Chapter 19 The Evolution of Vertebrate Diversity 19 - Vertebrate... · 19.1 Derived characters...

Copyright © 2009 Pearson Education, Inc.

PowerPoint Lectures for

Biology: Concepts & Connections, Sixth Edition

Campbell, Reece, Taylor, Simon, and Dickey

Chapter 19 The Evolution of Vertebrate

Diversity

Lecture by Joan Sharp

The duck-billed platypus is a strange animal and hard to classify

– It has a furry body, bill, and webbed feet, and it lays eggs

– It has mammary glands that produce milk for its young

– The platypus bill is not similar to that of a duck, but instead is a sensory organ for locating food underwater

– A large portion of the platypus brain is devoted to processing sensory information from its bill

The duck-billed platypus is a monotreme, a small group of egg-laying mammals

Introduction: What Am I?


VERTEBRATE EVOLUTION AND DIVERSITY


A phylogenetic tree for chordates is based on a sequence of derived characters

19.1 Derived characters define the major clades of chordates


Ancestralchordate

Brain

Head

Vertebral column

Jaws

Lungs or lung derivatives

Lobed fins

Legs

Amniotic egg

Milk

Mammals

Reptiles

Amphibians

Lobe-fins

Ray-finned fishes

Sharks, rays

Lampreys

Hagfishes

Lancelets

TunicatesC

ran

iate

s

Am

nio

tes

Hagfishes and lampreys are craniates but lack hinged jaws and paired fins

– In hagfishes, the notochord is the body’s main support in the adult

– Lampreys have a supportive notochord but also have rudimentary vertebral structures, making them vertebrates

19.2 Hagfishes and lampreys lack hinged jaws


Hagfishes are deep-sea scavengers that produce slime as an antipredator defense

Lampreys are parasites that penetrate the sides of fishes with their rasping tongues

– Larval lampreys resemble lancelets

– They are suspension feeders that live in freshwater streams, where they feed buried in sediment


19.2 Hagfishes and lampreys lack hinged jaws

Slimeglands

Novel vertebrate features arose 470 million years ago

– Paired fins and tail

– Hinged jaws

Where did jaws come from?

– They arose as modifications of skeletal supports of the anterior pharyngeal gill slits (originally used for trapping suspended food particles)

– The remaining gill slits remained as sites of gas exchange

19.3 Jawed vertebrates with gills and paired fins include sharks, ray-finned fishes, and lobe-finned fishes


Gillslits

Skeletalrods

Skull

Mouth

Hinged jaw

There are three lineages of jawed fishes

– Class Chondrichthyes includes sharks and rays

– Ray-finned fishes and lobe-fins have lungs (or lung derivatives)

– Lobe-finned fishes have muscular fins supported by stout bones



Chondrichthyans

– Sharks and rays have a flexible skeleton made of cartilage

– Most sharks are fast-swimming predators, with sharp vision and a keen sense of smell

– Electrosensors on their heads and a lateral line system aid them in locating prey

– Most rays are adapted for life on the bottom, with dorsoventrally flattened bodies and eyes on the top of their heads





Video: Seahorse Camouflage

Video: Coral Reef

Video: Clownfish and Anemone

Video: Manta Ray

Video: Shark Eating a Seal

19_03ESeaHorses_SV.mpg

19_03ECoralReef_SV.mpg

19_03EClownfishAnemone_SV.mpg

19_03CMantaRay_SV.mpg

19_03BSharkEatSeal_SV.mpg

Gillopenings

Ray-finned fishes have

– Internal skeleton reinforced with a hard matrix of CaPO3

– Flattened scales covered with mucus

– Operculum to move water over the gills

– Buoyant swim bladder (derived from an ancestral lung)

The diverse group of ray-finned fishes includes 27,000 species



GillsBony skeleton Dorsal fin

Anal fin

Swim bladderPelvic finHeartPectoral fin

Operculum

Rainbow trout,a ray-fin

Lobe-fins

– Lobe-fins have muscular pelvic and pectoral fins, supported by rod-shaped bones

– Three lineages of lobe-fins survive

– Coelacanths

– Lungfishes

– Tetrapods



During the late Devonian, a line of lobe-fin fishes gave rise to tetrapods, jawed vertebrates with limbs and feet

