Chapter 34
Download
1 / 78

Chapter 34 - PowerPoint PPT Presentation


  • 425 Views
  • Updated On :

Chapter 34. Vertebrates. Vertebrates. Get their name from vertebrae, the series of bones that make up the backbone. Vertebrates. There are approximately 52,000 species of vertebrates

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Chapter 34' - Olivia


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Chapter 34 l.jpg

Chapter 34

Vertebrates


Vertebrates l.jpg
Vertebrates

Get their name from vertebrae, the series of bones that make up the backbone


Vertebrates3 l.jpg
Vertebrates

  • There are approximately 52,000 species of vertebrates

    • Which include the largest organisms ever to live on the Earth. Plant-eating dinosaurs at 40,000 kg were the heaviest terrestrial animals. The Blue Whale at 100,000 kg is the biggest animal ever to have existed


Chordates l.jpg
Chordates

  • Chordates have a notochord and a dorsal, hollow nerve cord

  • Vertebrates are a subphylum of the phylum Chordata

  • Chordates are bilaterian animals that belong to the clade of animals known as Deuterostomia

  • Two groups of invertebrate deuterostomes, the urochordates and cephalochordates

    • Are more closely related to vertebrates than to invertebrates


A hypothetical phylogeny of chordates l.jpg

Chordates

Craniates

Vertebrates

Gnathostomes

Osteichthyans

Lobe-fins

Tetrapods

Amniotes

Echinodermata(sister group to chordates)

Chondrichthyes(sharks, rays, chimaeras)

Cephalaspidomorphi(lampreys)

Amphibia(frogs, salamanders)

Cephalochordata(lancelets)

Reptilia(turtles, snakes,crocodiles, birds)

Actinopterygii(ray-finned fishes)

Urochordata(tunicates)

Actinistia(coelacanths)

Dipnoi(lungfishes)

Myxini(hagfishes)

Mammalia(mammals)

Milk

Amniotic egg

Legs

Lobed fins

Lungs or lung derivatives

Jaws, mineralized skeleton

Vertebral column

Head

Brain

Notochord

Ancestral deuterostome

A hypothetical phylogeny of chordates


Derived characters of chordates l.jpg

Dorsal,hollownerve cord

Brain

Notochord

Musclesegments

Mouth

Anus

Pharyngealslits or clefts

Muscular,post-anal tail

Derived Characters of Chordates

  • All chordates share a set of derived characters

    • Although some species possess some of these traits only during embryonic development

1. Notochord

2. Dorsal, hollow nerve cord

3.Pharyngeal slits

4. Muscular post-anal tail


Notochord l.jpg
Notochord

  • The notochord

    • Is a longitudinal, flexible rod located between the digestive tube and the nerve cord

    • 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


Dorsal hollow nerve cord l.jpg
Dorsal, Hollow Nerve Cord

  • The nerve cord of a chordate embryo

    • Develops into the central nervous system: the brain and the spinal cord


Pharyngeal slits or clefts l.jpg
Pharyngeal Slits or Clefts

  • In most chordates, grooves in the pharynx called pharyngeal clefts develop into slits that open to the outside of the body

  • These pharyngeal slits

    • Function as suspension-feeding structures in many invertebrate chordates

    • Are modified for gas exchange in aquatic vertebrates

    • Develop into parts of the ear, head, and neck in terrestrial vertebrates


Muscular post anal tail l.jpg
Muscular, Post-Anal Tail

  • Chordates have a tail extending posterior to the anus

    • Although in many species it is lost during embryonic development

  • The chordate tail contains skeletal elements and muscles

    • And it provides much of the propelling force in many aquatic species


Tunicates subphylum urochordata l.jpg

Incurrentsiphonto mouth

Notochord

Excurrentsiphon

Dorsal, hollownerve cord

Excurrent siphon

Tail

Excurrent siphon

Atrium

Musclesegments

Pharynxwith numerousslits

Incurrentsiphon

Intestine

Anus

Stomach

Intestine

Tunic

Atrium

Esophagus

Stomach

Pharynx with slits

(b) In the adult, prominent pharyngeal slits function in suspension feeding, but other chordate characters are not obvious.

(a) An adult tunicate, or sea squirt, is a sessile animal (photo is approximately life-sized).

(c) A tunicate larva is a free-swimming butnonfeeding “tadpole” in which all fourchief characters of chordates are evident.

