Invertebrate Chordates and Fish

Presented to you by: Sanchita Agrawal, Priyanka Mangtani, Inga

Gurevich, Melody Chua

Part 1: Invertebrate Chordates

OBJECTIVES:

Examples

Evolution

Body Structure

Nutrition/Digestion

Transportation

Circulation

Reproduction

Water Balance and Excretion

Nervous System

Examples:Species Names:

Ciona intestinalis

Oikopleura

Branchiostoma (Amphioxus).

Main Subphylums

Urochordata – marine subphylum of chordates

Sea squirts (eg. Ciona), pelagic forms (eg. Oikopleura)

Cephalochordata – marine subphylum of chordates

- lancelets

Urochordata & Cephalochordata

Evolution

“Explosion” of invertebrate evolution in the lower Cambrian period (Beginning 570 million years ago)

- lasted 10 million years. - Melting glaciers => more water/places to live

Retinoic acid (a vitamin A-deirved morphogen) a possible component for their evolution.

=> too much or too little of it during embryo development could lead to mutations => evolutionary change

Evolved from lanceletsNotochord ( a cartilaginous rod along the back)No jaws

Image

At some point…

At some point in the invertebrate chordate life they have…

• A flexible, fibrous notochord that gives support.

•A hollow dorsal nerve cord in the back.

•Gill slits in the pharynx (throat area).

•Muscular tail which prolongs past the anus. (for locomotion and balance).

Structural Support

Urochordata Endoskeleton

Cephalochordata Endoskeleton

Endoskeleton- an internal skeleton made of bone or cartilage.

Nutrition and Digestion

Urochordata are filter feeders.

•1.) Water enters into the incurrent siphon

•2.) It goes to the slits in the pharynx

•3.) Food filtered by the pharynx moves to the stomach

•4.) Undigested moves to anus•5.) And exits through excurrent siphon.

Nutrition and Digestion

Cephalochordata are also filter feeders.

• 1.) Water is drawn by cilia into the mouth.

•2.) It moves to the pharynx.

•3.) The pharynx traps food particles from the water.

•4.) Food enters the intestine for digestion

•5.) The water leaves through atriopore. (An opening in the body).

Respiration

-Uses Pharyngeal pouches-portion of the digestive tract which is between the mouth and the esophagus

-Pouches have slits and evolved first into filter feeding structures and later into gill chambers

-Gill chambers help in respiration

Excretory System-Food particles in the water are trapped as the water passes through slits in the pharynx

-Water leaves the body through an opening called an atriopore

-Excretion occurs through paired kidneys

-Ex: Lancelets

Reproduction-Sexual

-Most Invertebrate Chordates reproduce sexually

-Majority lays eggs instead of bearing live young

-Few give birth to live young

Reproduction-Asexual

-Chordates in the phylum Urochordata reproduce asexually

-Invertebrate chordates are hermaphrodites

-Sperm and eggs are released through the excurrent to the surrounding water.

-External fertilization in the water

-Ex:Tunicates

Circulatory System

Urochordates

Open circulatory system

Cephalochordata

Nerve net

It can sometimes depend on the animal

• Hydra

• Flatworm

Higher invertebrates have more complex systems.

Annelids, arthropods, mollusk

• Ex: insects have compound eyes

Nervous System

Urochordata

Adults have neither notochord or dorsal tubular nervous system

Cephalochordata

Dorsal nerve chord

Notochord

• adulthood

Nervous System Subphylum

Invertebrates Nervous SystemHollow dorsal nerve chords Just above the notocord.

• brain

- Nerves connect internal organs, muscles, and sensory organs.

Part 2: FishOBJECTIVES:

Examples

Evolution

Body Structure

Nutrition/Digestion

Transportation

Circulation

Reproduction

Water Balance and Excretion

Nervous System

Unique Characteristics (for both

invertebrates and fish)

Examples

Pike - World’s first known chordate- large carnivorous, bony fish

- genus Esox in the family Esocidae.

