Exam 4 Zoology Prep

Creator, help us all

What are the 5 main classes of Echinodermata?

Holothuroidea (sea pickle), Asteroidea (sea stars), Echinoidea (sea urchin), Ophiuroidea (brittle stars/snake-like), Crinoidea (sea lilies/feathered stars)

What are the characteristics of Asteroidea?

Sea stars

Multiple arms radiating from a central disc

Shorter Arms

a water vascular system used for movement and feeding

Active predator with gut that comes out

What are the characteristics of Ophiuroidea?

Brittle star

Long, slender, flexible arms that are sharply marked off from central disk (No rounded edges, just shoots from central disc/center)

Ambulacral grooves closed off by ossicle plates (No divot/dent like a sea star, but instead flat)

What are the characteristics of Echinoidea?

Sea Urchins

Test (interlocking armor under spikes/spines)

Aristotle’s Lantern (Teeth-like structure used for eating)

Eat anything with hard crust

Live on sea floor

What the characteristics of Holothuridea

Sea pickles

Live on sea floor/bottom feeders

No cephalization (No concentration of nerves to head/no head)

Anus opens into large cloaca (chamber), to bring in water to bring in oxygen and remove nitrogenous waste

Ossicles reduced to small plates/spicules (They’re smooth)

Water vascular system is closed (they have their own blood/coelomic fluid)

What are the characteristics of Crinoidea

Sea lilies

Most ancient of all classes

Suspension feeders (They’re sessile and catch prey with their pinnules/ feathery arm thing)

Believed that they lost their stock throughout evolution due to ocean acidification & climate change which caused calcium to be hard to come by

What are the characteristics of the Phylum Hemichordata

Acorn worms & colonial animals

Pharyngeal gill slits/pouches (Holes/slits in the neck to push water through and out), also exchange oxygen, not all organisms will use it

Dorsal hallow nerve chord

What are the two main classes of Hemichordata ?

Class Enteropneusta (Acorn worms)

Class Pterobrancia (small colonial animals)

What are the main traits of Chordata?

Pharyngeal slits/pouches

Dorsal Hallow nerve chord

Notochord

Post-anal tai

Endostyle

What is a Pharyngeal Slit?

Initially used for filter feeding

turns into jaws

Can turn into gills

Can turn into part of ear

Dorsal Hallow Nerve Chord

Turns into nerve chord

Connects/turns into part of your brain

Notochord

Sits below dorsal hallow nerve cord

Develops by wrapping itself around the DNC to then become the vertebrae (spine)

Provides support (will turn into bones/cartilage)

Postanal Tail

used for locomotion

Vestigial in humans (Develops into tailbone which is later lost in humans)

Endostyle

On ventral wall of pharynx, produces mucus to gather food particles

In humans, turns into thyroid gland which regulates metabolism

#1

Pharyngeal Slit/Pouch (picture)

#2

Endostyle (picture)

#3

Dorsal Hallow Nerve Chord (picture)

#4

Notochord (picture)

#5

Post Anal Tail (picture)

What are the three main subphyla of the Phylum Chordata?

Cephalochordata (lancelet/fish-like most common ancestor)

Urochordata (Seasquirt)

Vertebrata (Human)

What is the main characteristic of the subphylum Urochordata?

Sessile/Stick to something usually as an adult (not all)

Move around in larval stage

Surrounded by nonliving cellulose test called a Tunic

Only when it’s in larval form, it’ll have all chordate (lanclet) features, then as adult, stick to something

What is the main class of Subphylum Urochordata?

Class Ascidiacea (sea squirts)

What are the characteristics of the class Ascidiacea?

Solitary & colonial species

Sessile as adults

during metamorphosis, notochord and tail disappear & dorsal nerve cord is greatly reduced.

What tunicate/Chordate is used for medicine and what medicine?

Ecteinascidia turbinata/Mangrove tunicate

Trabectedin (anti-tumor drug)

What are the main characteristics of Subphylum Cephalochordates?

Lancelets

Has five shared Chordata characteristics

is a model species that represents an old ancestor (not common ancestor, just similar)

What are the main characteristics of Subphylum Vertebrata?

Known as clade Craniata (has skull-like thing)

How are the early vertebrate characteristics different form other subphyla in chordata?

Large size & active lifestyle

(Notochord Turns into endo skeleton) allows greater speed and mobility

Well developed cranium

Tripartite brain (three regions)

Various sensory organs

What are protochordates?

Hemichordata, Urochordata, cepholochordata

What are the different parts of the brain in an early vertebrate character?

Forebrain

Midbrain

Hindbrain

Brain Stem

What does the Forebrain do?

Coordinates movement & sensory info (smell)

Emotions, problem solving

learning

(Cerebrum)

What does the Midbrain do?

Visual & auditory processing

Movement of eye

motor movement

(Optic lobe)

What does the Hindbrain do?

Autonomic functions; relay info

coordinate voluntary muscle movement

balance and equilibrium

(Cerebellum)

What does the Brain Stem do?

Regulate involuntary actions (sneezing, vomiting, heart rate swallowing & breathing)

Sleep cycle

Conduct messages between brain and spinal cord

(Medulla oblongata)

What are some characteristics of early Vertebrae?

Endoskeleton (cartilage → bone)

Bone’s original function was mineral storage

What resulted of increased metabolic demand?

(Increased need for food/energy production/way to get oxygen)

Muscular pharynx (muscle in throat to help push food down)

Vascularized gills (allows for increased ability to take oxygen from water and then use it in the blood)

Multi-chambered heart

What are Ostraderms?

