Biology Lab Final

Chordates, echinoderms, arthropods, annelids, mollusks, and platyhelminths

Cnidarians

Poriferans

Chordates, echinoderms, arthropods, annelids, and mollusks

Chordates and echinoderms

Arthropods, annelids, and mollusks

• The central cavity of sponges
• Facilitates water circulation (not a digestive chamber because no digestive enzymes are released into cavity)

• The excurrent opening of sponges.
• Where water leaves the songe

a primitive form of the structural support of sponges

• Stinging cells that all cnidarians have
• Used for protection and for catching food

Stinging devices on the surface of the tentacles that cnidarians discharge when they brush against a potential prey item or predator

• Medusa
• They contain gonads which are clusters of gametes (eggs and sperm)

They can reproduce both asexually (like polyps by "budding") and sexually (with eggs and sperm, like the medusa form)

Bilateral symmetry, three distinct body layers and true organ systems: sensory, nervous, excretory, and reproductive systems

• The differentiation and specialization of the anterior end of the body (in the head)
• Flatworms

Bilateral symmetry allows the animal to have directed movement which can help when searching for food or escaping predators. It also allows for quicker and precise response to stimulation since the nervous system is cephalized and much more complex.

Through a pharynx, an extendible, muscular tube on the ventral side of the animal

• The gastrovascular cavity is for digestion and internal transport, the spongocoel facilitates water circulation.
• The spongocoel is bigger than the gastrovascular cavity.

Platyhelminths

• A muscular head-foot which is a visceral mass
• A fleshy mantle that secretes
• A protective (internal or external) shell

• Surface-feeding gastropods (snails)
• Filter-feeding bivalves (clams)
• Free-swimming, predatory cephalopods (squids)

• A dorsal fold of tissue that secretes the shell
• In clams and snails, the shell is external; in squid and octopus, the shell is reduced and internalized

• Contains the gills
• Water drawn into the mantle cavity is used for gas exchange
• In squid, water forced out of the mantle cavity can be used for jet propulsion

Two large muscles attached to the shell and used to pull the valves tightly closed in clams

It has evolved into a separate head and several, sucker-covered tentacles

• Clams extensions of the edge of the mantle
• Water passes into the mantle cavity through the ventral, incurrent siphon and out through the dorsal, excurrent siphon

• The body is composed of repeated similar segments or "metameres"
• This condition is known as metamerism and is also found in arthropods and chordates

• A "second" body cavity that surrounds and is completely separate from the digestive cavity
• Inside this fluid-filled space the internal organs:
• a. increase their surface are by bending and coiling (human intestine)
• b. can fill, empty, and slide past one another, lubricated with coelomic fluid (human lungs)

Setae are bristles on earthworms that attach to surfaces and prevent backsliding during persisteltic motion

Pairs of fleshy projections along the side of the clamworms body

Parapodia have a large surface area and keep fresh water with a high oxygen concentration constantly moving over the respiratory surface.

The contraction of the parapodia allow it to move

Arthropods

Joint-footed

An exoskeleton and jointed appendages

• head, thorax, and abdomen
• In crustaceans and arachnids, the head and thorax are fused into a cephalothorax

The abdomen

• Insects have 3
• Crustaceans and arachnids have 4
• The thorax or cephalothorax

Insects and crustaceans

Insects have one and crustaceans have two

In arachnids, the first pair of appendages that has been modified into fang-like mouth parts

• In spiders, the second pair of ancestral appendages
• For manipulating food and, in males, for transferring sperm to the female

Insects

• Exploit widely dispersed food sources
• Escape from predators
• Disperse into new habitats

• Larger, with multiple facets/lenses
• Compound eyes form images and are especially well adapted for detecting motion

first mouth

second mouth

• Unique to Echinoderms
• The tube feet of the starfish are part of this
• hydraulic, water fills the tube feet making them rigid enougth to all the starfish to walk

Protrusions of the coelom that serve as sites of gas exchange on starfish

• A dorsal, hollow nerve cord
• A notochord (a stiff rod running under the nerve cord)
• Pharyngeal ("throat") gill slits
• Tail

• The fishes (lamprey eels, cartilaginous fishes (sharks) and bony fishes
• The tetrapods (four foot) amphibians, reptiles, birds, and mammals

• Invertebrates (no backbone)
• Dorsal, hollow nerve cord; pharyngeal gill slits; tail

Sponges

Jellyfish, hydra

Flatworms

• Gastropods (snails, slugs)
• Bivalves (clams, oysters)
• Cephalopods (octopus, squid)

Segmented worms

• Arachnids (spiders)
• Crustaceans (crabs, lobsters)
• Insects

• Starfish
• "spiny skinned"

• Invertebrates (tunicates)
• Vertebrates (sharks, bony fish, amphibians, reptiles, birds, and mammals)

Cnidarias and Platyhelminths

Diploid spore mother cell to haploid spores

Haploid gametes (egg and sperm) to diploid zygote

The division of the nucleus

In spore mother cells

BryophytesThey lack vascular tissues; have on true stems

Seedless, vascular

Flagellated sperm that need to swim through surface water to reach the egg in the female gametangia

large, leathery leaves ferns are known for having

the reduced, underground creeping stems that roots grow off of in ferns

clusters of (spore producing) sporangia on the underside of the fronds of ferns

The sporangia, fronds, roots and rhizomes

Vascular plants with "naked" seeds (conifers: cone-bearing plants)

Seeds that are not protected inside a fruit

reproduction except that the reproductive structures are housed inside cones instead of inside flowers

In the male cones where microspores are produced which develop into small male gametophytes (pollen grains)

The female gametophyes, which have been reduced to small clusters of cells that develop into seeds when fertilized by pollen

• One or more gametangia, each containing an egg cell
• A mass of haploid tissues from the female gametophyte

In conifers, regular meiosis takes the pollen grains into the ovule fertilizing and producting a seed. In ferns, it is carried through the anteridium to the archegenium where fertilization takes place

Flowering plants

In the flowers, where sexual reproduction occurs, in which seeds are formed, and from which fruits develop.

Inside the anther of a flower

With the specialized cells called microspore mother cells

Inside the ovules of the flowers ovary

With the specialized cells called megaspore mother cells

• It is in angiosperms
• It involves two fertilization events, the first triggers development of the embryo and the second provides nutrition for the embryo

• Pollination is when pollen is transferred in plants, enables sexual reproduction
• Fertilization is the fusion of gametes to produce a new organism

The ripened ovary wall

• When plants reproduce asexually
• This only requires one parent to produce new plants
• All the offspring are genetically identical to the parent plant, because only mitosis is involved, not meiosis