More ExamplesLampreys

(Cephalaspidomorphi)

- Jawless fish

- No paired fins

- No scales

- Sharks, Rays, Skates, and Ratfishes (Chondrichthyes)

- Jaws & paired fins

- Cartilaginous skeletons

- Unique Scale Covering

- Ray-finned Fish (Actinopterygii)

- Jaws & paired fins

- Fins supported by rays

More Examples Continued…

- Lobe-finned Fish (Sarcopterygii)

- Fins supported by main aixis of bone.

- Lung fishes and coelacanth

Hagfishes (Class Myxini) – • Elongated, eel-like

bodies• No vertebrae• Jawless Fish• No true fins

CoelecanthCoelacanth

“living fossil”

A combination of 2 different types of fish: cartilaginous and bony fishes

• Evolutionary link

IMPORTANT: Has 4 muscular, limb-like fins underneath body; uses like legs to perch/support itself on ocean bottom.

- Lungfish

Coelecanth

Evolution - Fish: the first vertebrates.

- Example: Myllokunmingia, found from fossil deposits in China.

-Earliest fish- lampreys and hagfishes- Ordovician period

- jaws- => major advancement

- Earliest jawed fishes were covered in bony armor b/c of strengthening predatory race. => - ---

- Placoderms => extinct

- Jawed fishes that survived became: Chondrichthyes (cartilaginous fishes) Osteichthyes (bony fishes).

Symmetry & Body Cavity• Bilateral Symmetry

CoelomateÞ Muscle movementÞ body complexityÞ blood vascular system

Hagfish and Lamprey

Hagfish have endoskeleton.

(An internal support structure that consists of cartilage.)

Instead of having a jaw they have tooth-like projections that are used to pull food.

Lamprey have an Endoskeleton

Also are jawless.

Structural support continuedSharks, Rays, Skates, Ratfish

Endoskeleton

Ray-finned fish

Endoskeleton

Lobe-finned fish

Endoskeleton

Digestion and Nutrition for HagfishScavenger hunters that feed on dead or dying fish or

invertebrates

• Attach to prey

• Gets inside the prey

• With rasping tongue eats the inside of the prey

• They don’t have a true stomach

• Food travels form the esophagus to the straight intestine.

Nutrition and Digestion for Lampreys Parasitic

Feed on body fluids of hosts.

Attach to the body

Cut flesh with their tongues

Digestion for sharks, Rays, Skates, Ratfish

Most are carnivores

Some are scavengers

Enters through mouth

Travels to the stomach

Mush enters the intestine

DigestionFor Ray-finned Fish

Carnivores

Enters the mouth

Enzymes in stomach break it down.

For Lobe-finned Fish

Carnivores

Enters the mouth

Enzymes in stomach break it down.

circulatory systemAll fish have closed circulatory system

Has four hearts

• Brachial heart

• Partal heart

• Cardinal heart

• Caudal heart

Circulatory system

But hagfish have an intermediate one. Both a closed and an open one.

Fish have a two chambered heart

Closed systemProcess

Blood is pumped by the heart

Moves through arteries to the capillaries in the gills

There it exchanges carbon dioxide for oxygen.

Blood moves through body tissues.

Then back to the heart in veins.

Respiration

Extract oxygen from water & transfer it to blood stream

Need specialized gills which allow for rapid gas exchange

Gills are supported by four sets with filaments

RespirationCountercurrent flow-water flows across the gill

filaments in a direction opposite to the blood flow

Causes more oxygen to diffuse into the blood

Excretory System

Kidney filters dissolve chemical wastes from blood.

Kidney’s help regulate water and salt balance

Water is lost through osmosis

Reproduction-Bony FishEggs produced by ovaries and sperm are produced by

testes in the male

External Fertilization

High mortality rates among the eggs cause fish to lay a large amount of eggs to ensure some survive.

Some bear live young

Reproduction-Cartilagenous Fish

Internal fertilization using claspers-pelvic fins

Lay eggs after fertilization

Eggs hatch and are mini versions of adults

Some babies are born live

No parental care after birth/hatching

Reproduction-Jawless FishExternal Fertilization

Larvae resemble an invertebrate chordate

Larvae become adults

Nervous SystemThe nervous system is organized around the brain of the fish

The brain has different regions and eachofteh different regions do a different job.

• Ex: vision, smell, body movements, etc.

They have great sense of smell and taste

Nervous System Cont.

Eyes on both side of body

• Large, no eyelid.