Tunicates (subphylum Urochordata)

  • Marine suspension feeders commonly called sea squirts

  • Tunicates most resemble chordates during their larval stage which may be as brief as a few minutes

  • As an adult a tunicate draws in water through an incurrent siphon, filtering food particles


Lancelets subphylum cephalochordata l.jpg

Tentacle

2 cm

Mouth

Pharyngeal slits

Atrium

Notochord

Digestive tract

Atriopore

Dorsal, hollownerve cord

Segmentalmuscles

Anus

Tail

Lancelets (subphylum Cephalochordata)

  • Named for their bladelike shape

  • Lancelets are marine suspension feeders that retain the characteristics of the chordate body plan as adults


Craniates l.jpg
Craniates

  • 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 common characteristics

    • A skull, brain, eyes, and other sensory organs


Neural crest l.jpg

Neuraltube

Neuralcrest

Dorsal edgesof neural plate

Ectoderm

Ectoderm

(a) The neural crest consists of bilateral bands of cells near the margins of the embryonic folds that form the neural tube.

(b) Neural crest cells migrate todistant sites in the embryo.

Migrating neuralcrest cells

Notochord

Neural crest

  • Unique to craniates, the neural crest, a collection of cells that appears near the dorsal margins of the closing neural tube in an embryo


Neural crest cells l.jpg

(c) The cells give rise to some of the anatomical structuresunique to vertebrates, including some of the bones and cartilage of the skull.

Neural crest cells

  • Give rise to a variety of structures, including some of the bones and cartilage of the skull


The origin of craniates l.jpg

5 mm

(a)Haikouella. Discovered in 1999 in southern China, Haikouella had eyes and a brain but lacked a skull, a derived trait of craniates.

(b) Haikouichthys.Haikouichthys had a skull and thus is considered a true craniate.

The Origin of Craniates

  • Craniates evolved at least 530 million years ago during the Cambrian explosion

  • The most primitive of the fossils are those of the 3-cm-long Haikouella

In other Cambrian rocks paleontologists have found fossils of even more advanced chordates, such as Haikouichthys


Hagfishes l.jpg

Slime glands

Hagfishes

  • The least derived craniate lineage that still survives is class Myxini, the hagfishes

  • Hagfishes are jawless marine craniates

    • That have a cartilaginous skull and axial rod of cartilage derived from the notochord

    • They lack vertebrae


Origin of vertebrates l.jpg
Origin of Vertebrates

  • Vertebrates are craniates that have a backbone

  • During the Cambrian period a lineage of craniates evolved into vertebrates

  • Derived Characters of Vertebrates

    • Vertebrae enclosing a spinal cord

    • An elaborate skull

    • Fin rays, in aquatic forms


Lampreys class cephalaspidomorphi l.jpg
Lampreys (Class Cephalaspidomorphi)

  • Represent the oldest living lineage of vertebrates

  • Have cartilaginous segments surrounding the notochord and arching partly over the nerve cord

  • Are jawless vertebrates

  • Inhabit various marine and freshwater habitats


Fossils of early vertebrates l.jpg

Dorsal viewof head

Dentalelements

Fossils of Early Vertebrates

  • Conodonts were the first vertebrates with mineralized skeletal elements in their mouth and pharynx


Origins of bone and teeth l.jpg
Origins of Bone and Teeth

  • Mineralization appears to have originated with vertebrate mouthparts

  • The vertebrate endoskeleton became fully mineralized much later


Gnathostomes l.jpg

Gill slits

Cranium

Mouth

Skeletal rods

Gnathostomes

  • Are vertebrates that have jaws

  • Today, jawless vertebrates are far outnumbered by those with jaws

  • Gnathostome characteristics

    • Jaws that evolved from skeletal supports of the pharyngeal slits.

    • Enhanced sensory systems, including the lateral line system

    • An extensively mineralized endoskeleton

    • Paired appendages


Chondrichthyans sharks rays and their relatives l.jpg
Chondrichthyans (Sharks, Rays, and Their Relatives)

  • Members of class Chondrichthyes

    • Have a skeleton that is composed primarily of cartilage

  • The cartilaginous skeleton

    • Evolved secondarily from an ancestral mineralized skeleton


Sharks and rays l.jpg

Blacktip reef shark (Carcharhinus melanopterus).Fast swimmers with acute senses, sharks have paired pectoral and pelvic fins.

