Test #1 Material

What is an animal?1. Mutlicellular, heterotrophic (get their own

food), eukaryotes2. Cells do not have cell walls3. Have nervous and muscle tissues4. Usually reproduce sexually

These are characteristics of MOST animals.

Reproduction1. Sperm + Egg => 2. Zygote (fertilized

egg) => 3. 8 cell ball

(cleavage)=> 4. Blastula (hollow

ball of cells) => 5. Gastrula

Evolution of AnimalsMost scientists agree

that the animal kingdom is:Monophyletic- came

from a common ancestor

Has branches where each adaptation comes in

Parazoa “beside the animals”Has no true tissuesSponges

Eumetazoa

2 branches based on symmetry

Radial ex.) jellyfish and

relatives has a top and a

bottom no head or rear no left or right

Bilateral Ex.) all other

animals Has a top and

bottom Has a head and a

tail Has left and right

sides

Acoelomates

Evolution of body cavities

More complex animals 

Started without body cavitiesEx. Flatworm 

Acoelomates ContinuedThen the insides

were suspended in a fluid filled region and could move around without disturbing each other.Ex. Roundworms

Protostomes and Deuterostomes

During the gastrula phase the hollow ball developed a tube in the middle.

In protostomes, the first opening becomes the mouth (clams, snails, squids, worms, crustaceans, insects, and spiders)

  

Protostomes and Deuterostomes ContinuedIn deuterostomes, the first opening becomes

the anus (sea stars, sea urchins, and vertebrates)

How Classification Began

Classification – grouping of objects or information based on similarities

Taxonomy – branch of biology for grouping and naming organisms

Taxonomists – a biologists who studies taxonomyAristotle

Developed the first method of classificationGrouped them into 2 groups: plants and animalsHis system was useful but did not group

organisms according to their evolutionary history

Classification ContinuedLinnaeus

Developed method we still use todayBased on structural and physical similarities of

organismsBinomial nomenclature - gives each organism 2

names.

The proper way to write a scientific nameExample: animalia, vertebrata, mammalia, primata,

hominidae, Homo sapienAll letters are lower case except the genus is

capitalized. Genus and species are underlined

Animal classification Kingdom LargestPhylum Class Order Family Genus Species Smallest These groups are called taxa.  Kings play chess on flat green stools.

Scientific NamesScientific Names are written in Latin

because:the language is no longer usedthe words stay the same and cannot change

since the language is deadthe words only have one meaningCommon names are misleading because any

organism can have multiple common names

Dichotomous KeyA set of paired statements used to help

identify organismsRead each statement and decide which fits

your organismGo to where that statement tells you and read

the next two statementsEventually you will reach a statement that

tells you the name of the organism

Phylogenetic Classification ModelsSpecies that share a common ancestor also share an

evolutionary historyPhylogeny – the evolutionary history of a species

Phylogenetic classification reveals the evolutionary relationships of species

CladisticsSystem of classification that is based on phylogeny As groups of organisms diverge and evolve from a

common ancestral group, they retain some unique inherited traits.

Cladogram Branching diagram identifying a group’s derived traits. Similar to a pedigree or family tree.Two groups on diverging branches probably share a

more recent ancestor than those groups farther away.

Invertebrates

Phylum: Porifera (sponges)

Classes: 4 Orders: 18 Families: 80Species: about 10,000

No tissues because cells are not specializedNo nerves or muscles, but cells can sense and

react to changes in the environmentOf 10,000 species, 100 of those are in

freshwater

PoriferaSack of cells with poresTop opening is called the

osculum-where water exits out of the sponge

Water goes in through the pores called the spongocoel

Under certain conditions, the cells contract and close all of the openings

Filter feeders

Porifera ReproductionAsexual Reproduction:

BuddingCan regenerate lost partsCan reproduce asexually from a broken piece of the

parent

Sexual ReproductionHermaphrodites (have both male and female parts)

Produces both sperm and egg Sperm shoots out into the water and is then taken

back in (some sponges that are around cross are fertilized)

Phylum:Cnidaria(hydras, jellies, sea anemonies, and coral) Classes:4Orders:27Families: 236Species: 8,000-9,000

Have a single opening that is both the mouth and anus

Sack with one digestive compartment

2 Forms of CnidariansPolyp (hydras and sea

anemones) Tentacles push food

into the mouth Medusa (Jellies)Tentacles have

NEMATOCYSTS – stinging cells that grab and immobilize prey using toxins.

 

Cnidarian ReproductionAsexually – budding (polyp form)Sexually –have separate male and female

medusae that produce gametes that join through external fertilization

Phylum: Platyhelmenthes (Flukes and Tapeworms)Classes: 4Orders: 35Families: 360Species: 17,500

flatwormsSome are microscopic and can grow to be up to 20

m long.Still only have one opening and one digestive cavityAbsorb nutrients across their body surface

 

FlukesLive as parasites in or

on other animals Attach with suckers to

internal organs or to the outer surface

TapewormsAlso Parasites in or on

other animalsHead has suckers and

hooks that lock into intestines

Absorbs food digested by Humans

Absorbs nutrients from digested food

Eggs leave host in the feces

TransmissionThis is why you shouldn’t drink contaminated

water Some cows have the eggs in their musclesWhen we eat under cooked meat, you have a

chance of contracting wormsCan be 20m in length and can block intestines

Flatworm ReproductionSexually - Hermaphrodites – internal

fertilzation.Asexually – fission – when damaged,

regenerates new body parts.

