Vertebrate Biology #1 (Tree of Life)

For Exam #1

What are the 4 unique traits of Chordates?

1)notochord

2) dorsol (hollow) chord

3)pharyngeal slits

4)postanal tail

What are the 3 main supgroups of Phylum Chordata?

1)urochordata

2)subphylum cephalochordata

3) craniata

Subphylum Cephalochordata (Characteristics/What?)

Lancelets + amphioxus

-tiny eel like

-adults present all chordate characteristics

Subphylum Urochordata (Characteristics)

-NO BACKBONE (non vertebrates)

-Sessile marine (coral like)

-attach and filter

-adults don’t resemble chordates but juveniles do

Craniata (Vertebrata)

-Cephalization (brain w/skull(cranium))

-vertebral column (except lampreys and hagfish)

»protects spine and is a spot for muscle

Paedomorphosis

Keeping youth traits (into adult)

What are the 4 Key Evolutionary Features of Vertebrates?

1) Living internal skeleton (endoskeleton)

2) link between pharynx and breathing

3) well developed nervous system (brain and sense organs)

4) paired limbs (Move better)

Major transitions (4)

1)Jaws

2)lungs

3)limbs

4)amniotic eggs

Agnatha

Jawless

Jawed

Gnathostomata

Systematcs

The scientific study of the kinds and diversity of organisms, and their evolutionary relationships

(naming,describing,classifying organisms)

taxonomy

discipline in change of proving names for groups of organisms and establishing rules by which organisms are named

Binomial Nomenclature

Every organism has a two part name (genus and species)

Linnaeaus

Hierarchical classification

system of grouping species (kingdom>phylum>class>order>family>genus>species)

Species

-Typically similar characteristics

- a group of organisms that can naturally interbreed to produce fertile offspring

Thoughts Before Darwin

-species eternal and immutable

-few convenient morphological characteristics

-observed variations were NOT normal

19th Century (what happened??)

-RADICAL SHIFT

-species not eternal (fossils discovered)

-species were not immutable (breeding)

-variation common and important

Darwin

• Evolution by natural selection

• changes in variation in traits with population over time and between populations (divergence, speciation)

What are the 4 components of natural selection?

1) more individuals are born each generation that can survive & reproduce

2) trait variation among individuals

3)some trait variation is heritable

4) Trait differences are tied to fitness (Survival of the fittest)

Is natural selection random?

NO!!!!!!!

Is genetic variance (mutations) random?

May be

Consequences of Natural Selection

species share traits due to common ancestor and imply evolutionary relationships (phylogeny)

Post Darwinism Classification

Based on holmology NOT analogy

Homologous Structure

similarity due to ancestry (ex. limbs)

Analogous structure

Similarity NOT from ancestry

Similarity from convergent evolution-environments) (ex. bird/bat wings)

Phylogenetics

study of evolutionary relationships among species

Monophyletic

Most recent common ancestor and ALL descendants

(birds)

Paraphyletic

Most recent common ancestor but NOT all descendants

(example fish, reptiles)

Polyphyletic

Does NOT contain most recent common ancestor

(example pandas)

Vicariant Speciation

Population separated by land form

»causing natural selection into reproductive isolation to new species

Founder Effect

A few individuals migrate and speciate

(founders!)

Allopatric Speciation

Due to drift and local adaptation (diff places)

Sympatric Speciation

adaptations in same place (range)

ecological segregation

species live in same area but segregate due to habitat types

genetic sympatric speciation

-polyploidy (extra chromosomes)

»common in lants and insects

Bergmann’s Rule

Endotherms tend to be larger in colder climates

Allen’s Rule

Extremites vary in body size

Gloger’s Rule

lighter/color variance due to habitat

Superclass Agnatha- Characteristic and two orders?

Jawless, mynxiformes (hagfish), petromyzontiformes (lampreys)

Mynxiformes (What? +Characteristics?)

=Hagfish=

-no eyes

-teeth on tongue

-6 tentacles around mouth

-poorly developed dorsal fins

-2 nostrils

-no paired fins

-SLIME

Petromyzontiformes

=lamprey=

-well developed eyes

-teeth and oral disc

-no paired fins

Superclass gnathostomata-Characteristic and class and clade?

