderm)
Inner cell layer(endoderm)
Early gastrula(cross section)
Blastula(cross section)
Zygote(fertilized egg)
Figure 17.2-8
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Animal Phylogeny• Biologists categorize animals by:
– General features of body structure
– More recently, using genetic data
Ancestralprotist
No true tissues
Radial symmetry
Tissues
Bilateral symmetry
Sponges
Cnidarians
Molluscs
Flatworms
Annelids
Roundworms
Arthropods
Echinoderms
Chordates
Figure 17.5
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• A second major evolutionary split is based on body symmetry.
– Radial symmetry refers to animals that are identical all around a central axis.
– Bilateral symmetry exists where there is only one way to split the animal into equal halves.
Radial symmetry. Parts radiate from the center, so any slicethrough the central axis divides into mirror images.
Bilateral symmetry. Only one slice can divide left and rightsides into mirror-image halves.
Figure 17.6
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• Animals also vary according to the presence and type of body cavity, a fluid-filled space separating the digestive tract from the outer body wall.
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• There are differences in how the body cavity forms.
– If the body cavity is not completely lined by tissue derived from mesoderm, it is a pseudocoelom.
– A true coelom is completely lined by tissue derived from mesoderm.
(a) No body cavity
(b) Pseudocoelom
(c) True coelom
Body covering(from ectoderm)
Tissue-filledregion (frommesoderm)
Body covering(from ectoderm)
Body covering(from ectoderm)
Musclelayer (frommesoderm)
Tissue layer liningcoelom andsuspendinginternal organs(from mesoderm)
Digestive tract(from endoderm)
Digestive tract(from endoderm)
Digestive tract(from endoderm)
Pseudocoelom
Coelom
Figure 17.7
(a) No body cavity: for example, flatworm
Body covering(from ectoderm)
Tissue-filledregion (frommesoderm)
Digestive tract(from endoderm)
Figure 17.7a
(b) Pseudocoelom: a body cavity only partiallylined by the mesoderm, the middle tissue layer;for example, roundworm
Body covering(from ectoderm)
Musclelayer (frommesoderm)
Digestive tract(from endoderm)
Pseudocoelom
Figure 17.7b
(c) True coelom: a fluid-filled body cavity completelylined by mesoderm, for example, annelid
Body covering(from ectoderm)
Tissue layer liningcoelom andsuspendinginternal organs(from mesoderm)Digestive tract
(from endoderm)
Coelom
Figure 17.7c
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MAJOR INVERTEBRATE PHYLA• Invertebrates:
– Are animals without backbones
– Represent 95% of the animal kingdom
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Sponges• Sponges
• Sponges include sessile animals that lack true tissues and that were once believed to be plants.
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• The body of a sponge resembles a sac perforated with holes.
• Choanocyte cells draw water through the walls of the sponge where food is collected.
Choanocyte(feeding cell)
Waterflow
Skeletalfiber
Centralcavity
Choanocytein contactwith anamoebocyte
Amoebocyte
Flagella
Pores
Figure 17.8
Waterflow
Skeletalfiber
Centralcavity
Choanocytein contactwith anamoebocyte
Amoebocyte
Flagella
Pores
Choanocyte(feeding cell)
Figure 17.8a
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Cnidarians• Cnidarians (phylum Cnidaria) are characterized by:
– The presence of body tissues
– Radial symmetry
– Tentacles with stinging cells
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• The basic body plan of a cnidarian is a sac with a gastrovascular cavity, a central digestive compartment with only one opening.
• The body plan has two variations:
– The sessile polyp
– The floating medusa
Mouth/anus
Tentacle
Polyp form
Gastrovascularcavity
Coral Hydra
Sea anemone
Gastrovascularcavity
Mouth/anusTentacle
Medusa form
JellyFigure 17.9
Mouth/anus
Tentacle
Polyp form
Gastrovascularcavity
Coral Hydra
Sea anemone
Figure 17.9a
Mouth/anus
Tentacle
Polyp form
Gastrovascularcavity
Figure 17.9aa
CoralFigure 17.9ab
Sea anemoneFigure 17.9ac
HydraFigure 17.9ad
Gastrovascularcavity
Mouth/anusTentacle
Medusa form
Jelly
Figure 17.9b
Gastrovascularcavity
Mouth/anus
Tentacle
Medusa formFigure 17.9ba
Jelly
Figure 17.9bb
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• Cnidarians are carnivores that use tentacles, armed with cnidocytes (“stinging cells”), to capture prey.