Pelvic fins

Pectoral fins

Southern stingray (Dasyatis americana).Most rays are flattened bottom-dwellers thatcrush molluscs and crustaceans for food. Some rays cruise in open water and scoop food into their gaping mouth.

Sharks and Rays

  • The largest and most diverse subclass of Chondrichthyes includes the sharks and rays

  • Most sharks have a streamlined body and are swift swimmers and have acute senses


Ratfish l.jpg

Spotted ratfish(Hydrolagus colliei). Ratfishes, typically live at depths greaterthan 80 m and feed on shrimps, molluscs, and sea urchins. Some species have a poisonous spine at the front of their dorsal fin.

Ratfish

  • Another subclass is composed of a few dozen species of ratfishes


Ray finned fishes and lobe fins l.jpg
Ray-Finned Fishes and Lobe-Fins

  • The vast majority of vertebrates belong to a clade of gnathostomes called Osteichthyes

  • Nearly all living osteichthyans have a bony endoskeleton

  • Aquatic osteichthyans

    • Are the vertebrates we informally call fishes

    • Control their buoyancy with an air sac known as a swim bladder


Fish anatomy l.jpg

Adipose fin(characteristic oftrout)

Dorsal fin

Caudal fin

Swim bladder

Spinal cord

Brain

Nostril

Cut edge of operculum

Anal fin

Gills

Anus

Gonad

Liver

Heart

Lateral line

Stomach

Urinary bladder

Kidney

Intestine

Pelvic fin

Fish anatomy

  • Fishes breathe by drawing water over four or five pairs of gills

    • Located in chambers covered by a protective bony flap called the operculum


Ray finned fishes class actinopterygii l.jpg

(a) Yellowfin tuna (Thunnus albacares), a fast-swimming, schooling fish that is an important commercial fish worldwide

(b) Clownfish (Amphiprion ocellaris), a mutualistic symbiont of sea anemones

(c) Sea horse (Hippocampus ramulosus), unusual in the animal kingdom in that the male carries the young during their embryonic development

(d) Fine-spotted moray eel (Gymnothorax dovii), a predator that ambushes prey from crevices in its coral reef habitat

Ray-Finned Fishes (Class Actinopterygii)

Includes nearly all the familiar aquatic osteichthyans.

The fins, supported by long, flexible rays are modified for maneuvering, defense, and other functions.


Lobe fins class sarcopterygii l.jpg
Lobe-Fins (Class Sarcopterygii)

  • Have muscular and pectoral fins

  • Include coelacanths, lungfishes, and tetrapods


Tetrapods l.jpg
Tetrapods

  • Are gnathostomes that have limbs and feet

  • One of the most significant events in vertebrate history was when the fins of some lobe-fins evolved into the limbs and feet of tetrapods

  • Tetrapods have some specific adaptations

    • Four limbs and feet with digits

    • Ears for detecting airborne sounds


The origin of tetrapods l.jpg

Bonessupportinggills

Tetrapodlimbskeleton

The Origin of Tetrapods

  • In one lineage of lobe-fins

    • The fins became progressively more limb-like while the rest of the body retained adaptations for aquatic life


Origin of tetrapods l.jpg

Millions of years ago

420

370

340

310

295

280

265

415

400

385

355

325

Silurian

Devonian

Carboniferous

Permian

To present

Paleozoic

Ray-finned fishes

Coelacanths

Lungfishes

Eusthenopteron

Panderichthys

Elginerpeton

Metaxygnathus

Acanthostega

lchthyostega

Hynerpeton

Greerpeton

Amphibians

Amniotes

Origin of Tetrapods


Amphibians l.jpg

The tadpole is an

aquatic herbivore

With a fishlike

tail and internal

gills.

The male grasps the female, stimulating her to release eggs. The eggs are laid and fertilized in water. They have a jelly coat but lack a shell and would desiccate in air.

During metamorphosis, the gills and tail are resorbed, andwalking legs develop.

Amphibians

  • Class Amphibia is represented by about 4,800 species of organisms

  • Most amphibians have moist skin that complements the lungs in gas exchange

  • Amphibian means “two lives” (a reference to the metamorphosis of an aquatic larva into a terrestrial adult)



Order urodela l.jpg

Order Urodela. Urodeles (salamanders) retain their tail as adults.

