Phylum Chordata A Chordate is an animal that has 4

specific characteristics during their life cycle: 1- Dorsal, hollow nerve cord 2- Notochord – a long supporting rod

that runs through the body below the nerve cord

3- Post anal tail 4-Pharyngeal pouches (gill slits)

1- A Dorsal, Hollow Nerve Cord This is a sheath of large nerve cells These nerve cells are somewhat like

stem cells in they may play an important role in other nerve cells that develop Example: certain motorneurons are

affected by the absence of these cells in embryonic development

In higher organisms, the actual “spinal cord” is surrounded by this hollow covering.

2- A Notochord The notochord is a strong structural

part of the organism It is located dorsally from the gut

(endoderm and coelom) It is made of cartilage or bone It is the spine, or vertebral column

3- A Post Anal Tail

Post means it is located posterior to the anus, or behind the anus

It is an extension of the notochord, and made of cartilage or bone

4- Pharyngeal pouches These are located at the pharynx, or

throat, of a chordate They develop into the gills of fish and

juvenile amphibians In aquatic reptiles, birds and

mammals, they close during embryonic development and become the throat, while the nasal passageways develop

Subphyla of the Phylum Chordata

The Nonvertebrates: Sub Phylum

Urochordata tunicates or “Sea Squirts”

Sub Phylum Cephalochordata – lancelets

These are very simple chordates without spines

All are aquatic

Subphyla of the Phylum Chordata The Vertebrates

Sub Phylum Vertebrata– cartilaginous and bony fish, amphibians, reptiles, birds, mammals

These are chordates with spines of cartilage or bony tissue

Vocabulary Body temperature control:

Ectotherm – animals that rely on behavior and interactions with the environment (Cold-Blooded)

Endotherm – animals that generate their own body heat and control temp. from within (Warm-Blooded)

Vocabulary

Egg to Juvenile Method:

Oviparous – Eggs hatch outside the female body

Ex: Most Fish

Ovoviviparous – Eggs develop inside the female body and the young are live-born Ex: Some Sharks)

Viviparous – bear live young that are nourished directly by the mother’s body as they develop.

Ex: Whales, Otters

Vertebrates – Agnathans (jawless fish) Examples: Lamprey; Hagfish Body Plan: snake-like, no scales, no

paired fins, no true teeth or jaws

Skeleton Type: fibers and cartilage

2 chambered Temperature control: ectotherm

Respiration: gills Reproduction: sexually-external/

internal fertilization (oviparous)

Importance: lamprey are parasites and hagfish are decomposers that feeding on dead or decaying fish)

Vertebrates – Class Chondrichthyes

Examples: Sharks, Rays, Skates Chondros (Gk = cartilage)

Body Plan: large curved tails, torpedo-shaped body, pointed snout, moveable jaw, placoid (rough as sandpaper)scales

Skeleton Type: cartilage

2 chambered Temperature control: ectotherm

Respiration: gills Reproduction: sexually- external/internal fertilization

(oviparous/ovoviviparous/some viviparous)

Importance: predators in the food chain

As the front row of shark teeth are worn out, new teeth are continually replacing them. A shark goes through 20,000 teeth in its lifetime!!

A skate is shown in the top picture; a stingray below

Vertebrates – Osteicthyes (bony fish)

Examples: goldfish, perch, bass, trout Body Plan: lateral line (use this to sense motion of other

fish nearby), swim bladder (internal, gas-filled organ that adjusts buoyancy), scales

Skeleton Type: hard, calcified tissue called bone 2 chambered Temperature control: ectotherm

Respiration: gills Reproduction: sexually-

external fertilization(97% are oviparous)

Importance: prey in the food chain, fishing industry

Bony Fish Types Saltwater

Strictly live in water with dissolved salt content near seawater, about 35 ppt in the open ocean

Must regulate the loss of freshwater out of their bodies as natural osmosis and diffusion seek to balance salt concentrations within and surrounding their bodies

Ex: marlin, mullet, snapper; flounder Brackish water

Require salinities between 35 ppt and freshwater Many marine fry are hatched in brackish water then migrate to

open oceans as they mature Ex: fry; sheepshead, croaker

Freshwater Strictly live in freshwater Must regulate the increase of freshwater into their bodies as

natural osmosis and diffusion seek to balance salt concentrations within and surrounding their bodies

Ex: blue catfish; bluegill, hybrid bass

More Types of Fish

Catadromous These fish hatch in marine waters and then migrate

into freshwater to spend adulthood They return to marine waters to spawn Ex: Eels are the most common fish to do this, and

the Sargasso Sea, near the southern part of the Atlantic Gyre, is their famous spawning ground

Anadromous These hatch in freshwater and then migrate into

marine waters to spend adulthood They return to freshwater to spawn, and then usually

die Ex: Salmon, shad, smelt and sturgeon are examples.

