Bio 2 Vertebrates

Vertebrates

Chordates with a backbone

Chordate characteristics

Vertebral column, cranium, endoskeleton of cartilage or bone, body plaN: head, trunk, tail. Full coelom, paired kidneys

Endothermic

Birds and mammals

Ectotherms

Reptiles, fish, amphibians, invertebrates

Cyclostomata

Jawless fish, naked skin, marine and freshwater, notochord and rudimentary vertebrate column

They are parasites on fish, suck body fluids

Tetrapods

Includes:

• amphibians

• Reptiles

• Birds

• Mammals

Gnathostomes

Jawed vertebrates, hinged jaws developed from gill arches

Chondrichthyes - cartilaginous fishes

Sharks, rays, skates

Have: powerful jaws and teeth, placoid scales, denser than water, 5-7 gill slits

Shark features

rows of replaceable teeth (first two rows are active), no roots, placoid scales

Shark sensory systems

• ampullary organs of Lorenzini

• Lateral line system

Ampullary organs of Lorenzini

Bioelectric organs, detect electric fields to navigate

Lateral line system

Detects vibration and current, helps with navigation and prey

Shark smell

2/3 of brain dedicated to smell

Sharks Swim Bladder?

No! They are heavier than water and instead have LARGE LIVER filled with SQUALENE to aid in buoyancy

Shark reprod

Separate sexes, internal fertilization, clasper in males

Oviparous

Lays eggs

Ovoviparous

Eggs incubate and hatch in uterus

Viviparous

Bear live young, placenta

Teeth

Are derivates of placoid scales (which are made of dentin and enamel)

Rays and skates

Are derivates of placoid scales (which are made of dentin and enamel)

Heterocercal tail

Caudal fin of cartilaginous fishes with two asymmetrical lobes

Shark fin soup

Served since Ming dynasty, Asian delicacy. Shark population have declined as much as 90% or more over the last 50 years

Osteichthyans

Bony fish

Most numerous of all fish, scale covered skin, operculum covers gills, swim bladder, external fert.

Includes:

• ray finned

• Lobe finned

Actinopterygii

Ray finned fish

Fins supported by thin, bony, flexible rays

Rayfin fish anatomy

Sickle shaped tails are faster

Rayfin scales

Ganoid - primitive bony fish

Placoid - cartilagenous fish

Cycloid, ctenoid - modern teloists

Pneumatic duct

Connects swim bladder to esophagus - gulp air

Gills

Respiration, many folds (lamellae), covered and protected by operculum, countercurrent flow

Hypotonic

Freshwater fish get in hypotonic situations

To solve: does not drink, gains water through osmosis and produce large amounts of dilute urine

Hypertonic

Saltwater fish

To solve: produce very concentrated urine

Scarcopterygii

Lobe-finned fish

Scarcopterygii features

Just a few living ex: lungfish (closest living thing to tetrapods! Mermaid?)

• pectoral and pelvic fin evolved into legs of amphibians and the first land tetrapods

tetrapods

Four legs, include amphibians and amniotes

Amniotes

Terrestrial adapted egg protection (amniotic egg!) includes reptiles, birds, mammals

Tetrapods features

• expanded brain

• Habitat diversity

• Internal fertilization

• Better vision, hearing, balance

• Stringer respiratory and circulatory system

Amphibians

Have gills or lungs depending on time because they experience metamorphosis (tadpole - adult)

Salamanders are currently threatened by a chytrid fungus

Amphibian model organism

Axolotyl

Amniotes eggs

Shelled eggs, either soft or hard are permeable to O2 and CO2

Mammal (amniote) modified egg

modified egg structure so that embryo can embed in uterine wall

Layers of non mammal eggs

Allantois, Albumin, Yolk Sac, Chorion, Amnion

Allantois

Contains waste, gets larger with age

Albumin

Stores nutrients

Yolk Sac

Reserve of nutrients, gets smaller with age

Chorion

Gas exchange

Amnion

Protects embryo in fluid filled sac

Amniotes 3 different skulls

1, 2 or 3 openings

1 opening

Mammals

2 openings

Birds

3 openings

Reptiles (except turtles)

Reptilian features

Copulatory organ (device used to transfer or receive sperm), internal fertilization

Reptilian breathing

Thoracic breathing (negative pressure, like humans, muscles expand ribcage)

Reptile skin

Tough, dry, scaly skin

• no glands

• Impermeable to water

• Periodically shed

• Dermis with chromatophores

Kinetic skull

Really strong jaws, mouth muscles and teeth

Testudines

Having a shell - turtles, tortoises

• ancient group

• Dorsal carapace

• Sharp beaks, no teeth

Squamata

Lizards and snakes

• Jacobson’s organ (smell organ)

• Venom glands

• Rattle warns off potential aggressors or distracts prey

• Snake legs are vestigial structures

Snakes movement

Vestigial girdles (vestigial so not needed any more)

Lizards

Have limbs

Nest temp

Higher temperatures means the babies will be male and vice versa

Crocodilia

Crocs, alligators

Crocodilia heart

4 chambered

Crocodilia mouth

Have a second palate which separates nose from tongue

Crocodilia teeth

Teeth in sockets (the only non-mammals that have this)

Aves - birds features

Feathers - modified scales

Air sacs - efficient breathing

Lightweight hollow thin honeycombed skeletons

reduction of organs

Single ovary, no urinary bladder

Birds evolution

Theropod dinosaur → Archaeopteryx → modern bird order → splits in two Ratite and Carinate

ratite

Flightless, flat sternum, weak pectorals ~ 40 spp.

Carinate

Flighted, keeled sternum, strong pectorals, ~ 4,400 spp.

Feathers

Molt about once a year, modified scales, 2 types: contour feathers (stiff, airfoil shape for flying) and down feathers (soft, maintain heat)

Wings

Different kinds! (Do we need to know the kinds?)

Bird brains

Complex and senses

Bird breathing

9 air sacs, full ventilation: two breathing cycles

Sensitive to airborne toxins

Beaks

Seed cracker, meat teaser, mud sifter, nut cracker, and more!

Precocial Young

Covered with down, active young, run and swim when dry, ex: ducks, geese

Altricial Young

Naked and helpless, in nest for over a week, require care from parents

Mammals

Milk producing amniotes (mammillary gland)

Most biologically differentiated group

Second palate as well!

Endothermic and HAIRY

Diphyodont

Teeth appear twice in a lifetime

Heterodont

Different teeth shapes

Mammal evolution

Synapsid reptile ancestor → cynodont → early mammals (only mouse size!) → now

Mammal features

Hair

Norms

Integumentary glands

Skulls and feeding

Hair

Body covered with hair, grows in cycles, sheds twice a year

2 types of hair

Underhair

Dense, soft, insulation

Guard hair

Course, longer, protection, coloration (includes porcupines etc!!!!)

Glands (integumentary)

Sweat glands - tubular, coiled, temperature regulation

Scent glands

Sebaceous glands

Mammary glands

Groups

Prototheria, Metatheria, Eutheria

Prototheria

“First beast” - egg laying mammals

Metatheria

“Changed beast” - pouched animals (like kangaroos)

Eutheria

“True beasts” - have placenta and a long gestation

Placenta

Organ of blood exchange between maternal and fetal blood

PALM OIL IS BAD!!!!

Guys im so tired