Tentacle
Trigger
Capsule
Cnidocyte
Dischargeof thread
Prey
Coiledthread
Figure 17.10
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Molluscs• Molluscs (phylum Mollusca) are represented by soft-bodied
animals, usually protected by a hard shell.
• Many molluscs feed by using a file-like organ called a radula to scrape up food.
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• The body of a mollusc has three main parts:
– A muscular foot used for movement
– A visceral mass housing most of the internal organs
– A mantle, which secretes the shell if present
Visceral mass
Reproductiveorgans
Digestivetract
Mantlecavity
Nervecords
Digestivetract
Coelom
Radula
Radula
Kidney Heart
Shell
Mouth
Mouth
Anus
Gill
Foot
Mantle
Figure 17.11
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• The three major groups of molluscs are:
– Gastropods, protected by a single, spiraled shell
Snail (spiraled shell)
Figure 17.12aa
Sea slug (no shell)
Figure 17.12ab
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– Bivalves, with a shell divided into two halves hinged together
Bivalves(hinged shell)
ScallopFigure 17.12b
Octopus
Figure 17.12ca
Squid
Figure 17.12cb
Gastropods Bivalves(hinged shell)
Cephalopods(large brain and tentacles)
Snail (spiraled shell)
Sea slug (no shell)
Scallop Octopus Squid
MAJOR GROUPS OF MOLLUSCS
Figure 17.12
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Flatworms• Flatworms (phylum Platyhelminthes) are the simplest bilateral
animals.
• Flatworms include forms that are:
– Parasites or
– Free-living in marine, freshwater, or damp habitats
Head
Sucker
Reproductive unitwith skin removed
Tapeworm
Figure 17.13ba
Blood fluke
Figure 17.13c
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• The gastrovascular cavity of flatworms
– Is highly branched
– Provides an extensive surface area for absorption of nutrients
Digestive tract(gastrovascularcavity)
Nerve cords
Mouth
Eyespots (detect light)
Nervous tissue clusters(simple brain)
Planarian
Bilateral symmetry
Figure 17.13a
Digestive tract(gastrovascularcavity) Nerve cords
Mouth
Eyespots(detect light)
Nervous tissueclusters(simple brain)
Planarian Bilateral symmetry
Blood fluke
Head Hooks
Suckers
Reproductive unitwith skin removed
Tapeworm
Figure 17.13
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Annelids• Annelids (phylum Annelida) have:
– Body segmentation, a subdivision of the body along its length into a series of repeated parts
– A coelom
– A complete digestive tract with
– Two openings, a mouth and anus
– One-way movement of food
Mouth
Brain
Coelom
Nerve cord
Blood vesselsWaste disposal organ
Anus
Accessoryhearts
Mainheart
Digestivetract
Segmentwalls
Figure 17.15
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• The three main groups of annelids are:
– Earthworms, which eat their way through soil
– Polychaetes, marine worms with segmental appendages for movement and gas exchange
– Leeches, typically free-living carnivores but with some bloodsucking forms
Video: Earthworm Locomotion
Earthworms
Giant Australian earthwormFigure 17.14a
Polychaetes
Christmas tree worm
Figure 17.14b
Leeches
European freshwater leechFigure 17.14c
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Roundworms• Roundworms (phylum Nematoda) are:
– Cylindrical in shape, tapered at both ends
– The most diverse and widespread of all animals
• Roundworms (also called nematodes) are:
– Important decomposers
– Dangerous parasites in plants, humans, and other animals
Video: C. elegans Embryo Development (time lapse)
Video: C. elegans Crawling
(a) A free-living roundwormFigure 17.16a
(b) Parasitic roundworms in porkFigure 17.16b
(c) Canine heart infected withparasitic roundworms
Figure 17.16c
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Arthropods• Arthropods (phylum Arthropoda) are named for their jointed
appendages.