Order Urodela

  • Includes salamanders, which have tails


Order anura l.jpg

Order Anura. Anurans, such as this poison arrow frog, lack a tail as adults.

Order Anura

  • Includes frogs and toads, which lack tails


Order apoda l.jpg

Order Apoda. Apodans, or caecilians, are legless, mainly burrowing amphibians.

Order Apoda

  • Includes caecilians, which are legless and resemble worms


Amniotes l.jpg
Amniotes

  • Amniotes are a group of tetrapods

    • Whose living members are the reptiles, including birds, and the mammals

    • that have a terrestrially adapted egg

    • the amniotic egg contains specialized membranes that protect the embryo

    • Amniotes also have other terrestrial adaptations such as relatively impermeable skin and the ability to use the rib cage to ventilate the lungs

    • Early amniotes appeared in the Carboniferous period


A phylogeny of amniotes l.jpg

dinosaurs other

Saurischian

than birds

Ornithischiandinosaurs

Crocodilians

Ichthyosaurs

Plesiosaurs

Squamates

Mammals

Pterosaurs

Parareptiles

Tuatara

Turtles

Birds

Saurischians

Dinosaurs

Lepidosaurs

Archosaurs

Synapsids

Diapsids

Reptiles

Ancestralamniote

A phylogeny of amniotes


Slide40 l.jpg

Traditionally, lizards, snakes, and crocs are classified together in the Class Reptilia with birds in a separate class (Aves)

But crocodiles may actually be more closely related to birds than to lizards and snakes


The extraembryonic membranes l.jpg

Chorion. together in the Class Reptilia with birds in a separate class (Aves) The chorion and the membrane of the allantois exchange gases between the embryo and the air. Oxygen and carbon dioxide diffuse freely across the shell.

Allantois. The allantois is a disposal

sac for certain metabolic wastes pro-

duced by the embryo. The membrane

of the allantois also functions with

the chorion as a respiratory organ.

Extraembryonic membranes

Yolk sac. The yolk sac contains the yolk, a stockpile of nutrients. Blood vessels in the yolk sac membrane transport nutrients from the yolk into the embryo. Other nutrients are stored in the albumen (“egg white”).

Amnion. The amnion protectsthe embryo in a fluid-filled cavity that cushions againstmechanical shock.

Embryo

Amniotic cavitywith amniotic fluid

Yolk (nutrients)

Albumen

Shell

The extraembryonic membranes


Reptiles l.jpg
Reptiles together in the Class Reptilia with birds in a separate class (Aves)

  • The reptile clade includes

    • The tuatara, lizards, snakes, turtles, crocodilians, birds, and the extinct dinosaurs

  • Reptiles

    • Have scales that create a waterproof barrier

    • 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)

Hatching Komodo dragon


The origin and evolutionary radiation of reptiles l.jpg
The Origin and Evolutionary Radiation of Reptiles together in the Class Reptilia with birds in a separate class (Aves)

  • The oldest reptilian fossils date to about 300 million years ago

  • The first major group of reptiles to emerge were the parareptiles, which were mostly large, stocky herbivores

  • As parareptiles were dwindling the diapsids were diversifying

  • The diapsids are composed of two main lineages

    • The lepidosaurs and the archosaurs

    • Snakes and lizards are surviving forms of lepidosaurs

    • Crocs and gators are an archosaur lineage


Dinosaurs l.jpg

Deinonychus together in the Class Reptilia with birds in a separate class (Aves)

Dinosaurs

Diversified into a vast range of shapes and sizes

Included the long-necked giants called the theropods

  • Traditionally, dinosaurs were considered slow, sluggish creatures

    • But fossil discoveries and research have led to the conclusion that dinosaurs were agile and fast moving

  • Paleontologists have also discovered signs of parental care among dinosaurs

Nesting Oviraptor and eggs


Lepidosaurs l.jpg

Tuatara together in the Class Reptilia with birds in a separate class (Aves)(Sphenodon punctatus)

Lepidosaurs

  • One surviving lineage of lepidosaurs is represented by two species of lizard-like reptiles called tuatara

Found only in New Zealand…endangered


Squamates l.jpg

Australian thorny devil lizard together in the Class Reptilia with birds in a separate class (Aves)(Moloch horridus)

