Animals and Animal Diversity

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Animals and Animal Diversity

• The Nitty-gritty!

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Note

• There is no red on this powerpoint, all
  non-essentials were deleted from the notes.
• Just imagine that everything is in red!

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Basic Characteristics
Ch 32?

• Multicellular
• Heterotrophic
• Mobile
• Eukaryotic
• Lack cell walls
• Bodies are held together by structural proteins
  like collagen
• Nervous and muscular tissue unique to animal
  kingdom

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Reproduction and Development

• Most reproduce sexually, with the diploid stage
  usually dominating the life cycle
• After a sperm fertilizes an egg, the zygote
  undergoes rapid cell division called cleavage
• Cleavage leads to formation of a blastula
• The blastula undergoes gastrulation, forming a
  gastrula with different layers of embryonic
  tissues

Video Sea Urchin Embryonic Development
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Fig. 32-2-3
Blastocoel
Endoderm
Cleavage
Cleavage
Blastula
Ectoderm
Archenteron
Zygote
Eight-cell stage
Gastrulation
Gastrula
Blastocoel
Blastopore
Cross section of blastula
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• Many animals have at least one larval stage
  (sexually immature morphology that is different
  from the adult), which eventually undergoes
  metamorphosis
• All animals, and only animals, have Hox genes
  that regulate the development of body form

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Paleozoic Era (542251 Million Years Ago) The
rise of the animal kingdom

• The Cambrian explosion (535 to 525 million years
  ago) marks the earliest fossil appearance of many
  major groups of living animals
• There are several hypotheses regarding the cause
  of the Cambrian explosion
• New predator-prey relationships
• A rise in atmospheric oxygen
• The evolution of the Hox gene complex

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Concept 32.3 Animals can be characterized by
body plans

• Zoologists sometimes categorize animals according
  to a body plan, a set of morphological and
  developmental traits

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Symmetry
Radial

• Animals can be categorized according to the
  symmetry of their bodies, or lack of it
• Some animals have radial symmetry, while others
  show bilateral symmetry.

Bilateral
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• Two-sided symmetry is called bilateral symmetry
• Bilaterally symmetrical animals have
• A dorsal (top) side and a ventral (bottom) side
• A right and left side
• Anterior (head) and posterior (tail) ends
• Cephalization, the development of a head

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Tissues

• Animal body plans also vary according to the
  organization of the animals tissues
• Tissues are collections of specialized cells
  isolated from other tissues by membranous layers
• During development, three germ layers give rise
  to the tissues and organs of the animal embryo

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• Ectoderm is the germ layer covering the embryos
  surface
• Endoderm is the innermost germ layer and lines
  the developing digestive tube, called the
  archenteron
• Diploblastic animals have ectoderm and endoderm
• Triploblastic animals also have an intervening
  mesoderm layer these include all bilaterians

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Body Cavities

• Most triploblastic animals possess a body cavity
• A true body cavity is called a coelom and is
  derived from mesoderm
• Coelomates are animals that possess a true coelom

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Fig. 32-8a
Coelom
Body covering (from ectoderm)
Tissue layer lining coelom and suspending internal
organs (from mesoderm)
Digestive tract (from endoderm)
(a) Coelomate
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• A pseudocoelom is a body cavity derived from the
  mesoderm and endoderm
• Triploblastic animals that possess a pseudocoelom
  are called pseudocoelomates

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Fig. 32-8b
Body covering (from ectoderm)
Pseudocoelom
Muscle layer (from mesoderm)
Digestive tract (from endoderm)
(b) Pseudocoelomate
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• Triploblastic animals that lack a body cavity are
  called acoelomates

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Fig. 32-8c
Body covering (from ectoderm)
Tissue- filled region (from mesoderm)
Wall of digestive cavity (from endoderm)
(c) Acoelomate
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Protostome and Deuterostome Development

• Based on early development, many animals can be
  categorized as having protostome development or
  deuterostome development

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Cleavage

• In protostome development, cleavage is spiral and
  determinate
• In deuterostome development, cleavage is radial
  and indeterminate
• With indeterminate cleavage, each cell in the
  early stages of cleavage retains the capacity to
  develop into a complete embryo
• Indeterminate cleavage makes possible identical
  twins, and embryonic stem cells