Phylum: Nematoda( pinworms & hook worms)Classes: 4Orders: 25Families: 185Species: 20,000

Humans host about 50 speciesAlso attacks animals and plant rootsOne species is called Trichinella spiralis

causes trichinosis Caused by eating undercooked infected pork or

other infected meat They can go into human muscles or other organs.

Roundworm FeedingHave a simple digestive

system.Have a mouth and an

anusParasitic roundworms

use specialized structures (usually with hooks) to attach to a host.

An Important GroupMany nasty parasitic

infections in humans, livestock

Hookworm

Hookworm

Phylum: Nemertea 1,200 species Probiscis worms or ribbon

worms Can be marine, freshwater, or

live in damp soil Size ranges from .5cm to over

50m Sexual and asexual

reproduction Have a complete digestive

tract & a closed circulatory system. Blood is enclosed in vessels Have no heart, but blood is

propelled by muscles squeezing the vessels

Phylum: AnnelidaClasses: 3Orders: 31Families: 130Species: 12,000Segmented worms (Annelida means “little

rings”) From 1mm to 3 m >

giant Australian earthworm

Class: OligochaetaEarthworm

Divided by septaDigestive tract,

blood vessels, and nerve cords penetrate septa and run the length of the body

Oligochaeta ReproductionHermaphrodites, but they

cross fertilize2 earthworms align and

exchange sperm then they separate

They store the sperm while an organ produces a mucous cocoon.

The cocoon then slides along the worm and picks up the eggs, then the sperm

The cocoon slips off the head and stays in the soil until it hatches

Oligochaeta ReproductionThey can also reproduce

asexually by breaking apart

They eat their way through the soil and absorb nutrients through the soil

Class: Hirudinea Leeches Most live in fresh water, but

some can live in moist vegetation

Some feed on other invertebrates, but some are blood sucking parasites that feed by attaching to the host.

Most abundant in the tropics. From 1-30cm long

• Hermaprodites but can cross fertilize

• Copulation is similar to the earthworm, by making cocoons and buries them in the dirt

FeedingSome use blade like jaws to slit

the skin of the host while others use an enzyme to digest a hole in the skin

Host is usually unaware because the leech secretes an anesthetic

Also secretes an enzyme (hirudin) that keeps the host’s blood from coagulating

It then usually sucks as much blood as it can usually 10X it’s weight can usually last a month without

another meal

Slide 37

Fig. 26.27, p. 440

Human BenefitsWas used by doctors for

blood lettingStill used to treat bruised

tissue and to stimulate blood flow to reattached fingers and toes

Phylum: Mollusca (Snails, slugs, oysters, clams,

octopuses, & squids) Soft bodies but most are

protected by shells All have 3 main body

parts1. Muscular foot

usually used for movement

2. Visceral mass contains most internal

organs3. Mantle

fold of tissue over a visceral mass that secretes a shell

Class: Gastropoda (snails)

Most are either male or female but many snails are hermaphrodites.

Have spiral shells that the animal can retreat into

Some have tentacles on their head w/ eyes at the tips

Move by rippling the foot

Class: Bivalvia (Clams, oysters, mussels, & scallops)Divided shells w/ a hingeMuscle pulls the halves

together to protect the bodyWhen open, the foot comes

out to move the animal or to dig.

Water flows in through an incurrent siphon, passes over the gills then exits through an excurrent siphon

They trap food in the mucous that lines the gills

Secrete threads that attach them to rocks, docks boats, etc.

Class: Cephalopoda (Squids, Octopuses)CarnivoresShell is reduced and

internal in squids and is gone in octopuses

Giant squids can be up to 17m long and can weigh 2 tons

Cephalopods have well developed nervous systems and a complex brain and sensory organs.

Cephalopoda LifeOctopuses live on the

sea floor. They creep and scurry searching for crabs and other food.

They inject poison to immobilize the prey

Mouth is at the center of the tentacles

Squids move by shooting water out of an excurrent siphon (steers by pointing the siphon in different directions)

General CharacteristicsClasses: 6Orders: 36Families: 145Species: 6,000

•Live in marine habitat

•Radial symmetry

•Larval stage has bilateral symmetry

•Body wall bears a number of spines, spicules, or plates made of calcium carbonate•No brain

•Nervous system allows them to respond to information about feed, predators, etc.

Phylum:Echinodermata

•Tube Feet – fluid filled muscular structures that have suckerlike adhesive disks

•Use tube feet for walking, burrowing, clinging to rocks or gripping a meal

•Water-Vascular System

•Unique to echinoderms

•A system of canals delivering water to tube feet

•Each tube foot has an ampulla – a fluid filled muscular structure shaped like a rubber bulb

•As an ampulla contracts, it forces fluid into the foot and causes it to lengthen

•Reproduction

•Sexes separate (few hermaphrodites)

•Large gonads

•No elaborate copulatory apparatus

•Fertilization usually external

Class Asteroidea

•Starfish and sea stars

•Most have a flattened, flexible body with rays (often 5) arranged around a central disc

•The top side (aboral surface) contains the anus and the entrance to the water vascular system called a madreporite

•Sea stars swallow their prey whole

•Get rid of coarse undigested residues through the mouth. Anus is too small to get rid of clam shell

1. Ambulacral Groove

2. Mouth

1. Arm

2. Gonad

3. Stomach

4. Pyloric cecum

Sand Dollars

• Flattened body in endoskeleton plates

• Burrow through sand for food

• Filter feed

• Mouth on oral surface and anus off to one side