Squamates

  • The other major living lineage of lepidosaurs

    • Are the squamates, the lizards and snakes

  • Lizards are the most numerous and diverse reptiles, apart from birds


Snakes l.jpg

Wagler’s pit viper together in the Class Reptilia with birds in a separate class (Aves)(Tropidolaemus wagleri)

Snakes

  • Snakes are legless lepidosaurs that evolved from lizards


Turtles l.jpg

Eastern box turtle together in the Class Reptilia with birds in a separate class (Aves)(Terrapene carolina carolina)

Turtles

  • Some turtles have adapted to deserts and others live entirely in ponds and rivers

  • All turtles have a boxlike shell

    • Made of upper and lower shields that are fused to the vertebrae, clavicles, and ribs


Alligators and crocodiles l.jpg

American alligator together in the Class Reptilia with birds in a separate class (Aves)(Alligator mississipiensis)

Alligators and Crocodiles

  • Crocodilians

    • Belong to an archosaur lineage that dates back to the late Triassic


Evolution of birds l.jpg
Evolution of birds together in the Class Reptilia with birds in a separate class (Aves)


Birds l.jpg

Finger 1 together in the Class Reptilia with birds in a separate class (Aves)

(b) Bone structure

Palm

(a) wing

Finger 2

Forearm

Wrist

Finger 3

Shaft

Vane

Barb

Shaft

Barbule

Hook

(c) Feather structure

Birds

  • Birds are archosaurs

    • But almost every feature of their reptilian anatomy has undergone modification in their adaptation to flight

  • Many of the characters of birds are adaptations that facilitate flight

    • A bird’s most obvious adaptations for flight are its wings and feathers


The origin of birds l.jpg

Wing claw together in the Class Reptilia with birds in a separate class (Aves)

Toothed beak

Airfoil wing with contour feathers

Long tail with many vertebrae

The Origin of Birds

  • Birds probably descended from theropods (small, carnivorous dinosaurs)

  • By 150 million years ago feathered theropods had evolved into birds

  • Archaeopteryx


The ratites order struthioniformes l.jpg

Emu. together in the Class Reptilia with birds in a separate class (Aves) This ratite lives in Australia.

The ratites, order Struthioniformes

  • Are all flightless


Flying birds l.jpg

Mallards. together in the Class Reptilia with birds in a separate class (Aves) Like many bird species, the mallard exhibits pronounced color differences between the sexes.

Laysan albatrosses. Like most birds, Laysan albatrosses have specific mating behaviors, such as this courtship ritual.

Barn swallows. The barn swallow is a member of the order Passeriformes. Species in this order are called perching birds because the toes of their feet can lock around a branch or wire, enabling the bird to rest in place for long periods.

Flying birds

  • The demands of flight have rendered the general body form of many flying birds similar to one another


Foot structure l.jpg

Raptor together in the Class Reptilia with birds in a separate class (Aves)(such as a bald eagle)

Grasping bird (such as a woodpecker)

Swimming bird(such as a duck)

Perching bird (such as a cardinal)

Foot Structure

  • Foot structure in bird feet shows considerable variation


Mammals class mammalia l.jpg
Mammals, class Mammalia together in the Class Reptilia with birds in a separate class (Aves)

  • Represented by more than 5,000 species

  • Derived Characters of Mammals

    • Mammary glands, which produce milk

    • Hair is another mammalian characteristic

    • Mammals generally have a larger brain than other vertebrates of equivalent size


Early evolution of mammals l.jpg

Jaw joint together in the Class Reptilia with birds in a separate class (Aves)

Jaw joint

Dimetrodon

Morganucodon

Key

Dentary

Angular

Squamosal

Eardrum

Middle ear

Inner ear

Articular

Quadrate

Inner ear

Eardrum

Stapes

(a) The lower jaw of Dimetrodon is composed of several fused bones; two small bones, the quadrate and articular, form part of the jaw joint. In Morganucodon, the lower jaw is reduced to a single bone, the dentary, and the location of the jaw joint has shifted.

Middle ear

Stapes

Incus (evolvedfrom quadrate)

Sound

Sound

Malleus (evolvedfrom articular)

Morganucodon

Dimetrodon

(b) During the evolutionary remodeling of the mammalian skull, the quadrate and articular bones became incorporated into the middle ear as two of the three bones that transmit sound from the eardrum to the inner ear. The steps in this evolutionary remodeling are evident in a succession of fossils.