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Fig. 32-9
Protostome development (examples
molluscs, annelids)
Deuterostome development (examples
echinoderm, chordates)
(a) Cleavage
Eight-cell stage
Eight-cell stage
Spiral and determinate
Radial and indeterminate
(b) Coelom formation
Key
Coelom
Ectoderm
Mesoderm
Archenteron
Endoderm
Coelom
Mesoderm
Blastopore
Mesoderm
Blastopore
Solid masses of mesoderm split and form coelom.
Folds of archenteron form coelom.
(c) Fate of the blastopore
Anus
Mouth
Digestive tube
Mouth
Anus
Mouth develops from blastopore.
Anus develops from blastopore.
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Fig. 32-9a
Deuterostome development (examples
echinoderms, chordates)
Protostome development (examples
molluscs, annelids)
(a) Cleavage
Eight-cell stage
Eight-cell stage
Spiral and determinate
Radial and indeterminate
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Coelom Formation

• In protostome development, the splitting of solid
  masses of mesoderm forms the coelom
• In deuterostome development, the mesoderm buds
  from the wall of the archenteron to form the
  coelom

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Fig. 32-9b
Protostome development (examples
molluscs, annelids)
Deuterostome development (examples
echinoderms, chordates)
(b) Coelom formation
Coelom
Key
Ectoderm
Archenteron
Mesoderm
Endoderm
Coelom
Mesoderm
Blastopore
Blastopore
Mesoderm
Solid masses of mesoderm split and form coelom.
Folds of archenteron form coelom.
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Fate of the Blastopore

• The blastopore forms during gastrulation and
  connects the archenteron to the exterior of the
  gastrula
• In protostome development, the blastopore becomes
  the mouth
• In deuterostome development, the blastopore
  becomes the anus

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Fig. 32-9c
Protostome development (examples
molluscs, annelids)
Deuterostome development (examples
echinoderms, chordates)
(c) Fate of the blastopore
Anus
Mouth
Key
Ectoderm
Digestive tube
Mesoderm
Endoderm
Anus
Mouth
Mouth develops from blastopore.
Anus develops from blastopore.
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Modeling Time

• Lets go back to the lab.
• Take a sheet of paper with you
• Pick up a direction sheet
• Get 2 colors of dough

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Invertebrates

• Those without backbones make up about 95 of
  animals

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Fig. 33-2
Calcarea and Silicea
ANCESTRAL PROTIST
Cnidaria
Lophotrochozoa
Common ancestor of all animals
Eumetazoa
Ecdysozoa
Bilateria
Deuterostomia
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Sponges

• Lack true tissues and organs
• Live in water (both fresh and salt)
• suspension feeders, capturing food particles
  suspended in the water that pass through their
  body
• Most sponges are hermaphrodites Each individual
  functions as both male and female

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Fig. 33-4
Food particles in mucus
Flagellum
Choanocyte
Collar
Choanocyte
Osculum
Azure vase sponge (Callyspongia plicifera)
Spongocoel
Phagocytosis of food particles
Amoebocyte
Pore
Spicules
Epidermis
Water flow
Amoebocytes
Mesohyl
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Cnidarians

• include jellies, corals, and hydras
• exhibit a relatively simple diploblastic, radial
  body plan
• body plan is a sac with a central digestive
  compartment, the gastrovascular cavity
• A single opening functions as mouth and anus
• There are two variations on the body plan the
  sessile polyp and motile medusa
• Carnivores that use tentacles to capture prey
• Armed with enidocytes cells that fxn in defense
  and capturing prey
• Nematocysts organelles that eject a stinging
  thread

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Fig. 33-5
Mouth/anus
Tentacle
Polyp
Medusa
Gastrovascular cavity
Gastrodermis
Mesoglea
Body stalk
Epidermis
Tentacle
Mouth/anus
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Fig. 33-6
Tentacle
Cuticle of prey
Thread
Nematocyst
Trigger
Thread discharges
Thread (coiled)
Cnidocyte
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Flatworms

• live in marine, freshwater, and damp terrestrial
  habitats
• acoelomates
• They are flattened dorsoventrally and have a
  gastrovascular cavity
• Gas exchange takes place across the surface

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Fig. 33-10
Pharynx
Gastrovascular cavity
Mouth
Eyespots
Ganglia
Ventral nerve cords
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Tapeworms