19.4 New fossil discoveries are filling in the gaps of tetrapod evolution


Devonian Carboniferous

Ray-finned fish

Coelocanth

Lungfish

Eusthenopteron

Pandericthys

Tiktaalik

Acanthostega

Ichthyostega

Tetrapod with no gills,

limbs better-adapted

for bearing weight

Modern

amphibians

Reptiles (including birds) and mammalsTime known

to exist

420 400 380 360 340 320 300 280 260 0

Millions of years ago


Ray-finned fish

Coelocanth

Lungfish

Time knownto exist

420 400 380 360 340 320 300 280 260 0



Time knownto exist

Eusthenopteron

Pandericthys

Tiktaalik

Acanthostega

Ichthyostega

Tetrapod with no gills,limbs better-adapted

for bearing weight

420 400 380 360 340 320 300 280 260 0



420 400 380 360 340 320 300 280 260 0


Modern

amphibians

Reptiles (including birds) and mammalsTime knownto exist

Bonessupportinggills

Tetrapodlimbskeleton

Amphibians were the first tetrapods able to move on land

– Most amphibians have tadpole larvae

This group includes frogs, salamanders, and caecilians

– Salamanders walk on land with a side-to-side bending

– Frogs hop with powerful hind legs

– Caecilians are blind and legless, burrowing in moist tropical soil

19.5 Amphibians are tetrapods—vertebrates with two pairs of limbs


Reptiles (including birds) and mammals are amniotes

– The major derived character of this clade is an amniotic egg with an amnion, a private pond in which the embryo develops

Amniotic reptiles include lizards, snakes, turtles, crocodilians, and birds

– Terrestrial adaptations of reptiles include scales, waterproofed with keratin

– Nonbird reptiles are ectothermic, but regulate their temperature by basking or seeking shade

19.6 Reptiles are amniotes—tetrapods with a terrestrially adapted egg



19.6 Reptiles are amniotes—tetrapods with a terrestrially adapted egg

Video: Galápagos Tortoise

Video: Galápagos Marine Iguana

Video: Snake Ritual Wrestling

19_06Tortoise_SV.mpg

19_06BMarineIguana_SV.mpg

19_06ASnakesWrestle_SV.mpg

Birds evolved from a lineage of small, two-legged dinosaurs called theropods

– Archaeopteryx is the oldest bird (150 million years old), with feathered wings

– It resembled a small bipedal dinosaur, with teeth, wing claws, and a long tail with many vertebrae

Living birds evolved from a lineage of birds that survived the Cretaceous extinctions

19.7 Birds are feathered reptiles with adaptations for flight


Video: Soaring Hawk Video: Swans Taking Flight

Video: Flapping Geese

19_07BSoaringHawk_SV.mpg

19_07BSwansTakeFlight_SV.mpg

19_07BFlappingGeese_SV.mpg

Wing claw(like dinosaur)

Feathers

Teeth(like dinosaur)

Long tail withmany vertebrae(like dinosaur)

Birds are reptiles with feathered wings, endothermic metabolism, and a number of adaptations for flight

– Loss of teeth

– Tail supported by only a few small vertebrae

– Feathers with hollow shafts

– Strong but light honeycombed bones

Flight is very costly, and birds are endotherms with a high rate of metabolism

Birds have relatively large brains and display complex behaviors


19.7 Birds are feathered reptiles with adaptations for flight

Mammals are endothermic amniotes with hair, which insulates their bodies, and mammary glands, which produce milk

– Mammalians generally have larger relative brain size than other vertebrates and a relatively long period of parental care

19.8 Mammals are amniotes that have hair and produce milk


The first true mammals arose 200 million years ago as small, nocturnal insectivores

– Marsupials diverged from eutherians (placental mammals) 180 million years ago

– They underwent an adaptive radiation following the Cretaceous extinction, giving rise to large terrestrial carnivores and herbivores, bats, and aquatic whales and porpoises



Monotremes are egg-laying mammals

– Living monotremes include the duck-billed platypus

Unlike monotremes, the embryos of marsupials and eutherians are nurtured by a placenta within the uterus