Things you must know: Fish External Anatomy

All fins Lateral line Scale Type

Fish Internal Anatomy Fish Organ Systems

Fish Morphology Body Shape that indicates ecological niche

Fish Behaviors Mating, Territoriality, Parenting

Identifying and “Keying Out” Fish What class are they in

Vertebrates - Reptilia Examples: snakes, lizards, turtles & tortoises, crocodiles

Body Plan: dry, leathery skin, thick scales made of karatin (smooth or rough), terrestrial, amniotic eggs (shell & membrane so egg can develop out of water)

Skeleton Type: hard, calcified tissue called bone 3 chambered except crocodiles with 4 chambered

Temperature control: ectotherm Respiration: lungs

Reproduction: sexually-

internal fertilization – eggs laid on land(most oviparous/ some ovoviviparous)

Importance: control rat populations, medical use/research, clothing industry

Snakes are carnivorous and stretch their jaws to consume their prey whole.

Turtles make a nest and lay their eggs on land.

The sex of a crocodile is determined by temperature, with

males produced at 88 F, and females produced at 80 F and 93 F.

Loggerhead TurtleCaretta caretta- one of the largest, most abundant sea turtles

Kemp’s Ridley TurtleLepidochelys kempii -

Endangered, smallest of sea turtles, feeds mostly on crabs

Leatherback TurtleDermochelys coriacea -

largest turtles on Earth, growing up to seven feet long and exceeding 2,000 pounds

Sea TurtlesBodies enclosed in a carapace (top shell) that is fused to their backbone

Green turtle is hunted mostly for meat and cartilage for turtle soup

TEDS – turtle exclusion device mandated by US government for shrimp nets

Cannot retract their head into their shell

Legs are modified into flippers for swimming

                                   

Migrate long distances to reproduce

7-8 speciesMost live in warm waters

Do not have teeth, but have strong jaws

NestingVery little is known why sea turtles nest on some beaches, and not on others

Most females return faithfully to the same beach each time they nest

Females nest usually at night

“false crawl” – occurs when female turns back and decides not to nest

Females lay 100-160 eggs in a nest that hatch about 60 days later

Females appear to “shed” tears as they lay, secreting salt that has accumulated in her body

Covers with rear flippers and disguises the nest

Incubation & Emergence About 60 days The hotter the sand, the faster they hatch

Warmer sand – more females

Cooler sand – more males

Hatchlings use a temporary, sharp egg-tooth called a “caruncle” to break open the shell

Caruncle then falls off

Digging out of the nest is a group effort that takes days

Emerge from nest in a group

Orient themselves to the brightest horizon

Only about 1 in 1000 survives to adulthood

Vertebrates – Amphibia (“double-life”)

Examples: frogs, Toads, newts, salamander As larvae usually live in water and as adult live on land Body Plan: moist skin with mucus glands, lack

scales/claws, undergo metamorphosis Skeleton Type: hard, calcified tissue called bone 3 chambered Temperature control: ectotherm Respiration: young=gills adult=lungs Reproduction: sexually-

external fertilization(oviparous) or internal (salamanders)

Importance: control insect populations, medical/ pharmaceutical use, food source (frog legs) in India/Asia

Frog Metamorphosis

Vertebrates – Aves (birds) Examples: chickens, penguins, cardinals, ostrich Body Plan: feathers of protein/keratin (flight/warmth),

two legs covered in scales, front limbs modified into wings, thin hollow bones (helpful for flying)

Skeleton Type: hollow, calcified tissue called bone 4 chambered Temperature control: endotherm (can generate own body heat)

Respiration: lungs, includes passageways of air through air sacs Reproduction: sexually-

internal fertilization - oviparous Importance: control insect populations, food source, clothing,

bedding, hunting purposes

Aquatic Birds have special adaptations…

Their feathers are highly resistant to being wetted They usually have higher oil production than other

birds from glands at the base of the tail The oil is applied to the feathers during preening

Preening is birds grooming activity; they run their beak through their feathers to straighten and comb them

During preening oil is spread lightly over feathers to help keep them water resistant

Dry feathers Keep birds warm when in aquatic sites Are easier to use for flight (think about a paper

airplane that is dry vs. one that is wet!)