• Tapeworms are parasites of vertebrates and lack a
  digestive system
• Tapeworms absorb nutrients from the hosts
  intestine
• Fertilized eggs, produced by sexual reproduction,
  leave the hosts body in feces

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Rotifers

• Rotifers are tiny animals that inhabit fresh
  water, the ocean, and damp soil
• Rotifers have an alimentary canal, a digestive
  tube with a separate mouth and anus that lies
  within a fluid-filled pseudocoelom
• Rotifers reproduce by parthenogenesis, in which
  females produce offspring from unfertilized eggs
• Some species are unusual in that they lack males
  entirely

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Mollusca

• Phylum Mollusca includes snails and slugs,
  oysters and clams, and octopuses and squids
• Most molluscs are marine
• Molluscs are soft-bodied animals, but most are
  protected by a hard shell
• All molluscs have a similar body plan with three
  main parts
• Muscular foot
• Visceral mass
• Mantle
• Many molluscs also have a water-filled mantle
  cavity, and feed using a rasplike radula

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Fig. 33-15
Nephridium
Visceral mass
Heart
Coelom
Intestine
Gonads
Mantle
Stomach
Mantle cavity
Mouth
Shell
Radula
Anus
Gill
Radula
Mouth
Nerve cords
Esophagus
Foot
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Gastropods

• Most gastropods are marine,
• Most have a single, spiraled shell
• Slugs lack a shell or have a reduced shell
• The most distinctive characteristic of gastropods
  is torsion, which causes the animals anus and
  mantle to end up above its head

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Fig. 33-17
(a) A land snail
(b) A sea slug
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Fig. 33-18
Intestine
Mantle cavity
Stomach
Anus
Mouth
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Bivalves

• Molluscs of class Bivalvia include many species
  of clams, oysters, mussels, and scallops
• They have a shell divided into two halves
• The mantle cavity of a bivalve contains gills
  that are used for feeding as well as gas exchange

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Fig. 33-19
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Fig. 33-20
Coelom
Hinge area
Mantle
Gut
Heart
Adductor muscle
Digestive gland
Anus
Mouth
Excurrent siphon
Shell
Water flow
Palp
Foot
Incurrent siphon
Mantle cavity
Gonad
Gill
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Cephalopods
Octopus

• Class Cephalopoda includes squids and octopuses,
  carnivores with beak-like jaws surrounded by
  tentacles of their modified foot
• Cephalopods have a closed circulatory system,
  well-developed sense organs, and a complex brain

Squid
Chambered nautilus
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Annelids

• Annelids have bodies composed of a series of
  fused rings

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Concept 33.4 Ecdysozoans are the most
species-rich animal group

• Ecdysozoans are covered by a tough coat called a
  cuticle
• The cuticle is shed or molted through a process
  called ecdysis
• The two largest phyla are nematodes and arthropods

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Nematodes

• Nematodes, or roundworms, are found in most
  aquatic habitats, in the soil, in moist tissues
  of plants, and in body fluids and tissues of
  animals
• They have an alimentary canal, but lack a
  circulatory system
• Reproduction in nematodes is usually sexual, by
  internal fertilization
• Some are parasitic

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Arthropods

• The arthropod body plan consists of a segmented
  body, hard exoskeleton, and jointed appendages,

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Fig. 33-29
Cephalothorax
Abdomen
Antennae (sensory reception)
Thorax
Head
Swimming appendages (one pair located under
each abdominal segment)
Walking legs
Pincer (defense)
Mouthparts (feeding)
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• The body of an arthropod is completely covered by
  the cuticle, an exoskeleton made of layers of
  protein and the polysaccharide chitin
• When an arthropod grows, it molts its exoskeleton
• Arthropods have an open circulatory system in
  which fluid called hemolymph is circulated into
  the spaces surrounding the tissues and organs

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Echinoderms

• Sea stars and most other echinoderms are
  slow-moving or sessile marine animals
• A thin epidermis covers an endoskeleton of hard
  calcareous plates
• Echinoderms have a unique water vascular system,
  a network of hydraulic canals branching into tube
  feet that function in locomotion, feeding, and
  gas exchange
• Males and females are usually separate, and
  sexual reproduction is external

