Invertebrates
By: Sara smith
Some invertebrates are :
sponges
Characteristics of a sponge
* Adult sponges are attached to hard surfaces they can not move.
* Water currents carry food and oxygen to them and take away their waste.
Sponges structure
* Pores- water moves into central cavity of the sponge through pores all over the sponges body.
* Collar cell- whiplike structures that move back and forth to push water through the sponge and traps food.
* Spicules (spikes)- they have no skeleton, but a system of a spikes that keep sponges very hard.
Reproduction
* During asexual reproduction small new sponges grow from the sides of the adult sponge.
* When they fall off they begin their own life.
* Sponges also have sperm and eggs cell, so they can complete sexual reproduction.
These are also some invertebrates.
Cnidarians
Characteristics
* Central body cavity
* Bodies have radial symmetry (symmetrical around a central point.)
The two different types of Body structures.
Polyp
Medusa
Movement
Capturing food
Reproduction
Reproduction asexual
Worms
Characteristics of worm
* All worms have to tissue, origans, and body systems.
* Worms are the simplest organisms with a brain. There brain is a knot of nerve tissue located in its head end, because of this the worm can detect objects, food, mates and predators quickly
Reproduction
* Some worms have members of both genders (male and female).
* Other worms have both male and female sex organs, but usually don't fertilize their own eggs.
* Some reproduce asexually breaking into pieces.
Flat worms
Characteristics of flat worms
* Many flatworms are parasites. Parasites are organisms that live inside another. Others are free living ( not in another organism) in ponds and oceans.
* It takes food in and gets rid of wastes through the same opening.
Round worms
Characteristics of round worms
* They are more advanced than flatworms, with thin round bodies and digestive system that opens at both ends.
* Roundworms live in salt water, fresh water, and the soil (even in Antarctic sands). Many of them are harmful to man as they are parasites.
Segmented worms
Characteristics of segmented worms
* Segmented worms have bodies made up of many linked sections called segmented.
* Segmented worms have nerve tissue and digestive tract that runs the length of the worm's body with a mouth and anus. A closed circulatory system, meaning blood moves within blood vessels. Blood carries oxygen and food to cells.
Examples:
Mollusks
Characteristics all mollusks share.
* Thin layer of tissue called the "foot" is used for movement.
* Bilateral symmetry (same on both sides).
* Mollusks that live under the water have gills.
3 major groups:
Gastropods
Characteristics of Gastropods
* Can have a shell or no shell
* Can be herbivores or carnivores.
* Move by creeping along on a broad foot which can ooze mucus.
Bivalves
Characteristics of bivalves
* Omnivores
* Clams can move! They even dig into the sand.
* Oysters can form a pearl when a grain of sand enters the shell.
Cephalopods
Characteristics of cephalopods
* Carnivores
* Capture prey with their tentacles suckers on the tentacles taste and touch.
* Large eyes for good vision.
* Large brains and can remember things they have learned, some have even escaped captivity!
* Swim by jet propulsion ( current of water).