Aquatic Life - Vertebrate Animals

Aquatic Life - Vertebrate Animals Aquatic Life - Vertebrate Animals

In this unit we will discuss characteristics of aquatic animals categorized as vertebrates (animals with backbones) beginning with fish.

Summaries = Purple Underlined = Vocabulary

Photo Credit: Ken Knezick - Island Dreams Image

Chordate CharacteristicsChordate Characteristics At some stage in their

development, all chordates share four main characteristics…

1. A dorsal, hollow nerve cord will later connect the brain to the rest of the body (internal organs, muscles, and sense organs in advanced organisms).

2. The notochord is a long supporting rod that runs through the body just below the nerve cord (it will be replaced by the backbone in advanced vertebrates).

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Nerve Cord/NotochordNerve Cord/Notochord

The nerve cord becomes the spinal cord.

The notocord becomes your backbone.

Think about how your brain communicates to the body; through the nerve cord.

If that is cut, then an organism is paralyzed!

(Your spinal cord runs here)

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Chordate Characteristics Cont. Chordate Characteristics Cont.

3. Pharyngeal pouches are found in the throat region and will develop into gills or other structures such as jaws or inner ear in some organisms.

4. A tail is retained (kept) by most chordates throughout their lives.

Humans go through a stage in as a fetus where we have a tail for about two weeks.

http://www.biologycorner.com/bio2/notes33.html

Human fetus early in gestation (after sperm and egg unite) at about 2 – 4 weeks.

Sometimes the human is born with the tail and doctors will just remove it with a laser and cut it off.

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Traits of All ChordatesTraits of All Chordates

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Sketch & Label

Introduction to VertebratesIntroduction to Vertebrates Kingdom Animalia

Phylum Chordata Subphylum Vertebrata (animals that have

backbones) 2 subphylums of non-vertebrate chordates that

do not have backbones ()1. Subphylum Urochordates - Tunicates (sea squirts)2. Subphylum Cephalochordata (lancelets)

TunicatesTunicates Scientists believe that

vertebrates evolved from ancient marine organisms like tunicates and lancelets.

These chordates are soft bodied marine organisms; they have a nerve cord but NOT a backbone.

Tunicates are filter feeding; go through a youth larval stage before their adult stage (below).

http://www.aboututila.com/Reviews/Charlie-Johnson/Photos/Bluebell-Tunicates.jpg

LanceletsLancelets Lancelets are small, fish

like creatures that live on the ocean floor.

They have a closed circulatory system (blood vessels), but no true heart and are thin enough that they filter oxygen straight through their skin. http://upload.wikimedia.org/wikipedia/commons/

thumb/a/a0/Branchiostoma_lanceolatum.png/180px-Branchiostoma_lanceolatum.png

Subphylum Vertebrata Subphylum Vertebrata Members of subphylum vertebrata have an

endoskeleton (an internal skeleton) which can support large body and grows as the animal grows.

The skeleton includes a backbone which is a series of bones known as vertebrae that surround and protect the spinal (nerve) cord

Vertebrates have a distinct skull attached to the end of the backbone.

Vertebrates also have a well developed brain and sensory organs located in the skull (Cephalization).

http://trc.ucdavis.edu/biosci10v/bis10v/week10/brainevolution.gif

Timeline - Vertebrate EvolutionTimeline - Vertebrate EvolutionAbout Age Animals

550 million years ago Ordovician Period First vertebratesjawless fishes

400 million years ago Devonian Period"Age of Fishes"

Acanthodiansjawed fish

350 million years ago Carboniferous Period (and Permian)"Age of Amphibians"

Amphibians

240 million years ago Triassic PeriodJurassic Period"Age of Dinosaurs"

reptiles appeareddinosaurs dominated the land for 150 million years - sauropods, theropods, etc..

60 million years ago Tertiary Period"Age of Mammals"

Dinosaurs extinctMammals appeared

340,000 years ago Quaternary period Humans appeared

Vertebrates adapted into 2 different ways to regulate body temperature.

Ectotherms have a body temperature that matches the external environment.

ecto = outside and therm = heat

EX fish, amphibians and reptiles

Endotherms can maintain a constant internal body temperature (using energy and adaptations such as hair and fat layers).