Early Evolution of Mammals

  • Mammals evolved from synapsids in the late Triassic period

  • The jaw was remodeled during the evolution of mammals from nonmammalian synapsids

    • And two of the bones that formerly made of the jaw joint were incorporated into the mammalian middle ear

  • Living lineages of mammals originated in the Jurassic but did not undergo a significant adaptive radiation until after the Cretaceous


Monotremes l.jpg
Monotremes together in the Class Reptilia with birds in a separate class (Aves)

Are a small group of egg-laying mammals consisting of echidnas and the platypus

Mammalian egg


Marsupials l.jpg

A young brushtail possum. together in the Class Reptilia with birds in a separate class (Aves) The young of marsupials are born very early in their development. They finish their growth while nursing from a nipple (in their mother’s pouch in most species).

Marsupials

  • Marsupials include opossums, kangaroos, and koalas

  • A marsupial is born very early in its development and completes its embryonic development while nursing within a maternal pouch called a marsupium


Marsupials60 l.jpg

Long-nosed bandicoot. together in the Class Reptilia with birds in a separate class (Aves) Most bandicoots are diggers and burrowers that eat mainly insects but also some small vertebrates andplant material. Their rear-opening pouch helps protect the young from dirt as the mother digs. Other marsupials, such as kangaroos, have a pouch that opens to the front.

Marsupials

  • In some species of marsupials, such as the bandicoot

    • The marsupium opens to the rear of the mother’s body as opposed to the front, as in other marsupials


Convergent evolution l.jpg

Marsupial mammals together in the Class Reptilia with birds in a separate class (Aves)

Eutherian mammals

Plantigale

Deer mouse

Mole

Marsupial mole

Sugar glider

Flying squirrel

Wombat

Woodchuck

Wolverine

Tasmanian devil

Patagonian cavy

Kangaroo

Convergent evolution

  • In Australia, convergent evolution has resulted in a diversity of marsupials that resemble eutherians in other parts of the world


Eutherians placental mammals l.jpg
Eutherians (Placental Mammals) together in the Class Reptilia with birds in a separate class (Aves)

  • Have a longer period of pregnancy compared to marsupials.

  • Young eutherians complete their embryonic development within a uterus, joined to the mother by the placenta.


Phylogenetic relationships of mammals l.jpg

This clade of eutherians evolved together in the Class Reptilia with birds in a separate class (Aves)in Africa when the continent was isolated from other landmasses. It includesEarth’s largest living land animal (the African elephant), as well as species that weighless than 10 g.

This diverse clade includes terrestrial and marine mammals as well as bats,the only flying mammals. A growingbody of evidence, including Eocene fossils of whales with feet,supports putting whales inthe same order (Cetartiodactyla)

as pigs, cows, and hippos.

This is the largest eutherian clade. It includes the rodents, which make up the largest mammalian order by far, with about 1,770 species. Humansbelong to the order Primates.

All members of this clade, which underwent an adaptive radiation in South America, belong to the order Xenarthra. One species, the nine-banded armadillo, is found in the southern United States.

Proboscidea Sirenia

Tubulidentata Hyracoidea

Afrosoricida (golden moles and tenrecs)

Macroscelidea (elephant shrews)

Rodentia

Lagomorpha

Primates

Dermoptera (flying lemurs)

Scandentia (tree shrews)

Carnivora

Cetartiodactyla

Perissodactyla

Chiroptera

Eulipotyphla

Pholidota (pangolins)

Monotremata

Marsupialia

Xenarthra

Monotremes

Marsupials

Eutherians

Possible phylogenetic tree of mammals.All 20 extant orders of mammals are listed at the top of the tree. Boldfaced orders are explored on the facing page.

Ancestral mammal

Phylogenetic relationships of mammals


The major eutherian orders l.jpg

MAIN together in the Class Reptilia with birds in a separate class (Aves)CHARACTERISTICS

