higher invertebrates

simple lower invertebrates

porifera, platyhelminthes, nematoda, cnidaria

higher invertebrates

annelida, mollusca, anthropoda, echinodermata, chordata

definitions of lower

-porifera-sponges

-platyhelminthes-flatworms

-nematoda-roundworms

-cnidaria-jellyfish,sea anemones, and corals

definitions of higher

annelida-segmented worms

mollusca-clams, squid, snails

anthropoda-crustaceans,spiders,insects

echinodermata-sea urchins, sea cucumbers, sea stars

chrodata-all vertebrates

annelida background

-540 million years ago

-segmented worms: earthworms, bristle worms, leeches

annelida characteristics

-bilateral symmetry

-cephalized

-ectotherms

-invertebrates

-coelomates

-closed circulatory system

closed circulatory system

blood is enclosed in vessels

open circulatory system

hemolymph is enclosed in vessels

annelida eyes and gills

some have eye spots, others more complex eyes

terrestrial annelida rely on diffusion for gas exchange, other with gills

annelida first to develop?

gills [for gas exchange], circulatory system,

annelida segments

-organs repeated each segment

-segments can regrow if needed

-segments can be specialized for specific functions

-segments=efficient movement, they also use appendages to help

annelida meaning

little rings

higher invertebrates are considered higher because?

they all have a true coelom

organs

organs are well organized and lined with tissue and muscle

digestive system

complete like nematodes, dispose of waste through anus, have jaws at mouth

what do oligochaetes do?

they dig- helps with plant growth

they decompose nutrients

annelida reproduction

asexual - budding

and sexual - hermaphroditic

all 3 worm phyla are?

ectothermic invertebrates with cephalization and bilateral symmetry

Mollusca background

530 million years ago

3 classes: bivalves, gastropods, cephlapods

ex: snails, slugs, octopuses, clams, oysters, squids

mollusca characterisitcs

invertebrates, ectotherms, bilateral symmetry, coelomates, cephalization [except bivalves]

gastropods

slugs and snails

stomach foot

secrete mucus to help with movement

many have single shell adapted to land and eyes

bivalves

clams and other two-shelled shellfish

two doors

filter feeders

gills

hard shell

cephalapods

squids and octupi

head foot

agile swimmers

complex nervous system with eye

no shell

well developed head

mollusca respiration

gills for gas exchange

mollusca circulation

bivalves and gastrohave open, while cephalopods closed

mollusca respiration

gastro and cephalopods have internal diffusion

mollusca cephalization

gastro and cephalopods yes

bivalves no

gastro nervous system

Gastropods - have centralized nervous systems with network of cerebral ganglia, have eyes, can sense, smell, touch and taste.

bivalves nervous system

Bivalves- Relatively simple nervous systems, no brain, but does have ganglion. can sense touch, light and taste.

cephalopods nervous system

Cephalopods - most advanced nervous system of all mollusks, they have large brains that have been known to help with problem solving, have well developed eyes and other sense organs.

foot

broad muscular structure for movement

visceral mass

contains gills, gut, and other organs inside coelom

mantle

covers visceral mass protects in species without shell

shell

protects and keeps land species from drying out

mollusca heterotrophy

-can be predators or filter feeders

radula

tongue like structure with tiny teeth to help gastro and cephalopods with feeding

some mollusks use it to scrape out other mollusca shells

Arthropoda background

-530 million years ago

- largest of the phyla of animals

-5 types: arachnids, crustaceans, insects, millipedes, centipedes

arthropoda characteristics

- ectotherms

-bilateral symmetry

-cephalized

-coelomates

-invertebrates

insects

ants, bees, bettle, etc

crustaceans

crabs, lobsters, shrimps

arachnids

spiders, scorpions, ticks

centi/millipedes

arthropods with many legs

arthropod nervous system

all are cephalized

similar to annelida system

ganglia concentrated in head with other sense organs

brain connected to a series of nerves through segments of body

compound eyes

effective eyes at detecting and tracking motion

arthropod respiration

marine use gills

insects use tracheal tubes for diffusion

book lungs

folded stacks of tissue exchange o2 and co2

arthropods circulation

all have open circulatory system

hemolymph

blood like fluid in invertebrates

arthropod meaning

jointed feet

arthropods nervous system similar to what? what does this mean?

similar to annelids, suggest past annelid ancestry

arthropod exoskeleton made of what? what is the use?

chitin and protein

provides protection and helps terrestrial arthropods retain water

molting

the growing of the body and the shedding of the exoskeleton

metamorphosis

the transformation from immature form to adult form

incomplete metamorphosis

young that hatch from eggs that look like adult form

complete metamorphosis

appearance changes completely throughout four stages:

egg, larva, pupa, adult

molting occurs to whom?

arthropods, amphibians, reptiles, and birds

metamorphosis occurs to whom?

cnidarians, crustaceans, mollusks, insects, fish, amphibians, echinoderms, and all chordata

echinodermata background

-530 million years ago

-ex: sea urchins, sea cucumbers, sea stars, and sand dollars

echinodermata characteristics

-ectotherms

-invertebrates

-coelomates

-radial symmetry as adults

-bilateral symmetry as larva

-open circulatory system

echinodermata cephalized or not?

no

echinodermata nervous system

-simple nervous system, nerves radiate from nerve ring around mouth

-some gangliation found

-some starfish have eye spots that can detect light intensity

echinodermata sexual reproduction

release male sex cells into water

echinodermata asexual reproduction

split and regenerating body parts for asexual reproduction

endoskeleton

mineralized, hard plates that are covered by skin
usually covered with spiny projections

water vascular system

hydraulic system used to help echinoderms eat, move, and obtain oxygen

muscles contract, drawing water into tube feet to circulate through body

tube feet

small tubular projections that produce movement via pressure induced by water vascular system