Bio of Vertebrates - Exam 1

Chapter 1: Diversity, Classification, and Evolution of Vertebrates. Chapter 2: Vertebrate Relationships and Basic Structure

How many extant species of vertebrate are there?

71,000

Hagfishes and Lampreys

Cyclostomata

Sharks, rays, and chimaeras (ratfishes)

Chondrichthyes

Bony fishes

Osteichthyes

Salamanders, Frogs, and Caecilians

Lissamphibia

Turtles

Testudines

Tuatara, lizards, and snakes

Lepidosauria

Crocodilians

Crocodylia

BIRDS!!!!

AVES!!!

Mammals

Mammalia

Vertebrates range in…

-Size (0.1 go to over 110,000 kg)
-Habitats (sea floor to mountain tops)
-Diets and feeding methods
-Reproductive behavior and modes of reproduction

Extant diversity has evolved over how many years?

500 million

Jawless vertebrates

-No jaws; sucker mouth
-No internal hard tissues/bones
-Elognate body
-Smooth, scaleless, slimy skin
-Marine, but many lampreys spawn in freshwater
-No longer grouped together in “Agnatha”… two independent lineages. 

Myxiniformes

-Hagfishes
-~75 species
-Benthic marine scavengers
-Lack vertebrae and other vertebrae features
-Sometimes included in Craniata, but not Vertebrata.

Petromyzontiformes

-Lampreys
-~40 species
-Parasites (usually of bony fishes)
-Mostly marine and anadromous
-Some smaller freshwater species

Gnathostomes

jawed… is all other vertebrates BESIDES FOR Myixiniformes and Petromyzonitofrmes

anadromous

migrate up streams to spawn in freshwater.

Chondrichthyes

-Cartilaginous fishes
-Jaws and teeth
-Skeleton entirely cartilaginous (no bone)
-Marine predators
-15 cm to 10 m in length

Elasmobranchii/Neoselachii

-Sharks, skates, and rays
-1277 species
-Under Chondrichthyes
-Mostly marine, some freshwater
-Series of gill slits
-Skin with denticles/sandpaper feel
-Skates and rays = dorsoventrally flattened

Holocephali

-Ratfishes
-~50 species
-Under Chondrichthyes
-Marine bottom-dwellers
-Little known

Osteichthyes

-Bony fishes
-Most diverse and varied group of vertebrates
-Over 34,000 extant species
-In virtually all marine and freshwater habitats
-Jaws present (teeth in some)
-Skeleton contains bone (at least some)
-Single gill opening on each side, covered by a bony operculum

Sarcopterygii

-Lobe-finned fishes
-Contains classes Dipnoi and Actinistia
-Technically, also includes all tetrapod vertebrates.

Dipnoi

-Lungfishes
-6 species
-Under Sarcopterygii
-Africa, South America, Australia
-Breath air and often move over land

Actinistia

-Coelacanths
-2 species
-Deep ocean off Africa and Indonesia
-Fishes most closely related to tetrapod vertebrates

Actinopterygii

-Ray-finned fishes
-Over 34,000
-Under Osteichthyes

Polypteriformes

-Bichirs and reedfish
-Bichirs = African reed fish; 12 species
-Freshwater rivers and swamps
-Under Osteichthyes

Acipenseriformes

-Sturgeons and paddlefishes
-Sturgeons and paddlefishes; 25 & 2 species remaining
-Overfished as sources of caviar
-Paddlefishs = only in Miss. River and Yangtze Rivers
-Under Osteichthyes

Neopterygii

-Modern bony fishes
-Gars = 7 species from earlier radiation
-Bowfin = 1 species from earlier radiation
-Under Osteichthyes

Teleostei

-Teleosts
-Over 34,000 species
-Very diverse in form, habitat, and habits
-Includes most familiar fishes
-Many specializations of body form and jaws
-Under Neopterygii

Lissamphibia

-All extant amphibians
-Aquatic larvae and terrestrial adults
-Larvae have gills, adults have lungs
-Bare, moist skin
-Skin used for respiration and water/ion exchange
-Predator as adults (some larvae herbivorous)
-Dependent on water for reproduction

Caudata

-Salamanders
-765 (750) species
-4 legs
-Elongate body and tail
-Mostly terrestrial as adults
-Most N. Am. species use protrusible tongue to capture prey.