Endotherms, therefore require more food than an ectotherm.

endo = inside birds and mammals

Characteristics: Temperature Characteristics: Temperature

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Vertebrates have a closed circulatory system.

This means that all blood flow is contained within blood vessels.

They also have a multi-chambered heart pumps oxygen and nutrients to the body.

Characteristics: Circulation Characteristics: Circulation

Oviparous – eggs hatch outside the mother’s body and the yolk provides nourishment EX chickens, turtles

Ovoviviparous – eggs are held inside and hatch in the mother’s body and then young are born alive; yolk = nourishment EX sharks

Viviparous – young develop inside mother’s body and gets nourishment from the mother EX humans, dolphins

Characteristics: Reproduction Characteristics: Reproduction

http://courses.washington.edu/vertebra/451/photos/dogfish_embryo_ventral.jpg

Fish - ReproductionFish - Reproduction

Fish can have internal or external fertilization to reproduce.

Fish produce many more eggs (oviparous) than the environment can support.

Only the fastest, strongest and best are adapted survive.

http://www.ufz.de/data/5460

Fish get rid of waste products in the form of ammonia. Fish use a stomach, intestines, and kidneys to filter the wastes

from the blood which then is excreted through the anus.

Fish - ExcretionFish - Excretion

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Introduction to FishIntroduction to Fish Our first group of vertebrates that we will discuss

will be fish - covered by more than two-thirds of water, Earth displays a huge variety of fish.

Fish (not “fishes”) are aquatic organisms that can survive only in water.

http://www.mikelevin.com/ColorfulFishBig.jpghttp://www.noeticart.com/clipart/GreenAngler.jpg

Jawless FishJawless Fish Class Agnathans As their name implies, these fish

have no true teeth or jaws. Lack paired fins and are shaped

more like worms than other fish. These are the only vertebrates to

retain (keep) a notochord throughout their life.

Lampreys – parasites that feed on host’s body fluids; have no paired fins

Hagfish – scavengers

http://www.zoo.ufl.edu/courses/vertzoo/Images/Bonyfishlab2/Lamprey.jpg

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Class Chondrichthyes This group of fish includes sharks

and their relatives sting rays. Their skeletons made of flexible

cartilage (like our noses) with tooth-like scales covering skin that feel like sandpaper.

They have stiff fins and their gills do not have covers.

These fish are adapted to deep-sea life.

Some are carnivores while others are filter feeders.

Internal fertilization with live birth. (ovoviviparous ).

Sharks & RaysSharks & Rays

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Class Osteichthyes These fish have skeletons

made of a calcified tissue called bone.

In many fish, the female lays the eggs and the embryos in the eggs develop and hatch outside her body (oviparous).

These eggs are soft-shelled eggs.

Flexible fins are used for movement.

Bony FishBony Fish

http://www.emill.com/emill_dynamic/image6in/puffer_fish.jpg

Ray-finned fish (the largest, most diverse group) are so called because of the thin bony spines, or rays, that help to form the fins.

Ray-finned fish have adapted to every kind of aquatic environment and evolved into thousands of species.

Bony Fish Subclasses – Ray-finnedBony Fish Subclasses – Ray-finned

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Fish - Adaptations for WaterFish - Adaptations for Water Fish are characterized by overlapping scales

that cover the skin to provide protection. These scales are coated in a slippery mucus to

reduce friction in the water and help them to swim faster.

Fish have paired fins to help steer and provide stability in the water (movement).

Fish have an internal swim bladder to allow them to move up or down in the water or remain at a given depth. Think of it as a thin balloon-like sac; with air the fish goes

up in the water, without air the fish sinks (not found in sharks).

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http://www.kentuckylake.com/fishing/fishfacts/pics/ext-anat.jpg

The lateral line system is a sense organ that detects vibrations and changes in the water pressure and alerts fish to movement of other organisms in the water.

Fusiform shape allows a fish to move through the water effectively; fish are tapered at both ends to increase speed through the water.

Cont. Adaptations for WaterCont. Adaptations for Water

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