A clade → Armored Extinct Jawless fish

Agnatha meaning?

Jawless

What are the two main classes of Agnathans?

Myxini (Hagfishes)

Pteromyzontida (lamprays)

What are the characteristics of Agnathans?

Lack: Jaws, internal ossification (development of bone from other connective tissue), scales and paired fins

Have: Pore-like gill openings & eel-like bodies

Characteristics of Class Myxini?

(Hagfish)

All marine

Predators & scavengers (bore into carcasses)

Nearly blind but have acute sense of smell

Characteristics Class Pteromyzontida?

(lampreys)

Parasitic species that attach to fish with sucker-like oral disk & sharp teeth rasp through flesh

Non-parasitic species don’t feed as adults, digestive track degenerates, spawn and die

What is the Sea Lamprey Invasion of the Great Lakes Region?

Initially, no lampreys were ever in the U.S Great lakes,

then in 1913-1918, the Welland Ship Canal was deepened allowing sea lampreys to invade lakes

Destroyed lake trout fisheries & depleted stock of most other fishes by 1951

What is Gnathostomata?

A clade ^→ HAS Jaws

Characteristics of Gnathostomata?

Has an ostracoderm ancestor (originally jawless ancestor)

Jaws are modified gill arches (A gill moved down to become jaw)

What is a placoderm?

Extinct class or armored jawless fishes

Characteristics of Class Chondrichthyes?

(Sharks, sawfish, Rays, Skates, and Chimaeras) (Cartilaginous Fishes)

Mostly Marine

Has cartilage → No bones

Descended from a bony ancestor

Well-developed sense organs

Powerful Jaws

Well-developed sense organs

Powerful Jaws

Heavier than water → most must move or sink

Body hydrodynamic (well adapted to moving in water, doesn’t require a lot of energy)

What are the two main Subclasses of Class Chondrichthyes?

Elasmobranchii (sharks & rays)

Holocephali (chimaeras)

What are characteristics of Subclass Elasmobrancii?

5-7 pairs of gill slits

Tough leathery skin with tooth-like placoid scales

Asymmetrical heterocercal tail → provides thrust and lift

Can sense low frequency vibrations with lateral line system (neuromasts) → (mechanoreceptors)

What are characteristics of (Rays) Subclass Elasmobranchii?

Dorsoventrally flattened bodies with enlarged pectoral fins

Teeth adapted to crush prey

Modified dorsal respiratory spiracle & ventral gill slits

What is the main Superclass of the Phylum Chordata?

Osteichthyes (Bony Fishes)

What are characteristics of Superclass Osteichthyes?

Paraphyletic (tetrapods share ancestor with lobe-finned fishes)

Bone replaces cartilage during development

Swim bladder for neutral buoyancy → derived from gut

The bony operculum over gills increases respiratory efficiency

What are the two main classes of Superclass Osteichthyes?

Actinopterygii (Most common) (ray-finned fish/fins look like delicate fans)

Sarcopterygii (Rarer) (lobe-finned fish)

What are characteristics of Class Actinoptergii?

Ancestral forms from Devonian period

Heavily armored with ganoid scales (don’t overlap)

Modern teleost fish comprise almost half of all vertebrates

Dermal armor replaced by light, thin, flexible cycloid (smooth & round) and ctenoid (has tiny teeth-like edges) scales

Jaw is modified to protrude & suction food

What are the characteristics of Class Sarcopterygii?

(Lobe-finned fish)

8 extinct species

Pectoral & pelvic fins supported by stout bones & strong muscles

Has gills AND lungs

Have Ambulatory fins (“walking fins”/ can use them for locomotion along bottom of ocean)

The Coelacanths (believed to be extinct) was re-discovered in 1938 off the coast of Africa and is unchanged

In early evolution of terrestrial vertebrates, what happened?

Aquatic features were repurposed in early verts to explore terrestrial habitats

→ Air filled cavities connected to pharynx once worked as a swim bladder

Bony fins originally were then modified for support & underwater locomotion

What were some adaptions to living on land?

(important event in metazoan evolution)

Access to unoccupied niches & resources → vascular plants, pulm snails and tracheate arthropods were already well established on land

Lower predation pressure

More opportunities for adaptation

What were the new physiological requirements of the adaptions to living on land?

Oxygen 20x richer than air in water (Increase vascularization & double circulation)

Air is 1000x less dense than water (skeleton and muscles develope to support more weight)

Temp fluctuate more rapidly in air (behavioral strategies evolve)

What are some characteristics of the early terrestrial vertebrates?

Transition bwtn lobe-fin fishes and tetrapods

Had lungs and well muscular limbs & skeletal support system

What taxonomy is Amphibia?

Class

What is the Amphibia Crisis?

1/3 of all species threatened

Chytridiomycosis (disease that affect’s skin → death) responsible for killing frogs)

Climate change affects it too

What is the Subclass of Class Amphibia?

Subclass Lissamphibia

(has three orders of modern amphibians)

What are the three Orders of Modern Amphibians?

Gymnophiona (Caecilians/worm-like)

Urodela (Salamanders & Newts)

Anura (Frogs & Toads)

What are the main characteristics of Modern Amphibians?

Forelimbs with four digits

Cutaneous respiration (skin is thin & prone to desiccation)

Three chambered heart w. double circulation

Ecto & poikilo thermic (body temp varies on environment)

What are the main characteristics of the Order Gymnophiona?