EVERYTHING YOU ALWAYS WANTED TO KNOW ABOUT: INVERTEBRATES

WHAT MAIN CHARACTERISTIC IS SHARED BY ALL VERTEBRATES?

IF YOU SAID BACKBONE, YOU ARE CORRECT! VERTEBRATES ARE MEMBERS OF THE PHYLUM CHORDATO - (from the name notochord)also called Chordates

CHORDATE Characteristics: At some time in life they have: NOTOCHORD, or nerve cord - a rod like structure that supports back.

Your NOTOCHORD is your spinal cord - It’s the connection between the brain and the nerves

SOME VERTEBRATES have backbone made of CARTILAGE (connective tissue - softer than bone but still strong!

Backbones run down center of back. Made up of VERTEBRAE lined up in a row. Joints between vertebrae give you flexibility

EACH VERTEBRAE HAS A HOLE IN IT THAT THE SPINAL CORD GOES THRU - like fingers fit into rings

COW BACKBONE FISH

The backbone is part of the ENDOSKELETON (internal skeleton). It’s job: SUPPORT PROTECT GIVES BODY SHAPE A PLACE FOR MUSCLES TO ATTACH

Endoskeleton also includes the skull(protects brain as u see in my picture), ribs(protects organs), arm and leg bones (help you move)..but YOU already knew that!

How can you tell the difference between types of vertebrates? BODY TEMPERATURE Fish, amphibians, reptiles are ECTOTHERMS - body temp. changes with environment. Birds and mammals are ENDOTHERMS - body controls temp by controlling internal heat it produces.

Chordates have slits in their throat called PHARYNGEAL One last fact about vertebrates: Chordates have slits in their throat called PHARYNGEAL Most other vertebrates have their pharyngeal slits disappear before birth. PHARYNX

Fish keep these slits all their lives as part of their gills. PHARYNGEAL SLITS Fish keep these slits all their lives as part of their gills.

FISH

HOW DO FISH USE THEIR GILLS? WHAT ARE THE 3 GROUPS OF FISH?

FISH: vertebrates that live in water fins for movement ectothermic gills to breathe have scales - overlapping plates that protect skin

Fish swim along, open their mouth & take in H20 OBTAINING O2 Fish swim along, open their mouth & take in H20 The H20 moves thru mouth to gills GILLS: feather-like structures - red in color due to blood vessels in them.

H20 flows over gills O2 moves into blood C02 flows out into H20

Like all vertebrates, fish have a closed circulatory system Like all vertebrates, fish have a closed circulatory system. The heart pumps blood in a loop: HEART GILLS BODY HEART

FINS: thin membrane stretched across bony supports MOVEMENT FINS: thin membrane stretched across bony supports

Well, not like this…..more like…. FEEDING FISH have highly developed nervous systems and sense organs to help in capturing food and avoiding predators Well, not like this…..more like….

Their eyesight is better than yours (remember there is less light under water) Sharks can smell and even taste a tiny amount of blood - as little as one drop- in 115 liters of water! That is 57.5 two liter sodas!

AND some fish have taste organs in the most unusual places AND some fish have taste organs in the most unusual places. Catfish have taste organs on their whiskers!

Some fish like the barracuda have sharp teeth for stabbing food FEEDING Some fish like the barracuda have sharp teeth for stabbing food

Others, like trout have short blunt teeth for gripping & crushing insects

Filter Feeders like the Basking Shark and Manta Ray use comb-like structures on their gills to filter tiny plants and animals from the water.

Fish Reproduction Most fish have external fertilization: as female releases eggs, male spreads a cloud of sperm over them. Some fish like guppies and sharks have internal fertilization: when the eggs are mature enough to live on their own, female gives birth.

Biologists classify fish into 3 groups: Jawless Fishes Bony Fishes Cartilaginous Fishes They are grouped according to their mouth structure and type of skeleton

JAWLESS FISH

skeletons made of cartilage Jawless Fish No scales skeletons made of cartilage one fin (no pairs of fins) jawless mouth scrapes, stabs and sucks to get food Lampreys are eel shaped parasites-use sharp teeth and suction-cup mouth to feed

CARTILAGINOUS FISH

Skeletons made of cartilage Have jaws and pairs of fins CARTILAGINOUS FISH Sharks, Rays, Skates Skeletons made of cartilage Have jaws and pairs of fins Pointed, tooth-like scales cover bodies - rougher than sandpaper Carnivores Rays and Skates live on ocean floor - filter feeders - east mollusks, crustaceans, small fishes

CARTILAGINOUS FISH - Sharks Streamlined bodies for quick movement Mouth on bottom part of head Jagged teeth arranged in rows - 1st couple rows are for feeding - remaining rows are replacement teeth. If a tooth is lost, one from next row moves up (NO DENTURES EVER NEEDED!) Sharks

SHARK TEETH ROWS

CARTILAGINOUS FISH - Sharks Swimming or currents move water over gills Spend most of time hunting for food - will attack anything that smells like food. Poor eyesight - that is why they swallow strange objects at times.

BONY FISH

BONY FISH Most familiar fish are bony fish: trout, tuna, flounder, salmon, goldfish, etc. Covered with scales Pocket on each side of head that holds gills - flap over gills opens to release water

Swim Bladder and Buoyancy BONY FISH Swim Bladder and Buoyancy Fish neither sink or float. They have an organ called a SWIM BLADDER - sac that stabilizes body at different depths. It contains O2, nitrogen & CO2...

Swim Bladder and Buoyancy ...if the gas is less the fish sinks lower - if it is more the fish moves higher in the water. The change in the gas volume affects the Buoyancy Force - force that water exerts upward on any underwater object LESS THINK BALLOONS! MORE

Bony Fish Diversity Make up 95% of all fish species Live in salt and fresh water Some live in deep water and some in shallow