– The placenta allows nutrients from the mother’s blood to diffuse into the embryo’s blood





Video: Galápagos Sea Lion

Video: Bat Pollinating Agave Plant

Video: Bat Licking Nectar

Video: Wolves Agonistic Behavior

19_08CWolvesAgonistic_SV.mpg

19_08CSeaLion_SV.mpg

19_08CBatPollinating_SV.mpg

19_08CBatLicking_SV.mpg

Marsupials have a brief gestation

– They give birth to tiny, embryonic offspring

– The offspring complete development attached to the mother’s nipples, usually inside a pouch or marsupium



Eutherians bear fully developed live young

– They are commonly called placental mammals, because their placentas are more complex than those of marsupials



PRIMATE DIVERSITY


The mammalian order Primates includes the lemurs, tarsiers, monkeys, and apes

– Primates arose as small arboreal mammals before 65 million years ago

Many primate characters are arboreal adaptations

– Shoulder and hip joints allow climbing and brachiation

– Grasping hands and feet are highly mobile and flexible

– Sensitive hands and feet aid in manipulation

– A short snout and forward-pointing eyes enhance depth perception

19.9 The human story begins with our primate heritage


A phylogenetic tree shows that all primates are divided into three groups



Lemurs, lorises,

and pottos

Tarsiers

New World monkeys

Old World monkeys

Gibbons

Orangutans

Gorillas

Chimpanzees

Humans

0


102030405060

Ancestral

primate

An

thro

po

ids

Ho

min

oid

s (a

pe

s)



The lorises, lemurs, and pottos make up one group of primates

– 32 living species of lemur are found only in Madagascar



The tarsiers form a second group of primates

– These small, nocturnal tree-dwellers have flat faces and large eyes



The anthropoid group includes monkeys, apes, and humans

– Anthropoids have large relative brain size

– They rely more on eyesight and less on olfaction than other mammals

– Anthropoids have fully opposable thumbs

Hominoids (apes) include gibbons, orangutans, gorillas, chimpanzees (and bonobos), and humans

– Nonhuman apes have a smaller geographic range than monkeys

– Nonhuman apes live only in Africa and Southeast Asia, in tropical rain forests

Apes have relatively large brain size and flexible behavior

Gorillas, chimpanzees, and humans have a high degree of social organization

19.10 Hominoids include humans and four other groups of apes


Gibbons are the only fully arboreal apes

– They are monogamous



Video: Chimp Cracking Nut

Video: Chimp Agonistic Behavior

Video: Gibbons Brachiating

19_10DChimpCrackNut_SV.mpg

19_10DChimpAgonistic_SV.mpg

19_10AGibbonBrachiating_SV.mpg

Orangutans are shy and solitary and live in rain-forest trees and the forest floor



Gorillas, the largest of the apes, are fully terrestrial



Chimpanzees make and use tools

Humans and chimpanzees diverged from a common ancestor between 5 and 7 million years ago

– They share 99% of their genes



HOMINID EVOLUTION


The oldest possible hominid yet discovered, Sakelanthropus tchadensis, lived about 7 to 6 million years ago

The fossil record suggests that hominid diversity increased dramatically between 4 to 2 million years ago

19.11 The hominid branch of the primate tree is only a few million years old


Australopithecus

anamensis

Australopithecus

afarensis

Australopithecus

africanus

Paranthropus

boisei

Paranthropus

robustus

Homo

ergaster?

Homo

sapiens

Homo

neanderthalensis

Homo

erectus

Homo

habilisKenyanthropus

platyops

Ardipithecus

ramidus

Sahelanthropus

tchadensis

Orrorin tugenensis

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.5

5.5

5.0

4.0

6.0

7.0

6.5

Bipedalism arose 4 million years ago in the first australopiths

– A large brain evolved later

What is the evidence for this?

