Bio Exam 3 - Section 15 (Animals 2)

Annelid

a segmented worm with a true coelom; familiar examples include leeches and earthworms

Arthropod

an invertebrate animal with a cuticle, segmented body, and joined appendages; make up approximately 80% of known species and includes insects, spiders, shrimp, and centipedes

chelicerate

a subphylum of arthropods that includes the spiders and horseshoe crabs; characterized by the front appendages modified into chelicerae

crustacean

a large subphylum of mainly aquatic arthropods (such as crabs and lobsters) that is characterized by appendages that have two branches at the tips

cuticle

the exoskeleton of an arthropod composed mainly of chitin

hydrostatic skeleton

a structure found in many soft-bodied animals (such as worms) consisting of a fluid-filled cavity, the coelom, surrounded by muscles to provide structural support to the animal

invertebrate

an animal with no backbone or spinal column and does not belong to the subphylum vertebrata; most animals are invertebrates

joined appendage

appendages that are jointed and allow for greater mobility

mollusk

invertebrate animals (such as snails, clams, or squids) with a soft unsegmented body usually enclosed in a shell composed mainly of calcium

molting

the shedding of the cuticle to allow for greater growth

nematode

roundworm member of phylum Nematoda; they are psuedocoelomate animals with an unsegmented body and a complete digestive tract

roundworm

common name for nematodes (particularly parasitic nematodes)

segmentation

the division of plant and animals body plans into a series of repetitive segments

Two parts of bilateria

>acoelomates

>coelomates

coelom

fluid lined space (body cavity) that separates the gut from the outer body wall

true coelom

body cavity lined with mesoderm (muscle and tissue)

phylum nematoda

the round worms; many important soil worms and some serious parasitic worms; false coelom, helps make the hydrostatic skeleton

human roundworm

will make its way into you through unclean or uncooked vegetables; it makes its way into your bloodstream and into your lungs

Hookworm life cycle

-it infects 800 M - 1.2 Billion people worldwide

-caused diarrhea, anemia, pneumonia and physical/mental delays

bivalves

soft bodied aquatic animal that has a two part, hinged shell

Evolutionary advantages for cnidarians

>diploblastic

>cnidocysts

>single-opening

diploblastic

oldest living descendants of first “true animals”

cnidocysts

stinging cells in ectoderm for defense

single - opening

serves as both mouth and anus

3 germ layers

>ectoderm

>mesoderm

>endoderm

ectoderm

develops into brain, nervous system, skin

mesoderm

develops into muscles, bones, heart, blood

endoderm

develops into digestive and respiratory systems

Four basic forms for mollusca

1) chitons

2) bivalves

3) gastropods

4) cephalopods 

radula

feeding structure; is like a big tongue covered with teeth

Gastropods (stomach foot)

>snails, slugs, sea slugs, nudibranchs

> largest class, more than half the species

>marine and freshwater

spearfishing attack sequence

1) detection

2) targeting

3) strike

4) capture

Bivalves (2 shells)

>two valved shell, hinged ligament held with adductor muscle

>body laterally flattened

>15,000 extant species, clams, scallops, mussels, and oysters

>lack cephalization

Bivalves

>mostly marine - some freshwater

>cause over 1 billion annually to the US economy

>clog water intakes, foul boat hulls, motors, hurt tourism

cephalopods

>shell divided by septa (mostly lost or greatly reduced)

>closed circulatory system

>foot modified into flexible armsT

The Giant Squid

The largest of the invertebrates; sperm whales eat them, live extremely down deep in the ocean

Class Cephalopoda (head foot)

>all posses a radula, mantle cavity and foot

> head and sensory organs are very well developed

>color change through chromatophore and irrdiocytes

Segmented Worms (Phylum Annelida)

>12,500 species

>vermiform

>soft bodied, circular cross section

Three major groups of segmented worms

>Earth worms

>Polychaeta worms (marine worms)

>Leeches

Leeches

>posterior sucker

>mostly freshwater or terrestrial, not many marine

>most lack setae

segmentation

is the defining feature of annelids - the repetition of anatomically identical units that can be modified for different functions

synapomorphy

a shared derived trait sets one group apart from its ancestors and defines a phylum

Arthropods 3 critical feautures

1) segmented bodies

2) exoskeleton

3) paired, jointed appendages

3 most diverse animal groups

>annelida (segmented worms)

>arthropoda (jointed appendages)

>chordata (includes vertebrates)

Phylum arthropoda Groups

>class arachnids

>class myriapods

>class insects

>class crustacea

subphylum chelicerata

1) absence of antennae

2) body divided into 2 distinct portions (cephalothorax & abdomen) No distinct head

3) first pair of appendages (chelicera) modified for feeding

class arachnida

>spiders, mites, ticks, and scorpions

>2 chelicerae

>2 pedipalps

>4 pair of walking legs

mandibulata

a large group of arthropods that includes insects, crustaceans, and myriapods, all characterized by having mandibles(jaws) for chewing and biting food

order Chilopoda - centipedes

> one leg per segment, some poison

> poison comes from modified leg turned fang

> lack eyes, some have ocelli

class Diplopoda - millipedes

> over 10,000 species - 3 times more than chilopoda

> two pair of legs per segment

> some possess poison glands with a cyanide derivative

class crustacea

> head bears 5 pairs of appendages including two pairs of antennae

> development includes triangular larval form

>about 42,000 species

order stomatopoda

mantis shrimp, large bottom dwelling, violent carnivores with 8 pairs of legs

exoskeletons

serve as protective armor, shielding insects from environmental threats and enabling survival in hostile conditions

class hexaoda (insecta)

>exoskeleton with jointed appendages

>two pairs of flying wings, 3 pairs of legs

Three body segments (Head, Thorax, Abdomen)

Head - sensory reception and food intake

Thorax - movement

Abdomen - reproduction, digestion, and excretion