Invertebrates

Question 1

What are the four characteristics of animals?

Answer 1

• eukaryotic
• multicellular
• heterotrophs
• no cell wall

Question 2

What are the three types of symmetry in animals?

Answer 2

• asymmetry - no symmetry
• radial symmetry - equal parts surrounding a central cavity
• bilateral symmetry - two equal sides with a head

Question 3

List some facts about invertebrates.

Answer 3

• no backbone
• ectothermic (cold-blooded)
• make up 97% of all living species

Question 4

Define ectothermic.

Answer 4

An organism’s main source of body heat is the external environment

Question 5

What are some characteristics of phyla porifera (sponges)?

Answer 5

• the simplest animals
• no true tissues
• sessile (don’t move around, attached to a substrate)
• can regenerate body parts
• asymmetrical

Question 6

How do sponges eat?

Answer 6

Filter feeders - water enters pores on the body surface, food is trapped inside, and water exits through the top (osculum)

Question 7

What are some characteristics of cnidarians?

Answer 7

• radial symmetry
• tentacles with stinging cells called cnidocytes
• some are free-swimming and some are sessile

Question 8

List some examples of cnidarians.

Answer 8

• jellyfish
• coral
• anemone

Question 9

How do cnidarians capture prey?

Answer 9

Use cnidocytes to paralyze prey, and tentacles to maneuver it into the mouth

Question 10

What is the digestive sac of a cnidarian called?

Answer 10

Gastrovascular cavity

Question 11

What are coral reefs composed of?

Answer 11

Millions of cnidarians; colours come from algae living in symbiosis with the coral

Question 12

What are the three kinds of worm phyla?

Answer 12

• platyhelminites (flatworms)
• nematoda (roundworms)
• amelida (segmented worms)

Question 13

What are some characteristics and examples of flatworms?

Answer 13

• bilateral symmetry
• thin, flat body
• diffusion is used in place of body systems
• 80% are parasitic
• e.g. tapeworm, planarian

Question 14

What are some characteristics and examples of roundworms?

Answer 14

• smooth body with no segments
• complete digestive tract
• found everywhere
• e.g. hookworm, trichinella

Question 15

What are some characteristics and examples of annelida?

Answer 15

• true body cavity called a coelom, which allows them to have more complex organisms
• body composed of segments
• e.g. earthworm, leech

Question 16

How do earthworms contribute to the environment?

Answer 16

Loosen and aerate soil; decompose to create nutrients for other organisms

Question 17

List the three groups of mollusks and some examples.

Answer 17

• gastropods (single shell, e.g. snails)
• bivalves (two shells, e.g. clams, oysters)
• cephalopods (internal or no shell, e.g. squid, octopus)

Question 18

What are two unique body structures of mollusks?

Answer 18

• mantle, which secretes shell
• radula, used to scrape algae off rocks

Question 19

How do mollusks extract oxygen, and what kind of circulatory system do they have?

Answer 19

Gills; open circulatory system

Question 20

What are the three groups of arthropods?

Answer 20

• crustaceans
• arachnids
• uniramians

Question 21

List some characteristics of arthropods.

Answer 21

• jointed limbs
• segmented bodies
• exoskeleton

Question 22

List the primary characteristics of crustaceans.

Answer 22

• body segment called cephalothorax, a fusion of head and thorax
• carapace, a hard calcium carbonate covering over cephalothorax
• two pairs of antennae

Question 23

List some examples of crustaceans.

Answer 23

Crabs, lobster, shrimp, barnacles, isopods

Question 24

What are the primary characteristics of arachnids?

Answer 24

• two body sections: cephalothorax and abdomen
• no antennae
• feeding pincers called chelicerae
• four pairs of legs

Question 25

List some examples of arachnids.

Answer 25

Spiders, scorpions, ticks, mites

Question 26

What organisms are included in the uniramians group?

Answer 26

Insects, millipedes, and centipedes

Question 27

List some characteristics of insects.

Answer 27

- three body segments: head, thorax, and abdomen - three pairs of legs - one pair of antennae - usually one or two pairs of wings

Question 28

State the largest group of insects, and list some characteristics.

Answer 28

Beetles - two pairs of wings, but the front pair is hardened by chitin and shields the back pair

Question 29

Define etymology.

Answer 29

The field of study devoted to classifying and understanding the biology of insects.

Question 30

List some characteristics of the phylum echinodermata.

Answer 30

- spiny skin - no circulatory system - can regenerate body parts - radial symmetry or bisymmetrical

Question 31

List some examples of echinoderms.

Answer 31

- sea urchin - starfish - sea cucumber - sand dollar

Question 32

Describe the water vascular system of starfish.

Answer 32

Branches into tube feet that function for locomotion, feeding, and respiration

Question 33

List the four primary characteristics of phylum chordata.

Answer 33

- notochord: flexible rod through body - dorsal, hollow nerve chord - pharyngeal gill slits - tail

Question 34

What are the two invertebrate kinds of chordates?

Answer 34

- tunicates - lancelets

Question 35

List the nine major invertebrate phyla.

Answer 35

- porifera - cnidaria - platyhelminthes - nematoda - annelida - mollusca - arthropods - echinodermata - chordata