– Evidence from fossil trackways

– Evidence from hominid fossils

19.12 Upright posture evolved long before an enlarged brain


Homo sapiens has a brain size of around 1350 cc, triple that of australopiths

Homo habilis (2.4 million years ago) had a brain size of 500–800 cc

– Their fossils are found with stone tools

Homo ergaster (1.9–1.6 million years ago) had a brain size ranging from 850–1,100 cc

– Their fossils associated with more sophisticated stone tools

– Their long, slender legs were adapted for long-distance walking

19.13 Larger brains mark the evolution of Homo


Homo erectus, with a brain volume of around 1,000 cc, was the first hominid to leave Africa


19.13 Larger brains mark the evolution of Homo

Neanderthals lived in Europe until 30,000–40,000 years ago and were sympatric with our Cro-Magnon ancestors

– Neanderthals were muscular and robust, with a brain that was similar in size but distinct in shape to the human brain

– Neanderthals had large noses, heavy brows and cheekbones, and hunting tools made of stone and wood

19.14 Neanderthals and our human ancestors diverged half a million years ago


Did Neanderthals interbreed with Cro-Magnons?

– A 1997 analysis of mtDNA isolated from Neanderthal bones suggests that they were a distinct species from modern humans

– The last common ancestor to humans and Neanderthals lived 500,000 years ago

– There is a current project to sequence Neanderthal DNA


19.14 Neanderthals and our human ancestors diverged half a million years ago

Approximate rangeof Neanderthals

35,000 years ago

30,000–35,000 years ago

30,000 years ago

Key

Europe

Africa

Neander Valley

Original discovery

Atlantic Ocean

Black Sea

Mediterranean Sea

Analysis of mtDNA and Y chromosomes suggest that

– All living humans inherited their mtDNA from a woman who lived 160,000–200,000 years ago

– All living humans diverged from a common African ancestor

19.15 From origins in Africa, Homo sapiens spread around the world


Our species emerged from Africa in one or more waves, migrating to Asia 50–60,000 years ago and then to Europe, Southeast Asia, and Australia

The capacity for creativity and symbolic thought may have triggered human evolution


19.15 From origins in Africa, Homo sapiens spread around the world

NorthAmerica

SouthAmerica

Australia

Asia

Europe

Africa

100,000 BP

40,000 BP

50–60,000 BP

>40,000 BP(50–60,000?)

15–35,000 BP

Language is a uniquely human trait that permits the creation of human cultures

– Humans can use language in abstract ways

Linguistic ability has been linked to the human version of the FOXP2 gene

– FOXP2 (found in many vocalizing animals) codes for a transcription factor that controls the expression of many genes

– The human form of FOXP2 arose within the last 100,000 years

19.16 A genetic difference helped humans start speaking


Human skin color varies geographically, likely as a result of natural selection

Natural selection may have balanced

– Skin’s ability to block UV radiation, which degrades folate, and

– Skin’s ability to absorb UV radiation in order to synthesize vitamin D

– Folate is vital for fetal development and spermatogenesis

– Vitamin D is essential for proper bone development (especially in pregnant women and small children)

19.17 EVOLUTION CONNECTION: Human skin color reflects adaptations to varying amounts of sunlight


Introduced species are threatening Australia’s native animals

– The catlike quoll is a marsupial predator, endemic to Australia

– Quolls are dying because they feed on introduced poisonous cane toads

– Australia has moved some threatened species to uninhabited offshore islands that lack invasive species

19.18 CONNECTION: Humans threaten animal diversity by introducing non-native species


1. Describe the key derived traits of chordates and chordate taxa

2. Describe the characteristics of the following vertebrate groups: hagfishes, lampreys, chondrichthyans, ray-finned fishes, lobe-finned fishes, amphibians, reptiles, birds, and mammals

3. Describe the transitional forms of animals from fish to amphibian

You should now be able to


4. Distinguish between monotremes, marsupials, and placental mammals; note an example of each

5. Compare the three main groups of primates; list their characteristics and describe their evolutionary relationships

6. Distinguish between hominoids, hominids, australopiths, and members of the genus Homo

7. Describe the evidence that suggests when upright posture first evolved in humans



8. Describe the evolution of larger brain size in hominids

9. Describe the relationship between Neanderthals, Cro-Magnons, and modern humans

10. Explain how the FOXP2 gene may have influenced human evolution

11. Explain why skin color is not a reliable indicator of phylogenetic relationships



Chapter 19 The Evolution of Vertebrate Diversity 19 - Vertebrate... · 19.1 Derived characters...

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