Chapter 28: Invertebrate Diversity

Question 1

Protosome

Answer 1

multicellular organism whose mouth develops from a primary embryonic opening
Ex. An annelid, mollusk, nematode or arthropod.

Question 2

Deuterostome

Answer 2

Organisms whose anus forms before their mouths in embryonic development
Ex. Echinodermata

Question 3

Sessile

Answer 3

Sponge anchored in one place, cannot escape predators in this stage

Question 4

Radial symmetry

Answer 4

Organism whose body parts radiate from a central body

Cnidarian characteristic

Question 5

Coelum

Answer 5

internal body cavity space between digestive structures and body wall
Platyhelminthes or Cnidarians don’t have this
Mollusks, Echinodermata and Annelida do have this

Question 6

Cynidocytes

Answer 6

In Cnidarians
Explosive cell on tentacles that could sting predators if needed
Have structures called nematocysts inside them

Question 7

Nematocysts

Answer 7

A specialized cell in Cnidarians

Acts as defense and to capture food

Question 8

Spicules

Answer 8

Sponges chemical form of defense

Question 9

Bilateral symmetry

Answer 9

If split a body in half, the parts are the same on both sides
Flatworms have this characteristic

Question 10

Dioecious

Answer 10

Male and female reproductive organs are in separate organisms

Question 11

Hermaphrodite

Answer 11

An organism having both male & female parts in one organism

Question 12

Metamerism

Answer 12

True segmentation

Segmented worms

Question 13

Setae/chaetae

Answer 13

thin external cuticle, projecting hairlike extensions

On annelida

Question 14

Spiracles

Answer 14

Characteristic of Arthropoda

Little holes where gas exchange can occur

Question 15

Book lungs

Answer 15

Part of Arthropoda

Question 16

Book gills

Answer 16

Part of Arthropoda

Question 17

Pentaradial

Answer 17

part of Echinodermata

5 segments outstretched from inner circle

Question 18

Hexipoda

Answer 18

Part of Arthropoda 
6 pairs of legs
3 body segments
can be winged or not,
usually have antenna attached to the head, abdomen contains reproductive structures.

Question 19

Myripoda

Answer 19

Part of Arthropoda
Many legs
usually found in dead decaying matter in soil

Question 20

Sponges

Answer 20

Do not have tissues, do have specialized cells.
Have free-swimming larval stage; sessile adult stage
No nerves or muscles, but individual cells can sense and react to changes in the environment.
Both marine AND freshwater species

Question 21

Cnidarians

Answer 21

Radial Symmetry
Arise from two layers of tissue
No internal organs or coelom
Both marine and freshwater species
Contain stinging cells on tentacles called cynidocytes. Cynidocytes have structures
called nematocysts.

Question 22

Cnidarian Life Cycle

Answer 22

Sexual Reproduction
Medusa and polyp stages

Asexual reproduction
Always a polyp
All generations are identical

Question 23

Platyhelminthes (flat worms) characteristics

Answer 23

Bilateral Symmetry
Some level of cephalization, anterior eye spots (detect light), chemoreceptors, simple brain.
Follows protostome development, but lacks coelom
Many are non-self fertilizing hermaphrodites
Marine, freshwater, and terrestrial species

Question 24

Platyhelminthes Life Cycle

Answer 24

Some are parasitic so develop from eggs to larvae inside humans

Question 25

Nematodes characteristics

Answer 25

Also known as roundworms
Lack segmentation
Most are very small (less than 2.5 mm), but can go up to 5cm; species are freshwater, marine, terrestrial – many parasitic
Follow protostome development, but have a pseudocoelom filled with acellular fluid.
Some are hermaphroditic, some can self fertilize, some are dioecious (male/female)
External layer is a cuticle with collagen.

Question 26

Mollusks characteristics

Answer 26

Contain a muscular foot, visceral mass with internal organs, and mantle - some have shell formation that can be internal (i.e. squid) or external (i.e. snail)
Three general classes: Bivalves, Gastropoda, Cephalopoda
Marine, freshwater, terrestrial
Protostome development, but are coelomates (have true coelom)
Some are hermaphroditic (most non-self fertilizing), but most are dioecious

Question 27

Annelida

Answer 27

Segmented worms – metamerism (true segementation)
Found in marine, freshwater, terrestrial habitats
Protosomic development with coelom
Have thin external cuticle, projecting hairlike extensions called setae/chaetae
Developed/complete digestive system
Some can asexually reproduce through budding, but most are either non-self fertilizing hermaphrodites or dioecious

Question 28

Arthropoda characteristics

Answer 28

Body segments
Jointed appendages
Respiration can vary some have spiracles gas exchange occurs directly between the cells and air in tracheae, gills (crusteans), book lungs, book gills.
Some are hermaphrodites, but most are dioecious
Freshwater, marine, and terrestrial

Question 29

Arthropoda subphylum’s

Answer 29

Hexipoda
Myripoda
Crustacea
Chelicerata

Question 30

Hexipoda

Answer 30

6 pairs of legs
3 body segments
can be winged or not
usually have antenna attached to the head, abdomen contains reproductive structures
Ex. Bees

Question 31

Myripoda

Answer 31

Many legs, usually found in dead decaying matter in soil

Ex. Centipede

Question 32

Crustacea

Answer 32

Most are aquatic, but some terrestrial
have 2 body segments (head/thorax fused to produce a cephalothorax)
breathe by use of gills
Ex. Beetle?

Question 33

Chelicerata

Answer 33

2 body parts
have chelicerae
don’t have antennae
have pedipalps
can have either gills or book lungs
Ex. Scorpions

Question 34

Chelicerae

Answer 34

specialized, claw-life or fang appendages

Question 35

Pedipalps

Answer 35

a second pair of appendages, usually on front part of head

Question 36

Echinodermata

Answer 36

Spiny skin, pentaradial symmetry in adult form, bilateral symmetry in larval stages
ONLY phylum of animal that is strictly marine
Endoskeleton made of ossicles (bone-like)
Many have tube feet for mobility; water vascular system
Deuterosomes with a true coelom
Regeneration happens
Reproduction is usually sexual – some are hermaphroditic, some dioecious