Anura

-Frogs and toads
-7,350 species
-Short body, no tail, and large head
-Large hind legs for hopping/jumping
-Extensible, sticky tongue for prey capture

Gymnophiona

-Caecilians
-215 (205) species
-Legless, elongate body
-Burrowing or aquatic

Testudinia

-Turtles
-361 (348) species
-Body enclosed within a bony shell
-Marine, freshwater, and terrestrial species
-Dry, scaly skin
-No teeth, but keratinaceous beak

Lepidosauria

-Tuatara, lizards, and snakes
-~11,000 species
-Dry, scaly skin
-Marine, freshwater, and terrestrial species

Tuatara

-Only one species
-Small New Zealand islands

Lizards

-Over 7,000 (6,459) species
-Most have 4 legs
-External ear openings

Snakes

-Specialized lizards
-Over 4,000 species (3,619)
-No legs (some remnants)
-No external ears

Crocodilia

-Alligators and crocodiles
-26 species
-Up to 7 m long
-Semiaquatic predators
-Skin armored with osteoderms (bony plates) beneath scales
-Extensive parental care for eggs and young
-Belong to the same lineage (Archosauria) as dinosaurs and birds.

Aves

-BIRDS!!!
-10,912 (10,806) species
-Lineage of dinosaurs that evolved flight
-Feathers on skin
-Forelimbs modified as wings
-No teeth in extant forms, but a keratinaceous bill
-Some are secondarily flightless
-Belong to Archosauria along with dinosaurs and crocodylians- “feathered, flying, reptiles”

Mammalia

-Mammals
-~5,780 (5,416) species
-Hair on skin
-Mammary glands: secrete milk to nourish young

Prototheria

-Monotremata (Egg-laying mammals)
-Only 4 species; Platypus and Echidnas
-Occur in Australia and New Guinea
-Oviparous: lay eggs
-Young nurse after hatching

Theria

-Eutheria (placental) mammals
-Over 5,416 species
-Most extant species
-Viviparous with a long gestation period, large young

Metatheria

-Marsupialia (pouched mammals)
-~361 species
-Dominant mammals in Australia
-Only the Opossum in N. America
-Viviparous with a short gestation period
-Young born very small
-Development of young completed in external pouch

Systematics

-Biological Classification
-Naming and categorization of organisms into groups
-Biological classification is hierarchical, with groups nested within groups
-Individuals within a species
-Species within a genus
-Genera within a family
-Families within an order, etc.
-Hierarchical classifications can reflect evolutionary history
-Each branching event represents the evolutionary divergence of two lineages, from a common ancestor.

Traditional Systematics

-Classification reflects similarity of organisms
-Groups are artifical and arbitarily defined; are not necessarily monophyletic
-Groupings are based on all characteristics shared by organisms
-Resulting dendrograms do not reveal character evolution
-Classification levels are ranked

Phylogenetic Systematics/Cladistics

-Classification reflects evolutionary history
-Groups are natural, reflect evolutionary relationships- are monophyletic groups
-Groupings are based only on shared derived characteristics
-Resulting cladograms reveal patterns of character evolution
-Classification levels have no rank. 

Tenets

-Only shared similarities that are derived are useful in deducing phylogenetic relationships
-Speciation produces two sister species
-Speciation is recognizable only if the divergence of two populations is accompanied by the origin of a derived character state.

Phylogeny

The evolutionary history of a lineage

Character

Trait or feature of an organism

Character State

Nature or condition of a character in a particular organism

Plesiomorphic

Ancestral character state

Apormorphic

Derived character state

Synapomorphic

Derived character state that is shared by two or more groups

Parsimony

The most likely evolutionary path is that which requires the least steps (character transition)

Sister Groups

Two groups that are more closely related to one another than to any other group.

Monophyletic

A group containing an ancestor and all of its descendents.

**Many historically recognized groups, including the Reptilia, are not this.

Clade

a monophyletic group

Paraphyletic

Group that includes members of several clades, but not their common ancestor. 

Polyphyletic

Group that includes members of several clades, but not their common ancestor.

Metazoa

-Multicellular animals
-Blastula (early embryo) forms hollow ball
-Sex cells (gametes) formed in special organs (gonads)
-Motile sperm with long tails
-Gastrulation produces multiple (2 or 3) germ layers in the embryo, a derived feature of those higher than sponges. 

Bilataria

-Three germ layers: Ectoderm, Mesoderm, and Endoderm
-Discrete, complex organs
-Bilateral symmetry- at least as larvae
-Motile adults

Coelomata

-Coelomates
-Coelom (body cavity) forms within mesoderm
-Contains two sister clades: Protostomata and Deuterostomata

Protostomata (-ia)

-Protostomes
-Blastopore (first opening in embryo) becomes the mouth

Deuterostomata (-ia)

-Deuterostomes
-Blastopore becomes the anus
-Contains 3 phyla: Echinodermata (sea stars and sea urchins), Hemichordata (acorn worms and pterobranchs), and chordata (chordates)

Phylum Chordata

-Chordates
-Subphylum Urochordata (tunicates - sea squirts)
-Subphylum Cephalochordata (lancelets - Amphioxus)
-Subphylum Vertebrata

Shared derived features (synapomorphies) of chordates

-Notochord (at least in early life stages)
-Dorsal hollow nerve cord
-Perforated pharynx with an endostyle (ciliated, glandular groove)
-Post-anal tail (present at least in larvae)

Urochordata

-Tunicates
-Marine
-Filter-feeders- perforated pharynx filters small food particles from water
-Most are sedentary (attach to substrate) as adults
-Free-swimming larvae better exhibit chordate features
-Possible sister group to Vertebrata??