More special adaptations… Aquatic birds also have special

appendages… Feet are webbed for swimming Legs may be longer to wade in water Long toes spread out to distribute weight in mud Beaks are modifications like the following:

for grasping wet, slippery prey Hooked tips on eagles The huge “baskets” of pelicans, spear-like points in herons, cranes and egrets filters of flamingos Beaks modified into bills for duck- and goose-like

creatures for sifting worms and arthropods from mud, or for catching fish underwater

MARINE BIRDS

Class Aves

Endotherms – warm-blooded

Covered with waterproof feathers to conserve body heat

                           

Most can fly

Nest on land, many forming huge colonies

Have webbed feet

http://video.nationalgeographic.com/video/index.html

Feed mostly at sea Worldwide distribution Only 3% of total bird population High metabolism – eat up to their

body weight a day

Penguins Native to Southern Hemisphere.

Most northerly population lives in Galapagos Islands.

The bird most fully adapted for sea life

flightless

Great swimmers Adapted for cold by storing fat

under skin

Dense feathers hold in body heat

18 species Most are native

to Antarctica

Establish breeding colonies, with some mating for life

Emperor PenguinLargest

45 inches tall

                                    

Pelicans Have a pouch

below their beak.

Most scoop fish from the water

Brown PelicanAlmost extinct because of pesticide pollution

Nest in large, messy, twiggy nests along the coast

Brown Pelican plunges in the water to catch their food. If they don’t catch it directly, the shock stuns the fish

Gulls Largest family of seabirds Predators and scavengershttp://video.national

geographic.com/video/

1. Shore birds2. Water birds3. Sea birds

3 Categories of Marine Birds

1.ShorebirdsWading birdsLive mostly inland: estuaries and marshes

Plovers

Sandpipers

2.Water Birds Live in coastal and continental

interiors, but require water for feeding and nesting

Ducks

Loon Cormorant

3.Sea Birds Live on and around the sea

Albatrosses Nest on land, live at sea Wingspans can reach 11 feet.

http://video.nationalgeographic.com/video/index.html

Arctic Terns Have the greatest migration of any

bird. They venture from pole to pole every year- a voyage of 22,000 miles.

Hazards for Sea BirdsPlastic debris- ingest plastic materials because it fills the stomach, but lacks nutrients and cannot be passed.

Oil slicks saturate the feathers, destroying the ability to insulate, let alone be able to fly. The loss of insulation alone can be fatal

The greatest danger to seabirds is…. rat and mouse invasions. The mice consume the bird’s eggs in huge numbers, causing significant bird population declines on some Pacific Islands.

http://player.discoveryeducation.com/index.cfm?guidAssetId=5EB7F6AC-44B0-4E2E-A4CC-1C9411BE3ED7&blnFromSearch=1&productcode=US

Vertebrates - Mammalia

Examples: cats, whales, gorillas, zebras, humans

Body Plan: mammary glands (produce milk to nourish the young), have hair, breathe air, bear live young

Skeleton Type: hard, calcified tissue called bone

4 chambered

Temperature control: endotherm (can generate

own body heat)

Respiration: lungs

Reproduction: sexually-

internal fertilization (viviparous) Importance: food, hunting, clothing, medical research, pets

Mammalia Reproduction Diversity Monotreme – “egg-laying

mammal”; like reptiles except after eggs hatch the young is nourished by mother’s milk Only 3 species exist: duckbill

platypus, 2 spiny anteaters

Marsupial – bear live young that complete their development in an external pouch Kangaroos, koalas, wombats

Placental – nutrients, O2, CO2, wastes are exchanged b/n embryo and mother through placenta Elephants, rabbits, humans