• Retinas

• Large pupils

Inner ear, no outer ear opening.

Lateral line system

Nasal sac

Electrical Current

Example: HagfishPrimitive nervous system

Schreiner Organs

• Epidermis

• Pharynx

• Resemble taste buds

Did You Know….?- About 99% of the animals in the world are invertebrates?

-They are usually darker color on the top and lighter on the bottom to protect them from predators/enemies.

- Their body shape is streamlined to allow it to move through water more rapidly.

-They can change their color in an instant with color and reflective cells in their pigmentation!

-Scales protect the fish and reduce the friction while they swim.

-Fish are very diverse species…- Size range from 1 inch to 16 feet long!!!- They can be almost any color in nature

Works Cited

“Atlantic Hagfish” Sea and sky. 2009. Sea and Sky. 04 Apr. 2009. <http://www.seasky.org/deep-sea/atlantic-hagfish.html.> "Coelacanth." UXL Encyclopedia of Science. Ed. Rob Nagel. Vol. 3. 2nd ed. Detroit: UXL, 2002. 508-511. Gale Virtual Reference Library. Gale. VERNON HILLS HIGH SCHOOL. 7 Apr. 2009 <http://go.galegroup.com/ps/start.do?p=GVRL&u=vern39182>. “Hagfish.” Aquatic Community. 2006. Aquatic Community.com. 04 Apr. 2009. <http://www.aquaticcommunity.com/mix/hagfish.php.>  "Hagfish." Encyclopædia Britannica. 2009. Encyclopædia Britannica Online. 02 Apr. 2009 <http://www.britannica.com/EBchecked/topic/251522/hagfish>. Hine, Robert. "Chordata." The Facts On File Dictionary of Biology, Fourth Edition. New York: Facts On File, Inc., 2005. Science Online. Facts On File, Inc. http://www.fofweb.com/activelink2.asp?ItemID=WE40&SID=5&iPin= FDBF0554&SingleRecord=True (accessed April 7, 2009).

"Invertebrate Nervous System." Neuroscience for Kids. 12 Apr 2009 <http://faculty.washington.edu/chudler/invert.html>. “Lobe-Finned Fishes.” Natural History Notebooks. Canadian Museum of Nature. 23 Mar. 2009. 05 Apr. 2009. <http://www.nature.ca/NOTEBOOKS/ENGLISH/lobefish.htm.>  Marlétaz F, Holland LZ, Laudet V, Schubert M. Retinoic acid signaling and the evolution of chordates. Int J Biol Sci 2006; 2:38-47. Available fromhttp://www.biolsci.org/v02p0038.htm  "Nervous System - Evolution Of Invertebrate Nervous Systems." 12 Apr 2009 <http://science.jrank.org/pages/4595/Nervous-System-Evolution-invertebrate-nervous systems.html>. "Paleontology." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. Vol. 4. 4th ed. Detroit: Gale, 2008. 3178-3185. Gale Virtual Reference Library. Gale. VERNON HILLS HIGH SCHOOL. 7 Apr. 2009 <http://go.galegroup.com/ps/start.do?p=GVRL&u=vern39182>. "Pike." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. Vol. 4. 4th ed.Detroit: Gale, 2008. 3339-3340. Gale Virtual Reference Library. Gale. VERNON HILLS HIGH SCHOOL. 7 Apr. 2009 <http://go.galegroup.com/ps/start.do?p=GVRL&u=vern39182>. Postlethwait, John, and Janet Hopson. Modern Biology. Austin: Holt, Rinehart and Winston, 2006. Print. Schlager, Neil. Grzimek's AnimalLife Encyclopedia Fishes 1. 2nd ed . 2003. Shark Diet and Drinking.” Enchanting Learning. 1999. Enchanting Learning Software. 05 Apr. 2009. <http://www.enchantedlearning.com/subjects/sharks/anatomy/Diet.shtml.> “Shark Digestion.” Enchanting Learning. 1999. Enchanting Learning Software. 05 Apr. 2009. <http://www.enchantedlearning.com/subjects/sharks/anatomy/Digestion.shtml.> "The Invertebrate Animals." 15 Jan 2009. 12 Apr 2009 <http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/I/Invertebrates.html>.