chapter 25-27 by: stacy mckinney andrew strawther mikayla brown jared rudd

Chapter 25-27By: Stacy Mckinney

Andrew Strawther

Mikayla Brown

Jared Rudd

Chapter 25 Animals

Animals are eukaryotic, multicellular, heterotrophic organisms.

The first animals evolved in water.Digestion for animals takes place in a

internal cavity.Animals have special cells that help it

seek out food and mates, it also allows them to protect themselves from predators.

Chapter 25 Animals

The process of a baby forming inside a animal is the same inside of a human.

Chapter 26 Section 1&2

Sponges are very simple animals that live permanently attached to a location in the water , they are sessile as adults.

Most sponges are hermaphrodites (an be male or female) fertilization is external sponges release sperm that floats till it finds another sponge. Sponges can break off and attach to rocks and grow as a clone of the first sponge.

Chapter 26 Section 2 Cnidarians are a diverse group of aquatic

animals, more than 9000 species are part of the phylum cnidarian, and all species are aquatic , cnidarians are widespread in marine habitats and less common in fresh water.

Cnidarians come in two forms polyp, medusa.

Polyps- stationary sponges for life

Medusa-freemoving , true jelly fish are meduas.

Classes of cnidarians

AnthozoaScxphozaHydrozoacubozoa

Unsegmented Worms

CHAPTER 26, section 3 and 4

FLATWORMS

Belongs to the phylum (plat=flat)

3 classes:

-turbellaria

-trematoda

-cestoda

CHARACTERISTICS

Acoelomates – (no body cavities) They have bilateral symmetry Respiration through skin

Class Turbellaria

spade shaped head and 2 eyespotsScavengersFlame cells remove wasteHermaphrodites (have male and

female parts) Reproduce by regeneration

Class Trematoda

Parasitic flukes Have suckers on both ends of the

bodyCan live inside or outside of hostHermaphrodites Have complex life cycles

LIFE CYCLES

EggMiracidium(free living in water)Sporocyst (in snail)Redia (in snail) Cercaria (free living in water/snail)Metacercaria (in second intermediate

host) adult

Class Cestoda

ParasiticTapewormsLong bodiesAbsorbs nutrients from hosthermaphrodites

ROUNDWORMS

Roundworms

belong to phylum NematodaSlender bodies that taper on both

ends Have mouth and anusCan be free living or parasitic

Pinworms live in human intestines

Trichinosis is a disease from eating infected pork

Rotifers

known as wheel animalsFree swimming, transparentFreshwater and marineHave a ring of cilia around mouth that

brings in foodFeed on unicellular algae and bacteriaHave a muscular organ that chops food

Chapter 27

What is a mollusk?

-slugs, snails, squids, and some animals that live in shells in the ocean or on the beachMollusks have bilateral symmetry, a

coelom, a digestive tract with two openings, a muscular foot, and a mantle

Chapter 27

Mollusks use a rasping structure called radula to obtain food

-radula can be used to drill, scrape, grate, or cut out foodThey reproduce sexually

Chapter 27

Have simple nervous systems that control their movement and behavior

Have well-developed circulatory system that usually includes a two or three-chambered heart

Chapter 27

Most mollusks have an open circulatory system; the blood moves through vessels and into open spaces around the body organs

Some move nutrients and oxygen through a closed circulatory system; blood moves through the body enclosed entirely in a series of blood vessels

Most have respiratory structures called gills

Chapter 27

Three classes

-Gastropoda; one-shelled

-Bivalvia; two-shelled

-Cephalopoda; head-footed

Chapter 27

What is a segmented worm?

-leeches, bristleworms, earth wormsBilaterally symmetrical and have

coelom and two body openings

Chapter 27

Food is taken in by the mouthHave simple nervous systems,

organs have become modified for sensing the environment

Have closed circulatory systems

Chapter 27

Earthworms and leeches are hermaphnodites

Bristleworms reproduce sexually

Chapter 27

Three classes

-Oligochaeta; earthworms

-Polychaeta; brislteworms

-Hirudinea; leeches