ORDERS

AND EXAMPLES

ORDERS

AND EXAMPLES

MAIN CHARACTERISTICS

Embryo completes development in pouch on mother

Marsupialia

Kangaroos,

opossums,

koalas

Lay eggs; nonipples; young suck milk fromfur of mother

MonotremataPlatypuses, echidnas

Echidna

Koala

Tubulidentata

Aardvark

Teeth consisting of many thin tubes cemented together; eats ants and termites

ProboscideaElephants

Long, musculartrunk; thick, loose skin; upper incisors elongated as tusks

African elephant

Aardvark

Hyracoidea

Hyraxes

Short legs; stumpy tail; herbivorous; complex, multichambered

stomach

Aquatic; finlikeforelimbs and no hind limbs; herbivorous

SireniaManatees,dugongs

Rock hyrax

Manatee

Chisel-like, continuously growing incisors worn down by gnawing;herbivorous

Rodentia

Squirrels,

beavers, rats,

porcupines,

mice  

XenarthraSloths, anteaters,armadillos

Reduced teeth orno teeth; herbivorous(sloths) or carnivorous (anteaters, armadillos)

Red squirrel

Tamandua

Primates

Lemurs,

monkeys,

apes,

humans

Opposable thumbs; forward-facing eyes; well-developed cerebral cortex; omnivorous

Lagomorpha Rabbits, hares, picas

Chisel-like incisors; hind legs longer than forelegs and adapted for running and jumping

Golden lion tamarin

Jackrabbit

Perissodactyla

Horses,

zebras, tapirs,

rhinoceroses

Hooves with an odd number of toeson each foot; herbivorous

Sharp, pointed canineteeth and molars for shearing; carnivorous

CarnivoraDogs, wolves,bears, cats, weasels, otters,

seals, walruses

Indian rhinoceros

Coyote

Chiroptera

Bats

Adapted for flight; broad skinfold that extends from elongated fingers to body and legs; carnivorous or herbivorous

Hooves with an even number of toes on each foot; herbivorous

CetartiodactylaArtiodactylsSheep, pigs cattle, deer,giraffes

Frog-eating bat

Bighorn sheep

Aquatic; streamlinedbody; paddle-like forelimbs and no hind limbs; thicklayer of insulating blubber; carnivorous

Eulipotyphla

“Core insecti-

vores”: some

moles, some

shrews

Diet consists mainly of insects and other small invertebrates

CetaceansWhales,dolphins,porpoises

Star-nosed mole

Pacific white-sided porpoise

The major eutherian orders


Primates l.jpg
Primates together in the Class Reptilia with birds in a separate class (Aves)

  • Order Primates include

    • Lemurs, tarsiers, monkeys, and apes

  • Derived Characters of Primates

    • A large brain and short jaws

    • Forward-looking eyes close together on the face, providing depth perception

    • Well-developed parental care and complex social behavior

    • A fully opposable thumb

    • Most primates have hands and feet adapted for grasping


Living primates l.jpg
Living Primates together in the Class Reptilia with birds in a separate class (Aves)

  • There are three main groups of living primates

    • The lemurs of Madagascar and the lorises and pottos of tropical Africa and southern Asia

    • The tarsiers of Southeast Asia

    • The anthropoids, which include monkeys and hominids worldwide


The primate family tree l.jpg

Anthropoids together in the Class Reptilia with birds in a separate class (Aves)

0

Chim-panzees

Gorillas

Gibbons

Tarsiers

Humans

Orangutans

Old World monkeys

New World monkeys

Lemurs, lorises, and pottos

10

20

Millions of years ago

30

40

50

Ancestral primate

60

The Primate Family Tree


Monkeys l.jpg

(a) together in the Class Reptilia with birds in a separate class (Aves) New World monkeys, such as spider monkeys (shown here), squirrel monkeys, and capuchins, have a prehensile tail and nostrils that open to the sides.

(b) Old World monkeys lack a prehensile tail, and their nostrils open downward. This group includes macaques (shown here), mandrills, baboons, and rhesus monkeys.

Monkeys

  • The first monkeys evolved in the Old World (Africa and Asia)

  • Monkeys first appeared in the New World (South America) during the Oligocene

  • New World and Old World monkeys

    • Underwent separate adaptive radiations during their many millions of years of separation


Hominoids l.jpg

(a) together in the Class Reptilia with birds in a separate class (Aves) Gibbons, such as this Muller's gibbon, are found only in southeastern Asia. Their very long arms and fingers are adaptations for brachiation.

(b) Orangutans are shy, solitary apes that live in the rain forests of Sumatra and Borneo. They spend most of their time in trees; note the foot adapted for grasping and the opposable thumb.

(c) Gorillas are the largest apes: some males are almost 2 m tall and weigh about 200 kg. Found only in Africa, these herbivores usually live in groups of up to about 20 individuals.