• There are about one million arthropod species identified, mostly insects.
• Arthropods are a very diverse and successful group, occurring in nearly all habitats in the biosphere.
• There are four main groups of arthropods.
MAJOR GROUPS OF ARTHROPODS
Arachnids
Crustaceans
Millipedes and Centipedes
Insects
Figure 17.17
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General Characteristics of Arthropods
• Arthropods are segmented animals with specialized segments and appendages for an efficient division of labor among body regions.
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• The body of arthropods is completely covered by an exoskeleton, an external skeleton that provides:
– Protection
– Points of attachment for the muscles that move appendages
Video: Lobster Mouth Parts
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• Arachnids:
– Live on land
– Usually have four pairs of walking legs and a specialized pair of feeding appendages
– Include spiders, scorpions, ticks, and mites
Arachnids
Two feedingappendages
Leg (four pairs)
Black widow spider Wood tick
Dust miteScorpion
Figure 17.19
Two feedingappendages
Leg (four pairs)
Tarantula spider (an arachnid)Figure 17.19a
ScorpionFigure 17.19b
Black widow spider
Figure 17.19c
Dust miteFigure 17.19d
Wood tick
Figure 17.19e
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• Crustaceans:
– Are nearly all aquatic
– Have multiple pairs of specialized appendages
– Include crabs, lobsters, crayfish, shrimps, and barnacles
Crustaceans
AbdomenCephalothorax
(head and thorax)
Swimmingappendage
Antenna(sensory reception)
Eyes onmovable stalks
Mouthparts (feeding)
Walking leg
Walking legs
Figure 17.18
Two feedingappendages Leg (three or more pairs)
Antennae
BarnaclesCrayfish
Pill bugShrimp
Crab
Figure 17.20
Two feedingappendages
Leg (three or more pairs)
Antennae
Crab (a crustacean)
Figure 17.20a
Crab
Figure 17.20b
Shrimp
Figure 17.20c
Pill bug
Figure 17.20d
Crayfish
Figure 17.20e
Barnacles
Figure 17.20f
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• Millipedes and centipedes have similar segments over most of the body.
• Millipedes:
– Eat decaying plant matter
– Have two pairs of short legs per body segment
• Centipedes:
– Are terrestrial carnivores with poison claws
– Have one pair of short legs per body segment
Millipedes and Centipedes
One pair of legs per segment
Two pairs of legsper segment
Millipede Centipede
Figure 17.21
Two pairs of legsper segment
MillipedeFigure 17.21a
One pair of legs per segment
CentipedeFigure 17.21b
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• Insects typically have a three-part body:
– Head
– Thorax
– Abdomen
Insect Anatomy
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• The insect head usually bears:
– A pair of sensory antennae
– A pair of eyes
• The mouthparts are adapted for particular kinds of eating.
• Flight is one key to the great success of insects.
Antenna
Head Thorax Abdomen
Eye
Mouthparts
Figure 17.22
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• Insects outnumber all other forms of life combined.
• Insects live in:
– Almost every terrestrial habitat
– Freshwater
– The air
Insect Diversity
Banded OrangeHeliconian
PrayingmantisGiraffe weevil
Yellow jacket wasp Leaf beetle
Leaf roller
Peacock katydid
Longhorn beetleFigure 17.23
Peacock katydidFigure 17.23a
Banded Orange HeliconianFigure 17.23b
Giraffe weevilFigure 17.23c
Yellow jacket waspFigure 17.23d
Leaf beetle
Figure 17.23e
Longhorn beetleFigure 17.23f
Praying mantisFigure 17.23g
Leaf rollerFigure 17.23h
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• Many insects undergo metamorphosis in their development.
• Young insects may:
– Appear to be smaller forms of the adult or
– Change from a larval form to something much different as an adult
Video: Butterfly Emerging
The larva (caterpillar) spendsits time eating and growing,molting as it grows.
