bio

Elasmobranchs

Elasmobranchs

sharks, skates, rays, oldest and largest vertebrates

Agnatha

jawless fish: lamprey and hagfish

Chondrichthyes

cartilaginous fish (sharks, rays)

Osteichthyes

bony fish

Agnatha characteristics

-muscular circular mouth with rows of teeth -long cylindrical body-lack paired fins and scales

Hagfish

-feed on dead and dying fish-burrow in soft sediment-make slime for defense

Lamprey

-large portion of life in the sea, return to freshwater to breed-sucker like mouth for consuming blood, tissue and body fluids

Chondrichthyes and Osteichthyes characterists

-highly efficient gills-scales-streamline-paired fins-variety of jaw and feeding types-lateral line and sensory organs

Ratfish

-deep water-mouth with plate like grinding teeth-tiny tail-venomous spine-head clasper-no scales-skin flap covers 1 gill slit-fused jaw-heterocercal tail-fin rays (tiny support rods) in the fins

elasmobranch characteristics

-some travel up rivers -heterocercal tail-2 dorsal fins-carnivorous or planktonic-350 extant species-cartilage skeleton-paired fins-spongy cartilage snout-well-developed teeth with movable jaws -5 to 7 gill slits-male have claspers

Spiracles

opening on head used to bring water directly in for respiration without opening the mouth

Chondrichthyes Breathing

-ram ventilation-buccal pumping-spiracle breathing-obligation ram ventilators

Chondrichthyes scales

placoid scales made for drag and noise reduction

lateral line

a visible line along the side of a fish consisting of a series of sense organs that detect pressure and vibration.

Ampullae of Lorenzini

sensory organs in the head of cartilaginous fishes to detect electrical charges, important in detecting prey

shark liver

no swim bladder so large liver rich in oil

Demersal

live on the bottom

Neritic

Swim next to continental shelf

oceanic pelagic

swim in open blue water

people affect sharks

-disastrous fishing -fished for oil -skin is turned into leather -skin also used as sandpaper -fished for fin soup

Skates and rays

-dorsoventrally flattened bodies -spend much time on the bottom covered in sand -large flattened teeth -fleshy long whip-like tails -enlarged Pectoral Fins

skates

-dorsoventrally flattened body -have a fleshy tail without a spine -always lay egg cases -demersal and feed on molluscs -spiracles behind eyes -found at depths greater than 4000 meters

rays

-rays pectoral fins are expanded into wings and entire body is dorsoventrally flattened -long whip like tails, spines at the base of the tail with poison gland

manta ray

plankton feeder in mid-water; gill rakers used for filtering water

electric rays

have large electric organs on each side of head

claspers

-male shark -pair of organs between pelvic fins that transfer sperm -rolls of cartilage that become stiffened with calcium

Cloaca

females have a cloacal opening

Vivipary

live birth with placenta

Ovipary

egg laying

Ovovivipary

development of an embryo within an egg inside the mother's body but without the embryo receiving any nourishment from the mother

Osteichthyes characteristics

-gills for respiration -hinged jaws allow for a variety of different ways of feeding -homoceral tail

homocercal tail

symmetrical tail

lobe-finned fish

Fleshy, lobed, paired fins, which are joined to the body by a single bone

ray-finned

-may contain only spiny rays, only soft rays, or both -stiff and sharp -soft, flexible, segmented, and may be branched

Gill arch

Supports the structure of the gill

gill rakers

On the forward surface of the gill arch

gill filaments

trail behind the gill arch

operculum

covers gills and provides protection

swim bladder

used for buoyancy control

shark buoyancy

Large oil filled liver

Sharks

-Tend to sink when not in motion -Use pectoral fins to aid in lifting

ctenoid scales

thin flexible and overlapping scales in bony fish that have tiny spines

Cycloid scales

Thin, large, round, arranged in an overlapping pattern

Countershading

Ventral (belly) side is lighter than the dorsal side.

cryptic coloration

Camouflage; makes an organism difficult to spot.

disruptive coloration

bars or stripes that help break up the silhouette

Eye spot mimicry

Circular patterns near caudal fin -Confuses predator who are not sure where the head is

warning coloration

advertise themselves as dangerous

fuisform

Fast moving, predators, long, streamlined, very little flexibility

Compressiform

compressed from side to side, quick bursts of speed over short distance

Depression

Flattened top to bottom, live on bottom, slow, flap fins up and down

Filliform

Elongated, live in soft sediment, slow, slither

Pectoral fins

Side fins on fish

Pelvic fin

Underside of a fish

dorsal fin

top fin

Adipose fin

The fatty fin on some species of fish, on top

anal fin

an unpaired fin located on the underside of a fish posterior to the anus.