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Fig. 33-39
Stomach
Anus
Spine
Gills
Central disk
Digestive glands
Madreporite
Radial nerve
Gonads
Ring canal
Ampulla
Podium
Tube feet
Radial canal
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Fig. 33-40
(a) A sea star (class Asteroidea)
(b) A brittle star (class Ophiuroidea)
(c) A sea urchin (class Echinoidea)
(d) A feather star (class Crinoidea)
(e) A sea cucumber (class Holothuroidea)
(f) A sea daisy (class Concentricycloidea)
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Vertebrates

• The ones with backbones

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Chordata

• Four key characters of chordates
• Notochord
• Dorsal, hollow nerve cord
• Pharyngeal slits or clefts
• Muscular, post-anal tail

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Fig. 34-3
Dorsal, hollow nerve cord
Muscle segments
Notochord
Mouth
Anus
Pharyngeal slits or clefts
Muscular, post-anal tail
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• The notochord is a longitudinal, flexible rod
  between the digestive tube and nerve cord
• It provides skeletal support throughout most of
  the length of a chordate
• In most vertebrates, a more complex, jointed
  skeleton develops, and the adult retains only
  remnants of the embryonic notochord
• The nerve cord of a chordate embryo develops from
  a plate of ectoderm that rolls into a tube dorsal
  to the notochord
• The nerve cord develops into the central nervous
  system the brain and the spinal cord

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• In most chordates, grooves in the pharynx called
  pharyngeal clefts develop into slits that open to
  the outside of the body
• Functions of pharyngeal slits
• Suspension-feeding structures in many
  invertebrate chordates
• Gas exchange in vertebrates (except vertebrates
  with limbs, the tetrapods)
• Develop into parts of the ear, head, and neck in
  tetrapods

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• Chordates have a tail posterior to the anus
• In many species, the tail is greatly reduced
  during embryonic development
• The tail contains skeletal elements and muscles
• It provides propelling force in many aquatic
  species

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Early Chordate Evolution

• Ancestral chordates may have resembled lancelets
• Gene expression in lancelets holds clues to the
  evolution of the vertebrate form

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Fig. 34-6
BF1
Otx
Hox3
Nerve cord of lancelet embryo
BF1
Hox3
Otx
Brain of vertebrate embryo (shown straightened)
Hindbrain
Forebrain
Midbrain
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Concept 34.2 Craniates are chordates that have a
head

• The origin of a head opened up a completely new
  way of feeding for chordates active predation
• Craniates share some characteristics a skull,
  brain, eyes, and other sensory organs

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Derived Characters of Craniates

• Craniates have two clusters of Hox genes
  lancelets and tunicates have only one cluster
• One feature unique to craniates is the neural
  crest, a collection of cells near the dorsal
  margins of the closing neural tube in an embryo
• Neural crest cells give rise to a variety of
  structures, including some of the bones and
  cartilage of the skull

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Fig. 34-7
Dorsal edges of neural plate
Neural crest
Neural tube
Migrating neural crest cells
Notochord
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Derived Characters of Vertebrates

• Vertebrates have the following derived
  characters
• Vertebrae enclosing a spinal cord
• An elaborate skull
• Fin rays, in the aquatic forms

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Lampreys

• Lampreys (Petromyzontida) represent the oldest
  living lineage of vertebrates
• They are jawless vertebrates inhabiting various
  marine and freshwater habitats
• They have cartilaginous segments surrounding the
  notochord and arching partly over the nerve cord

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Chondrichthyans (Sharks, Rays, and Their
Relatives)

• Chondrichthyans (Chondrichthyes) have a skeleton
  composed primarily of cartilage
• The cartilaginous skeleton evolved secondarily
  from an ancestral mineralized skeleton
• Includes the sharks, rays, and skates

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Pelvic fins
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Fig. 34-16
Ray-Finned Fishes and Lobe-Fins
Swim bladder
Adipose fin (characteristic of trout)
Dorsal fin
Caudal fin
Spinal cord
Brain
Nostril
Anal fin
Cut edge of operculum
Lateral line
Liver
Gills
Anus
Gonad
Heart
Stomach
Urinary bladder
Pelvic fin
Kidney
Intestine
Fishes control their buoyancy with an air sac
known as a swim bladder
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Fig. 34-17
(a) Yellowfin tuna (Thunnus albacares)
(b) Clownfish (Amphiprion ocellaris)
(c) Sea horse (Hippocampus       ramulosus)
(d) Fine-spotted moray eel (Gymnothorax
dovii)
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Tetrapods

