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