BIS2C: Lecture 33: Vertebrates

Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016

Lecture 33:

Deuterostomes III: Chordates II

BIS 002C Biodiversity & the Tree of Life

Spring 2016

Prof. Jonathan Eisen

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Where we are going and where we have been…

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•Previous lecture: •32: Deuterostomes II: Chordates

•Current Lecture: •33: Deuterostomes III: Chordates II

•Next Lecture: •34: Fungi


SmartSite issues?

How are the problems with SmartSite affecting you?

A. Causing me lots of trouble

B. Causing me some trouble C. Causing me no trouble

D. Good riddance

E. Both A and D

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BIS2C Final Exam Section B

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Date & Time: Saturday, June 4, 1:00 PM – 3:00 PM

Please arrive early and bring: 1. Photo ID 2. Pen 3. #2 pencil

LAST NAMES EXAM LOCATION

A - J1100 SOCIAL

SCIENCES

K - R 1003 GEIDT

S - Z 176 Everson


Lab Practical: May 31-June 2

Do NOT enter until instructed by your TA**Please show up 10 minutes in advance of your exam**

The start time of your exam depends on where you usually attend lab. Most of you will be starting at your regular lab time, but see below for the ‘halfway’ start times.

Regular lab location Exam is in Exam starts at

3079 SLB 3079 SLB usual start time3085 SLB 3085 SLB usual start time3088 SLB 3079 SLB halfway through period3090 SLB 3085 SLB halfway through period

Regardless of when your exam will begin, do not be late as there is no way for you to make up the questions that you missed.

The times listed below are ONLY for the 3088 & 3090 SLB students with halfway start times:

Usual lab time Lab practical starts at7:30am 8:55am9:00am 10:25am11:00am 12:25pm1:10pm 2:35pm2:30pm 3:55pm5:10pm 6:35pm6:10pm 7:35pm

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Eisen Office Hours

Friday 3:00 - 5:00

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Other Things

• Study Guides will be posted over the next few days

• Final is 2/3 about animals, 1/3 about rest of course

• Review sessions to be scheduled

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Vertebrate Origins

!8Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016

Ciliated larvae

Am

bulacrariansC

hordates

Common ancestor (bilaterally symmetrical, pharyngeal slits present)

Echinoderms

Hemichordates

Lancelets

Tunicates

Vertebrates

Radial symmetry as adults, calcified internal plates, loss of pharyngeal slits

Vertebral column, anterior skull, large brain, ventral heart

Notochord, dorsal hollow nerve cord, post-anal tail

Focus on Vertebrates

Phylogeny of the Living Vertebrates


Amniotes

Lampreys

Hagfishes

Lungfishes

Amphibians

Chondrichthyans

Ray-finned fishes

Coelacanths

Focus on Two Key Things


Amniotes

Lampreys

Hagfishes

Lungfishes

Amphibians

Chondrichthyans

Ray-finned fishes

Coelacanths

Getting to Humans

In-Text Art, Ch. 33, p. 693 (1)

In-Text Art, Ch. 33, p. 707


Amniote ancestor

Crocodilians

REPTILES

Tuataras

Squamates

Turtles

Theropods, including birds

Mammals

MAMMALS

In-Text Art, Ch. 33, p. 696


Reptiles

Eutherians

Marsupials

Prototherians

Figure 33.28 Major Groups of Eutherians Diversified as the Continents Drifted Apart


Million years ago

Africa

Africa

Africa

Africa

Africa

South America

SE Asia

SE Asia

Proto-Europe

Proto-Europe

Proto-Europe

Laurasia

Laurasia

Laurasia

Laurasia

Laurasia

Laurasia

Madagascar, Africa

Africa

Africa

Africa, Asia

Africa, Middle East

North, South America

SE Asia

SE Asia

Tropics of Africa, Americas, AsiaNorth America, EurasiaWorldwideWorldwide except AustralasiaWorldwide except Australasia

Africa, southern Asia

Worldwide except AustralasiaWorldwide except AustralasiaWorldwide

Current native distribution

Earliest FossilsGroup

African insectivoresLong-nosed insectivores

Aardvarks

Elephants

Hyraxes

Armadillos

Colugos (“flying lemurs”)Tree shrews

Primates

Rabbits and pikasRodents

Shrews, moles, and relatives

Bats

PangolinsOdd-toed hoofed mammalsEven-toed hoofed mammals

Figure 33.30 Phylogeny of the Primates


Pleistocene

Gibbons

Orangutans

African apes and humans

Miocene

Oligocene

Eocene

PaleocenePliocene

LemursProsimians

Mid-to-late Cretaceous

Anthropoids

Lorises

Tarsiers

New World monkeys

Old World monkeys

Figure 33.34 A Phylogenetic Tree of Hominins


Ardipithecine ancestors

Paranthropus boisei

Homo sapiens (now worldwide)

Million years ago

Australopithecus afarensis (Lucy)

Australopithecus africanus

Paranthropus aethiopicus Paranthropus robustus

Homo floresiensis (extinct 17,000 years ago)

Homo erectus (extinct 250,000 years ago)

Homo ergaster

Homo neanderthalensis (extinct 28,000 years ago)

Homo habilis

Africa only Expansion out of Africa

Vertebrate Evolution


How Do People Figure This All Out?