(e) Bonobos are closely related to chimpanzees but are smaller. They survive today only in the African nation of Congo.

(d) Chimpanzees live in tropical Africa. They feed and sleep in trees but also spend a great deal of time on the ground. Chimpanzees are intelligent, communicative, and social.

Hominoids

  • Hominoids-consist of primates informally called apes

  • Hominoids diverged from Old World monkeys about 20–25 million years ago


Humans l.jpg
Humans together in the Class Reptilia with birds in a separate class (Aves)

  • Humans are bipedal hominoids with a large brain

  • Homo sapiens is about 160,000 years old (which is very young considering that life has existed on Earth for at least 3.5 billion years)

  • A number of characters distinguish humans from other hominoids

    • Upright posture and bipedal locomotion

    • Larger brains

    • Language capabilities

    • Symbolic thought

    • The manufacture and use of complex tools

    • Shortened jaw


The earliest humans l.jpg
The Earliest Humans together in the Class Reptilia with birds in a separate class (Aves)

  • The study of human origins is known as paleoanthropology

  • Paleoanthropologists have discovered fossils of approximately 20 species of extinct hominoids

    • That are more closely related to humans than to chimpanzees


Hominids l.jpg

Paranthropus together in the Class Reptilia with birds in a separate class (Aves)robustus

Homoneanderthalensis

Homosapiens

0

Paranthropusboisei

Homoergaster

?

0.5

1.0

Australopithecusafricanus

1.5

2.0

Kenyanthropusplatyops

2.5

Australopithecusgarhi

Homoerectus

3.0

Millions of years ago

Australopithecusanamensis

3.5

Homohabilis

Homorudolfensis

4.0

4.5

Ardipithecusramidus

Australopithecusafarensis

5.0

5.5

Orrorin tugenensis

6.0

6.5

Sahelanthropustchadensis

7.0

Hominids


Early hominids l.jpg
Early Hominids together in the Class Reptilia with birds in a separate class (Aves)

  • Early hominids

    • Had a small brain, but probably walked upright, exhibiting mosaic evolution

    • Originated in Africa approximately 6–7 million years ago

  • Two common misconceptions of early hominids include

    • Thinking of them as chimpanzees

    • Imagining human evolution as a ladder leading directly to Homo sapiens


Australopiths l.jpg

(b) together in the Class Reptilia with birds in a separate class (Aves) The Laetoli footprints, more than 3.5 million years old, confirm that upright posture evolved quite early in hominid history.

(a) Lucy, a 3.24-million-year-old skeleton, represents the hominid species Australopithecus afarensis.

(c) An artist’s reconstruction of what A. afarensis may have looked like.

Australopiths

  • Australopiths are hominids that lived between 4 and 2 million years ago

  • Some species walked fully erect and had human-like hands and teeth.


Hominid evolution l.jpg
Hominid evolution together in the Class Reptilia with birds in a separate class (Aves)

  • Bipedalism: Hominids began to walk long distances on two legs about 1.9 million years ago

  • Tool use: The oldest evidence of tool use—cut marks on animal bones is 2.5 million years old


Early homo l.jpg
Early together in the Class Reptilia with birds in a separate class (Aves)Homo

  • The earliest fossils that paleoanthropologists place in our genus Homo

    • Are those of the species Homo habilis, ranging in age from about 2.4 to 1.6 million years

  • Stone tools have been found with H. habilis

    • Giving this species its name, which means “handy man”


Slide77 l.jpg
Homo together in the Class Reptilia with birds in a separate class (Aves)

  • Homoergaster

    • Was the first fully bipedal, large-brained hominid

    • Existed between 1.9 and 1.6 million years

  • Homo erectus

    • Originated in Africa approximately 1.8 million years ago

    • Was the first hominid to leave Africa

  • Neanderthals (Homo neanderthalensis)

    • Lived in Europe and the Near East from 200,000 to 30,000 years ago

    • Were large, thick-browed hominids

    • Became extinct a few thousand years after the arrival of Homo sapiens in Europe


Homo sapiens l.jpg
Homo sapiens together in the Class Reptilia with birds in a separate class (Aves)

  • Appeared in Africa at least 160,000 years ago

  • The oldest fossils of Homo sapiens outside Africa

    • Date back about 50,000 years ago

  • The rapid expansion of our species

    • May have been preceded by changes to the brain that made symbolic thought and other cognitive innovations possible


ad