• Tetrapods have some specific adaptations
• Four limbs, and feet with digits
• Ears for detecting airborne sounds

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Fig. 34-19
Bones supporting gills
Tetrapod limb skeleton
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Amphibians

• Amphibian means both ways of life, referring to
  the metamorphosis of an aquatic larva into a
  terrestrial adult
• Most amphibians have moist skin that complements
  the lungs in gas exchange
• Fertilization is external in most species, and
  the eggs require a moist environment

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Fig. 34-22
(a) Tadpole
(b) During metamorphosis
(c) Mating adults
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Concept 34.6 Amniotes are tetrapods that have a
terrestrially adapted egg

• Amniotes are a group of tetrapods whose living
  members are the reptiles, including birds, and
  mammals
• Have an amniotic egg, which contains membranes
  that protect the embryo
• Other terrestrial adaptations include relatively
  impermeable skin and the ability to use the rib
  cage to ventilate the lungs

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Fig. 34-25
Chorion
Allantois
Yolk sac
Amnion
Embryo
Amniotic cavity with amniotic fluid
Yolk (nutrients)
Albumen
Shell
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Reptiles

• Reptiles have scales that create a waterproof
  barrier
• They lay shelled eggs on land
• Most reptiles are ectothermic, absorbing external
  heat as the main source of body heat
• Birds are endothermic, capable of keeping the
  body warm through metabolism

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Fig. 34-26
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Birds

• Many characters of birds are adaptations that
  facilitate flight
• The major adaptation is wings with keratin
  feathers
• Other adaptations include lack of a urinary
  bladder, females with only one ovary, small
  gonads, and loss of teeth

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Fig. 34-28
Finger 1
(b) Bone structure
Palm
(a) Wing
Finger 2
Finger 3
Forearm
Wrist
Shaft
Shaft
Barb
Vane
Barbule
Hook
(c) Feather structure
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Fig. 34-29
Toothed beak
Wing claw
Airfoil wing with contour feathers
Long tail with many vertebrae
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Mammals

• Mammals have
• Mammary glands, which produce milk
• Hair
• A larger brain than other vertebrates of
  equivalent size
• Differentiated teeth

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three living lineages of mammals emerged
monotremes, marsupials, and eutherians

• Monotremes are a small group of egg-laying
  mammals consisting of echidnas and the platypus
• Marsupials when the embryo develops within a
  placenta in the mothers uterus
• A marsupial is born very early in its development
• It completes its embryonic development while
  nursing in a maternal pouch called a marsupium
• eutherians have a longer period of pregnancy
• Young eutherians complete their embryonic
  development within a uterus, joined to the mother
  by the placenta

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Fig. 34-32
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Fig. 34-33
(a) A young brushtail possum
(b) Long-nosed bandicoot
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Fig. 34-34
Marsupial mammals
Eutherian mammals
Marsupial mammals
Eutherian mammals
Plantigale
Deer mouse
Wombat
Woodchuck
Marsupial mole
Mole
Wolverine
Tasmanian devil
Sugar glider
Flying squirrel
Patagonian cavy
Kangaroo
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Primates

• Most primates have hands and feet adapted for
  grasping
• Other derived characters of primates
• A large brain and short jaws
• Forward-looking eyes close together on the face,
  providing depth perception
• Complex social behavior and parental care
• A fully opposable thumb (in monkeys and apes)

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Fig. 34-36
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Fig. 34-38
(a) New World monkey
(b) Old World monkey
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Humans

• A number of characters distinguish humans from
  other apes
• Upright posture and bipedal locomotion
• Larger brains
• Language capabilities and symbolic thought
• The manufacture and use of complex tools
• Shortened jaw
• Shorter digestive tract

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Fig. 34-40
Paranthropus robustus
Homo sapiens
Homo neanderthalensis
0
?
Homo ergaster
Paranthropus boisei
0.5
1.0
Australopithecus africanus
1.5
2.0
Kenyanthropus platyops
2.5
Australopithecus garhi
Australo- pithecus anamensis
Homo erectus
3.0
Millions of years ago
3.5
Homo habilis
Homo rudolfensis
4.0
4.5
Australopithecus afarensis
Ardipithecus ramidus
5.0
5.5
Orrorin tugenensis
6.0
6.5
Sahelanthropus tchadensis
7.0