Cephalochordata

-Lancelets (amphioxus)
-Marine
-Small (<5 cm)
-Filter feeders
-Free-swimming larvae
-Most are burrowing, sedentary as adults
-Fish-like locomotion
-Myomeres (body muscle segments) along both sides of body, as in Vertebrata

Characteristics unique to Vertebrata

1.) Cranium (skeletal structure that supports and protects the brain and multicellular sense organs)
2.) Tripartite brain (in 3 parts)
3.) Multicellular sense organs (optic/eye/vision, olfactory/nose/smell, otic/inner ear/balance and hearing)
4.) Vertebrae (absent in Myxiniformes, only rudimentary in Petromyzonitiformes… thus preferring Craniata over Vertebrata)
5.) Accessory digestive glands (+ liver, gall bladder, pancreas, and spleen)
6.) Multi-chambered ventral heart
7.) Muscularized pharynx and gut
8.) Embryonic Neural Crests (contribute to the formation of many structures (ex: sensory) in vertebrates.)

How many body structures do vertebrates have?

10

Vertebrate Body Structure List

1.) Integument (External covering)
2.) Skeletomuscular system (skeleton and muscles)
3.) Digestive System (mouth, pharynx, and gut)
4.) Respiratory System (skin, gills, and lungs)
5.) Cardiovascular System (heart, blood)
6.) Excretory System (kidneys)
7.) Reproductive System (gonads)
8.) Nervous System (Central and peripheral nervous systems)
9.) Endocrine System
10.) Sense Organs (sight, smell, taste, hearing, touch)

1.) Integument (External covering)

Skin and its derivatives (ex: glands, scales, dermal armor, feather, claws, pigment cells)
Functions for protection, exchange, and sensation

2.) Skeletomuscular system (skeleton and muscles)

Functions for structural support and movement of body. Skeleton (bone, cartilage and ligament) provides passive structural support and directs actions of muscles. Muscle contracts (or creates tension). Tendons connect muscle to bone.

3.) Digestive System (mouth, pharynx, and gut)

Functions for intake, breakdown, and absorption of food.
Vertebrates have a muscularized gut

4.) Respiratory System (skin, gills, and lungs)

Functions for uptake of oxygen and release of CO2.
Cutaneous Respiration - O2 and CO2 diffuse across skin.
Gills - gas exchange in water
Lungs - gas exchange in air

5.) Cardiovascular System (heart, blood)

Functions to transport materials to all tissues of body
Heart - muscular pump has 3 (or 4) chambers
Blood - liquid plasma plus various blood cells
Vessels - arteries, veins, capillaries

6.) Excretory System (kidneys)

Functions: waste excretion, water and ion balance
Also done by gills and skin in aquatic taxa

7.) Reproductive System (gonads)

Functions to produce gametes and sex hormones
Ovary: female gonad, produces ova and estrogen
Testis: male gonad, produces sperm and testosterone

8.) Nervous System (Central and peripheral nervous systems)

Functions to integrate sensory information and coordinate muscle and organ activity
Central Nervous System: brain and spinal cord
Peripheral Nervous System: nerves to body

9.) Endocrine System

Also involved in control/coordination
Secretes messenger chemicals (hormones) into blood stream

10.) Sense Organs (sight, smell, taste, hearing, touch)

Also: lateral line, electroreception, balance, temperature
Functions to provide information about the environment to the central nervous system.

What’s the skeletomuscular system of vertebrates?

-Notochord

-Cranial Skeleton and Musculature

-Axial Skeleton and Musculature

-Appendicular skeleton and musculature

Notochord

Stiff, fluid-filled longitudinal supportive rod.

Has outer fibrous sheath to which muscles attach

Stiffens body lengthwise, directs muscle action for undulatory locomotion.

Replaced (partly to wholly) by vertebrate in more derived vertebrates

Cranial skeleton and musculature

Skull

Cranium plus pharyngeal arches (and derivatives)

Houses and protects brain and sense organs.

Food intake, sensory input, and respiration (gills)

Axial Skeleton and musculature

Vertebrate, ribs, and trunk musculature

Primary means of locomotion in fishes

Primarily for supporting body weight in tetrapods.

Appendicular skeleton and musculature

Paired fins and limbs

Pectoral and pelvic girdles and appendages

Fins are primarily for steering/orienting

Limbs are primary means of locomotion in tetrapods