Get Samples of Diverse Organisms


Gather Lots of Data


Including Fossils


Infer a Phylogenetic Tree


Phylogeny of the Living Vertebrates


Amniotes

Lampreys

Hagfishes

Lungfishes

Amphibians

Chondrichthyans

Ray-finned fishes

Coelacanths

Major Innovations in Vertebrate Evolution


Bony skeleton, swim bladder/lung

Jawless fishes

Lobe-limbed vertebrates

Amniotes

Gnatho- stomes (”jaw mouths”)

Terrestrial limbs and digits

Lobe fins

Lampreys

Internal nares

Vertebrae

Jaws, teeth, paired fins

Hagfishes

Amniote egg

Lungfishes

Amphibians

Chondrichthyans

Ray-finned fishes

Coelacanths

How Did People Figure This All Out?

Comparative Biology


Post anal tail

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Vertebrae

No

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Jaws

No

No

Yes

Yes

Yes

Yes

Yes

Yes

Lobe Fins/Limbs

No

No

No

No

Yes

Yes

Yes

Yes

Terrestrial Limbs

No

No

No

No

No

No

Yes

Yes

Other

Amniotes

Lampreys

Hagfishes

Lungfishes

Amphibians

Chondrichthyans

Ray-finned fishes

Coelacanths

Overlay Onto Tree


Post anal tail

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Vertebrae

No

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Jaws

No

No

Yes

Yes

Yes

Yes

Yes

Yes

Lobe Fins/Limbs

No

No

No

No

Yes

Yes

Yes

Yes

Terrestrial Limbs

No

No

No

No

No

No

Yes

Yes

Amniotes

Lampreys

Hagfishes

Lungfishes

Amphibians

Chondrichthyans

Ray-finned fishes

Coelacanths

Infer Likely Ancestral and Derived Traitss


Post anal tail

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Vertebrae

No

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Jaws

No

No

Yes

Yes

Yes

Yes

Yes

Yes

Lobe Fins/Limbs

No

No

No

No

Yes

Yes

Yes

Yes

Terrestrial Limbs

No

No

No

No

No

No

Yes

Yes

Amniotes

Lampreys

Hagfishes

Lungfishes

Amphibians

Chondrichthyans

Ray-finned fishes

Coelacanths

Major Innovations in Vertebrate Evolution


Bony skeleton, swim bladder/lung

Jawless fishes

Lobe-limbed vertebrates

Amniotes

Gnatho- stomes (”jaw mouths”)

Terrestrial limbs and digits

Lobe fins

Lampreys

Internal nares

Vertebrae

Jaws, teeth, paired fins

Hagfishes

Amniote egg

Lungfishes

Amphibians

Chondrichthyans

Ray-finned fishes

Coelacanths

The Vertebrate Body Plan (not in all …)


Anterior skull enclosing a large brain

A jointed, dorsal vertebral column replaces the notochord during early development.

Internal Organs suspended in a coelom

Well-developed circulatory system driven by a ventral heart

Rigid Internal Skeleton


Vertebrate Evolution

• The structural features can support large, active animals.

• Internal skeleton supports an extensive muscular system that gets oxygen from the circulatory system and is controlled by the nervous system.

• These features allowed vertebrates to diversify widely.

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Photo 33.105 Family Balaenopteridae: fin whale (Balaenoptera physalus); Baja California, Mexico.



Sister group for all other vertebrates

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Hagfish

Photo 33.18 Pacific hagfish (Eptatretus stouti).

You’ve Been Slimed


Anterior skull enclosing a large brain

A jointed, dorsal vertebral column replaces the notochord during early development.

Internal Organs suspended in a coelom

Rigid Internal Skeleton

Well-developed circulatory system driven by a ventral heart

The Vertebrate Body Plan

Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2016 35

Lampreys


Lampreys

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• Complete cranium and cartilaginous vertebrae. • Complete metamorphosis from filter-feeding larvae (ammocoetes), which are similar to lancelets. • No bone, no jaws, but cartilaginous vertebrae are present • Sucker- like mouth with rasping teeth • Many species are ectoparasites of fish

Photo 33.17 Anadromous lamprey (Petromyzon marinus); Rhode Island.