After several molts, thelarva becomes a pupaencased in a cocoon.
Within the pupa, the larval organs breakdown and adult organs develop fromcells that were dormant in the larva.
Finally, the adult emergesfrom the cocoon.
The butterfly flies off and reproduces, nourished mainlyby calories stored when it was a caterpillar.
Figure 17.24-5
Monarch butterflies
Figure 17.24a
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Echinoderms• Echinoderms (phylum Echinodermata):
– Lack body segments
– Typically show radial symmetry as adults but bilateral symmetry as larvae
– Have an endoskeleton
– Have a water vascular system that facilitates movement and gas exchange
• Echinoderms are a very diverse group.
Video: Echinoderm Tube Feet
Sea star
Sea urchin
Sea cucumber Sand dollar
Tube feet
Figure 17.25
Sea star
Figure 17.25a
Sea star Figure 17.25aa
Sea star Figure 17.25ab
Sea starsFigure 17.25ac
Sea urchin
Tube feet
Figure 17.25b
Sea cucumber
Figure 17.25c
Sand dollarFigure 17.25d
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VERTEBRATE EVOLUTION AND DIVERSITY
• Vertebrates have unique endoskeletons composed of:
– A cranium (skull)
– A backbone made of a series of bones called vertebrae
Vertebra
Cranium(protects brain)
Figure 17.26
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Characteristics of Chordates• Chordates (phylum Chordata) all share four key features that
appear in the embryo and sometimes the adult:
– A dorsal, hollow nerve cord
– A notochord
– Pharyngeal slits
– A post-anal tail
Muscle segments
Notochord
Dorsal,
hollow
nerve cord
Pharyngeal
slits
Brain
Mouth
Anus
Post-anal
tail
Figure 17.27
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• Another chordate characteristic is body segmentation, apparent in the:
– Backbone of vertebrates
– Segmental muscles of all chordates
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• Chordates consists of three groups of invertebrates:
– Lancelets are bladelike animals without a cranium.
– Tunicates, or sea squirts, also lack a cranium.
– Hagfishes are eel-like forms that have a cranium.
• All other chordates are vertebrates.
Mouth
Tail
Lancelet Tunicates
Figure 17.28
Mouth
Tail
LanceletFigure 17.28a
Tunicates Figure 17.28b
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THE HUMAN ANCESTRY• Humans are primates, the mammalian group that also includes:
– Lorises
– Pottos
– Lemurs
– Tarsiers
– Monkeys
– Apes
Ancestralprimate
Lemurs, lorises,and pottos
Tarsiers
New World monkeys
Old World monkeys
Gibbons
Orangutans
Gorillas
Chimpanzees
Humans
An
thro
po
ids
Mo
nk
ey
sA
pe
s
Figure 17.36
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• Primates evolved from insect-eating mammals during the late Cretaceous period.
The Evolution of Primates
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• Primates are distinguished by characteristics that were shaped by the demands of living in trees. These characteristics include:
– Limber shoulder joints
– Eyes in front of the face
– Excellent eye-hand coordination
– Extensive parental care
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• Taxonomists divide the primates into three main groups.
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• The first group of primates includes:
– Lorises
– Pottos
– Lemurs
Ring-tailed lemurFigure 17.37a
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• Tarsiers form the second group.
TarsierFigure 17.37b
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• The third group, anthropoids, includes:
– Monkeys
Patas monkey (Old World monkey)Figure 17.37d
Black spider monkey(New World monkey)
Figure 17.37c
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– Hominoids, the ape relatives of humans
Video: Gibbons Brachiating
Video: Chimp Cracking Nut
Video: Chimp Agonistic Behavior
Gibbon (ape)Figure 17.37e
Gorilla (ape)Figure 17.37g
Orangutan (ape)Figure 17.37f
Chimpanzee (ape)Figure 17.37h
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– And humans
HumanFigure 17.37i
Ring-tailedlemur
Tarsier
Black spider monkey(New World monkey)
Patas monkey (Old World monkey)
Gorilla (ape)
Gibbon (ape)
Chimpanzee (ape)
Orangutan (ape)
HumanFigure 17.37
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The Emergence of Humankind• Humans and chimpanzees have shared a common African
ancestry for all but the last 5–7 million years.