-Jawed

-Clade Osteichthyes (Bone skeleton)

-Class Chondrichthyes (Cartilage skeleton)

Clade Osteichthyes (Bone skeleton): Two classes? (What are the subclasses?)+characteristics

Bony fishes, jawed

Class Sarcopterygii (Fleshyfins)

Class Actinopterygii (Ray fins)

• Subclass chondrostei (Primitive)

• Subclass Neopterygii (Modern)

Class Sarcopterygii (characteristics and order)

=Fleshy Fins, bony,jawed=

-lepidosireniformes (lungfish)

Lepidosireniformes

=lungfish=

-elongate body

-large cycloid scales

-fins long and filamentous

Class Actinopterygii (Characteristics and subclasses)

=ray fins,bony fish,jawed=

-Subclass:Chondrostei (primitive)

-Subclass:Neopterygii (modern)

Subclass Chondrostei (characteristic and orders?)

=primitive, ray fin, bony fish,jawed=

-acipenseriformes (sturgeous and paddlefish)sturgeons

Class Chondrichthyes (Characteristics and orders?)

=cartilaginous fishes, jawed

orders

• squaliformes (dogfish sharks)

• rajiformes (skates)

• chimaeriformes (chimaeras)

squaliformes

=dogfish sharks

• fusiform body

• placoid scales

• heterocercal tail

• gill slits behind head

rajiformes

=skates

• body flattened

• pectoral fin expanded for swimming

• mouth and gill slits on bentral surface

• holes (spiracles) behind eye permit inflow of water current

Chimaeriformes

=chimaeras

• tapering tail

• skin essentially naked

• poisonous dorsal fin spine

Diphycercal Tail

Heterocercal tail (Draw)

Homocercal tail (Draw)

Placoid Scales (Draw) and what fish?

Cartilaginous fishes (small can’t see scales) Sharks and rays

Ctenoid scales (Draw) and what fish?

Flatfish/Flounders (Rough)

Ganoid Scales (Draw) and what fish?

Ganoid scales are tough, bony scales found in some fish, like paddlefish and sturgeons.

Cycloid Scales (Draw) and what fish?

Cycloid scales are smooth, overlapping, and found in bony fish such as salmon,carp,minnows,suckers,shiners

Fin key (draw)

Body shape key (draw)

Devonian (Age of________)

Fishes

Carboniferous (Age of ________)

Amphibians

Gymnophiona

Order of amphibians also known as caecilians, characterized by their elongated, limbless bodies and burrowing habits.

Urodela (caudata)

Order of amphibians that includes salamanders and newts, distinguished by their lizard-like bodies and presence of tails (show bone loss)

Anura

Order of amphibians that includes frogs and toads, characterized by their jumping abilities, tailless adult forms, and typically a smooth or warty skin, metamorphic

Amphibian Characteristics

-Terrestrial and aquatic

-Legless and/or gilled larval stage

-smooth/unpermeable skin

-egg without shell

-generally oviparous

Why was there a shift to land (amphibians)?

predation, food(fitness),competitive avoidance

Environment-shallow seas, predators in ocean

Tiktaalik roseae

-Fossil found in Canada

-Transitional fossil with mixed features (fish and amphibian)

-Fins with wrists (MOST IMPORTANT)

Mesozoic (Age of _____)

Reptiles

Class Reptilia (Sauropsids)

-Testudines (turtles)

-Squamata (lizards, snakes, wormlizards)

-Rhynchocephalia (primitive lizard

-Crocodilia (crocidiles and alligators)

Reptiles are a _______ group

Paraphyletic

Don’t include birds

Reptilian Characteristics

-Amniotic Egg

-lack larval stage

-impermeable skin

-lungs

-ecotherms

-3 chambered heart

Amniotic Egg

-Breaks ties to water (aqueous environment in the egg)

-amnion surrounding the embryo (makes aqueous environment in the egg)

-allantois (N waste)

-Yolk (nutrients)

-not hard shell always

Amniote Characteristics

-amniotic egg

-Differ in number of temporal fenestrae

1. Anapsid (no opening behind eye)

2. Synapsid (1 opening behind eye)

3. Diapsid (2 openings behind eye)

Rhipidistans

Tetrapodomorph, had ideal characteristics to transition to land, shallow water predators, double breathers (had gills and open air passageways)

Basal Reptiliomorphs

• domed skull with some kinesis

• more terretrial

Cotylosaurs

• Stem amniotes

• lizard like, insect eaters

• skull slightly amphibian

• skeletal generally more reptilian

Order Testudines

• Turtles!