Vertebrae Evolution

Lampreys have cartilaginous vertebrae so infer that vertebrae evolved here.


Gnathostomes - Jaw Mouths

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• Jaws evolved from gill arches late in the Ordovician. • Name from Greek gnathos (jaw) & stoma (mouth)

Figure 33.12 Jaws and Teeth Increased Feeding Efficiency



33.3 What New Features Evolved in the Chordates?

• Jaws improved feeding efficiency and prey capture.

• Jawed fishes diversified rapidly and became dominant.

• Teeth made feeding even more efficient. Chewing aids chemical digestion and improves extraction of nutrients from food.

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Sling Jawed Wrasse

• Previous lecture: ! Bis2B !


Chondrichthyans (sharks, rays, skates, chimaeras):


• Skeletons of cartilage • Flexible, leathery skin • Sharks swim using lateral undulations of the body. • Skates and rays swim by flapping enlarged pectoral fins.

Chondrichthyans


Megalodon


• One of the largest vertebrate predators, 50-60ft • Largest known tooth ~8 inches • Extinct about 1.5 million years ago • Likely fed on whales and other large prey

Great White Shark


• Up to 20ft and 5,000 lbs; apex predator • Feeds on marine mammals, fish, and seabirds • Likely a close relative of Megalodon • Global distribution; migratory behavior (12,000 miles/ 9 months)

Farallon Islands

Bones


• One lineage of gnathostomes gave rise to the bony vertebrates with internal skeletons of calcified, rigid bone.

• Some early bony fishes had gas-filled sacs that supplemented the gills in gas exchange.

Ray Finned Fishes


• In ray-finned fishes, the sacs developed into swim bladders, organs of buoyancy.

• Allows fish to maintain position at specific depths.


Ray Finned Fish- Actinopterygii

• Largest group of bony fish; 30,000 described species • Both freshwater and marine, diverse feeding habits



Big Change Coming - Invasion of Land

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• What features contributed to the invasion of and diversification on land?


Where Else Have We Discussed Invasion of Land

Which of the following is NOT considered to be a critical adaptation for the invasion of the land by eukaryotes?

A. Pigments

B. Mutualistic associations with fungi C. Hardened cuticle

D. Waxy cuticle

E. Jaws 52


Where Else Have We Discussed Invasion of Land

Which of the following is NOT considered to be a critical adaptation for the invasion of the land by eukaryotes?

A. Pigments

B. Mutualistic associations with fungi C. Hardened cuticle

D. Waxy cuticle

E. Jaws 53

Land Plants …


Plantae

Retention of egg in the parental organism; plasmodesmata; similarities in mitosis and cytokinesis

Chloroplasts primary endo-symbiosis)

Chlorophyll b; starch storage

Protected embryo; cuticle; multicellular sporophyte; gametangia; thick-walled spores

Branched apical growth

Land plants (embryophytes)

Stoneworts (“green algae”)

Coleochaetophytes (“green algae”)

Other “green algae”

Chlorophytes (most “green algae”)

Red algae

Glaucophytes

Green plants

Streptophytes


Arthropods

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Arthropod Key Feature: Exoskeleton

• Exoskeleton is a thickened cuticle

• Restricts movement and gas exchange

• Requires ecdysis • Muscles attached to inside • Provides support for walking

on land, prevents drying, and provides some protection from predators.

• Aquatic arthropods were thus excellent candidates to invade land.

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Big Change Coming - Invasion of Land

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• What features contributed to the invasion of and diversification on land?

Lungs / Swim Bladder


• Lung-like sacs likely evolved much before vertebrates invaded the land • Supplemented gills when in shallow water / water low in O2

• Evolved into swim bladders in many ray-finned fish

Lobe Fins


• Bony fish that lack bony spines (rays) as part of their fins • The more muscular fins are joined to the body by a single large bone • Changes in the structure of fins allowed some fish to support

themselves in shallow water and later move onto land.

Coelacanths


Coelocanths

• Thought to have become extinct 65 mya, but living ones were found off South Africa in 1938.

• They have a cartilaginous skeleton that is a derived feature.

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More Fully Developed Lungs


• Elaboration on the lung like sacs into lungs

More Fully Developed Lungs



Tetrapods


• Limbs capable of movement on land evolved from the short, muscular fins of aquatic ancestors.

• The four resulting limbs give the tetrapods their name.

Fossils Also Important


http://www.hhmi.org/biointeractive/great-transitions-interactive

Tetrapod Limbs Are Modified Fins


Amphibians


Amphibians


~7,000 species Confined to moist habitats: lose water easily

through the skin, and eggs dry out if exposed to air.

Amniotes


Amniotes have several features that contribute to their success on dry land.

Science

BIS2C: Lecture 33: Vertebrates