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Some Common Misconceptions
• Chimpanzees and humans represent two divergent branches of the anthropoid tree that each evolved from a common, less specialized ancestor.
• Our ancestors were not chimpanzees or any other modern apes.
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• Human evolution is not a ladder with a parade of fossil hominids (members of the human family) leading directly to modern humans.
• Instead, human evolution is more like a multibranched bush than a ladder.
• At times in hominid history, several different human species coexisted.
Ardipithecusramidus
Australopithecusafarensis
Australopithecusafricanus
Paranthropusrobustus
Paranthropusboisei
Homoneanderthalensis
Homosapiens
Homohabilis
Homo erectus
?M
illi
on
s o
f y
ea
rs a
go
6.0
5.0
5.5
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
Figure 17.38
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• Upright posture and an enlarged brain appeared at separate times during human evolution.
• Different human features evolved at different rates.
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Australopithecus and the Antiquity of Bipedalism
• Before there was the genus Homo, several hominid species of the genus Australopithecus walked the African savanna.
• Fossil evidence pushes bipedalism in A. afarensis back to at least 4 million years ago.
(a) Australopithecusafarensis skeleton
(b) Ancient footprints (c) Model of anAustralopithecusafarensis male
Figure 17.39
(a) Australopithecusafarensis skeleton
Figure 17.39a
(b) Ancient footprintsFigure 17.39b
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Homo Habilis and the Evolution of Inventive Minds
• Homo habilis, “handy-man”:
– Had a larger brain, intermediate in size between Australopithecus and modern humans
– Walked upright
– Made stone tools that enhanced hunting, gathering, and scavenging on the African savanna
Homo Erectus and the Global Dispersal of Humanity
• Homo erectus was the first species to extend humanity’s range from Africa to other continents.
• The global dispersal began about 1.8 million years ago.
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• Homo erectus:
– Was taller than H. habilis
– Had a larger brain
– Gave rise to Neanderthals
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The Origin and Dispersal of Homo Sapiens
• The oldest known fossils of our own species, Homo sapiens:
– Were discovered in Ethiopia
– Date from 160,000 to 195,000 years ago
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• DNA studies strongly suggest that all living humans can trace their ancestry back to a single African Homo sapiens woman who lived 160,000 to 200,000 years ago.
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• Fossil evidence suggests that our species emerged from Africa in one or more waves.
• The oldest fossils of H. sapiens outside of Africa are 50,000 years old.
• The oldest fossils of humans in the New World are uncertain, but are at least 15,000 years old.
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Cultural Evolution
• Culture is the social transmission of accumulated knowledge, customs, beliefs, and art over generations.
• Culture is primarily transmitted by language.
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• Cultural evolution has had three major stages.
– First, nomads who were hunter-gatherers:
– Made tools
– Organized communal activities
– Divided labor
– Created art
Figure 17.41
Figure 17.41a
Figure 17.41b
Figure 17.41c
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– The second main stage of cultural evolution was the development of agriculture in Africa, Eurasia, and the Americas, about 10,000 to 15,000 years ago.
– The third stage was the Industrial Revolution, which began in the 1700s.
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• The global consequences of human evolution have been enormous. Humans can:
– Defy our physical limitation
– Shortcut biological evolution
– Change the environment to meet our needs
Figure 17.42
Figure 17.43
Ancestralprotist
True tissues
Bilateral symmetry
Sponges
Cnidarians
Molluscs
Flatworms
Annelids
Roundworms
Arthropods
Echinoderms
Chordates
Figure 17.UN15
Radial symmetry Bilateral symmetry
Figure 17.UN18
Gastropods Bivalves Cephalopods
MOLLUSCS
Figure 17.UN19
Arachnids
ARTHROPODS
Crustaceans InsectsMillipedesand Centipedes
Figure 17.UN20
Monotremes
MAMMALS
Marsupials Eutherians
Figure 17.UN21