• anapsid

• aquatic/terrestrial

• Main groups: cryptodira and pleurodira

• carapace and plastron

• sister to crocidles and birds

**anapsid secondarily derived

Diapsids (what is it? + groups?)

2 temporal openings

2 major groups- lepidosauria (most living reptiles) & archosauria (dinosaurs,birds)

Squamate Lizard (characteristics?)

moveable eyelids

ear openings

limbs

diurnal

Serpentes

limbless

no external ear

no eyelids

snakes HAD limbs (limb loss)

most terrestrial

Diapsid Archosaurs

The dinosaurs! (and crocodilia)

Dominant during mesozoic

died due to meteor/nuclear winter

Extinct Diapsids?

Order Ichthyosauria (dolphin look-a-like but not example of convergent evolution)

Order Plesiosauria (lochness monster lol)

Extant Diapsids?

Diapsid Lepidosaurs

Order Rhynchocephalia (living/primitive fossil reptile)

Order Squamata (lizards,snakes,worm lizards)

Stem Archosaurs

Order Thecodonta

Order Crocodilia

Extant

alligators and crocidiles

long,tubular bodymlong snout with tipped nostrils

semiaquatic

Order Pterosaunia

Pterodactyls

wing membrane

unkeeled sternum (Unlike birds)

Order Ornithischia

bird hipped heribore dinos

some quadrapedal and some bipedal

many times prey for theropods

Order Saurischia

2 groups- theropods (bi) and sauropods (quad & herbivores and huge)

Limb under body posture

Bird Characterisitcs

1. Feathers

2. 4 chambered heart

3. strictly oviparous

4. one ear ossicle (ear bone)

5. endothermic homeothermic

6. flow through respiratory system

7. Bill (no teeth)

8. Hollow/fusion of bones

9. excrete uric acid

What changed so birds could fly? (Evolutionary Changes)

• weight reduction

  • bones are hollow and often fused

  • one ovary, gonads reduced in off season

  • loss of teeth

  • rapid digestion

• Size reduction (much smaller than other vertebrates before)

• Flapping flight mechanics

  • feathers

  • homeothermy

  • keeled sternum

  • furcula

Stem Paraves

• Derived group of theropods with birdlike characterics (bird dino!)

  • flexible rotating wrists

  • shift in shoulder join

  • (prey manipulation and range of motion)

  • keeled sternum+flappable arms

  • furcula

Archeopteryx

Link between dinosaurs and birds (had both traits)

Transitional fossil (helped darwin’s theory since same time ish)

IMPORTANT BIRD FOSSIL

• clawed forelimbs

• teeth

• long bony tail

• sternum unkeeled

• feathers

• furcula

What are the 4 hypotheses of Flight Evolution?

1.Arboreal (trees down)

2.Cursorial (ground up)

3.Cursorial II (trap prey)

4.Cursorial III (water up)

Acanthostega

Extinct

-More aquatic than terrestrial

-ceratobrachials (internal fish like gills)

-tail long and fish like with fin rays

-polydactyly (more than 5 digits(has 8))

**implies that 5 toed condition is derived

Ichthyostega

Extinct

1st good fossil of land vertebrate

vertebrae fishlike (no interlocking connections)

pectoral and pelvic girdles are strong

polydactyly (7 digits)

Temnospondyli

Extinct

more aquatic,flat immobile skull, had 4 fingers

Derpy flat dino

Lissamphibia

Extant

Modern amphibians

Loss of bone in skull,loss of scales,4 digits,2 middle ear bones,weak teeth, 3 chambered heart

Problems with Land Life? Fish>Amphibians

1 Gravity-affected skeleton on land

2 locomotion-propulsion use of limbs

3 breathing- oxygen more concentrated, gills collapse and desiccate

4 feeding-must use jaws,teeth and tongue

5 reproduction- eggs desiccate quickly

6 outer covering- desiccate

7 pumping blood-gravity

8 sensory systems conduct differently

Cretaceous + after K-Pg (Age of ________)

Birds