caudal fin

tail fin

Homoceral

Symmetrical

Heterocercal

asymmetrical

homocercal rounded

-large amounts of surface area allows sharp turns and quick starts -creates drag - fish tires easily

homocercal truncate

-allow short bursts of speed to escape predators or constant slow swimming -less drag -bottom dwelling fish

homocercal, forked

-constant swimming over long distances, reduces drag -open water fish -do not need speed to feed or for protection

homocercal lunate

-half moon shaped -fast moving -less drag, great acceleration, reduced maneuverability

Heterocereal tail

-medium speed -provides lift when no air bladder -reduced maneuverability

Swimming Patterns

-fish have an S-shaped pattern -bony fish fins are flexible and used for maneuverability -slower swimming species, forward movement is provided by pectoral fins -fins may be flexible and highly modified for camouflage

acquiring and processing food

-mouth structure reveals dietary preferences of fish -beak (fused teeth) allows for these fish to scrape algae and other organisms off of hard surfaces -tube like mouth to feed on corals -sharp teeth and wide mouth to capture prey

schooling

-possible for a group of smaller fish to appear much larger -harder for predators to capture any one fish

Territoriality

-fish maintain their territories normally by posturing to show their aggression -posturing can include raised fins, open mouth, darting

reproduction of fish

-hermaphroditic (possess male and female reproductive organs) -simultaneous hermaphrodites (have these structures at the same time) -sequential hermaphrodites (possess the structures at different times during life)

Types of Sequential Hermaphrodites

-Protogynous (female to male) -Protandrous (male to female)

Class Reptilia

reptiles

Class Aves

birds

Class Mammalia

mammals

Nekton

All organisms that swim actively in open water, independent of currents

Marine Reptiles

-air breathers -dry skin and scales -egg layers on land -cold-blooded

Ectotherm

an animal whose body temperature varies with the temperature of its surroundings -doesn't use energy -thrive in warm

Endotherm

An animal whose body controls and regulates its temperature by controlling the internal heat it produces

Homeotherm

an animal with a constant body temperature

poikilotherm

an animal whose body temperature varies with the temperature of its surroundings

sea turtles

-poikilotherms and ectotherms -breed at sea -internal fertilization -can have many males -breed every 2-4 years -return to land to lay eggs -lay 120 eggs

Sea Turtles Eggs

-soft and leathery -lay where they were born -incubation of 60 days -temperer determines the sex (cool is male)

turtle hatchling

-hatch in 2 months -wait until night to leave nest -head for water

Papillomavirus

virus that affects sea turtles

Sea turtle diet

-babies are omnivorous -adults are carnivores -green turtles are vegetarian

sargassum refuge

use seaweed as an area of refuge, rest, and/or food

Green Sea Turtle

-vegetarian -fat in body is green from diet -considers tropical nesting turtles -endangered

Leatherback

-largest sea turtle -feed on jellies -backward facing spines in mouth

Hawksbill Sea Turtle

tropical spices -feed coral, sponge

loggerhead

least vulnerable -eats crabs and mollusks

Turtle threats

-killed for eggs, meat, skin, shell -poached and over exploration -habitat destruction -fishing gear -climate change

sea snakes

55 species -found in Indian and Pacific Ocean -laterally flattened body with paddle like tail -3-4 feet -venomous

saltwater crocodile

found in estuaries, mangrove swamps, rivers, open ocean -eat all types of prey

marine iguana

-Galapagos -portion of life in water -dive to feed on sea weed and sea grass -most of day they are basking on shore -laterally flattened tails -limb bones -salt is expelled from cranial exocrine glands -blunt noses

Seabirds

feathers that cover the body are coated in oil from glandular secretions to waterproof -colonial nesters- near shore, cliffs, shrubs, and trees

Penguins

flightless with flipper like structure -Antarctica -layer of fat and trap air in the feathers to keep warm -share parenting responsibilities

marine mammals

-vertebrates -hair -make milk -torpedo like fusiform bodies to reduce drag -modified limbs for propulsion or steering -tails for propulsion and balance

Thermoregulation

-dense fur or blubber -countercurrent heat exchange -large body size -behavioral adaptations

counter current exchange

the transfer of heat between fluids that are flowing in opposite directions -transferred from arteries to veins

diving

-pinnipeds and cetaceans have large and complex blood vessel systems which serve to store oxygen -reduced heart rate -shunting of oxygen to vital organs