Chapter 30

Question 1

What are the key traits of animals?

Answer 1

Animals are multicellular eukaryotes with no cell walls but with an extensive extracellular matrix.

Question 2

What is the monophyletic group of animals?

Answer 2

All animals have a single common ancestor that was multicellular.

Question 3

What is the prevailing hypothesis about the lineage of animals?

Answer 3

Sponges are considered the most ancient lineage of animals.

Question 4

What characteristics do sponges share with choanoflagellates?

Answer 4

Sponges share certain cellular characteristics with choanoflagellates.

Question 5

What defines animals in terms of nutrition and movement?

Answer 5

Animals are multicellular, heterotrophic eukaryotes that ingest their prey and move under their own power at some point in their life cycle.

Question 6

What are diploblastic animals?

Answer 6

Diploblastic animals have embryos with two types of tissues or germ layers: ectoderm and endoderm.

Question 7

What are triploblastic animals?

Answer 7

Triploblastic animals have embryos with three germ layers: ectoderm, endoderm, and mesoderm.

Question 8

What does the ectoderm develop into?

Answer 8

The ectoderm develops into skin and nerves.

Question 9

What does the mesoderm develop into?

Answer 9

The mesoderm develops into muscles, internal organs, bones, and circulation.

Question 10

What does the endoderm develop into?

Answer 10

The endoderm develops into the respiratory and digestive tract.

Question 11

What type of symmetry do some sponges have?

Answer 11

Some sponges have radial symmetry, with at least two planes of symmetry.

Question 12

What is bilateral symmetry?

Answer 12

Bilateral symmetry is characterized by a single plane of symmetry and long, narrow bodies.

Question 13

What is a coelom?

Answer 13

A coelom is an enclosed, fluid-filled body cavity between the tubes that allows for the circulation of oxygen and nutrients.

Question 14

What are coelomates?

Answer 14

Coelomates have an enclosed coelom completely lined with mesoderm-derived tissue.

Question 15

What are acoelomates?

Answer 15

Acoelomates, or ‘no-cavity-form’, have no enclosed coelom, such as flatworms.

Question 16

What are pseudocoelomates?

Answer 16

Pseudocoelomates, or ‘false-cavity-form’, have a coelom that is only partially lined with mesoderm, such as roundworms and rotifers.

Question 17

What are protostomes?

Answer 17

Protostomes are animals where the mouth develops before the anus during embryonic development.

Question 18

What are deuterostomes?

Answer 18

Deuterostomes are animals where the anus develops before the mouth during embryonic development.

Question 19

What are detritivores?

Answer 19

Detritivores feed on dead organic matter, such as decaying leaves.

Question 20

What are herbivores?

Answer 20

Herbivores feed on plants or algae, such as bamboo.

Question 21

What are carnivores?

Answer 21

Carnivores feed on animals, consuming their prey.

Question 22

What are omnivores?

Answer 22

Omnivores feed on a combination of plants, animals, fungi, protists, archaea, and/or bacteria, such as humans.

Question 23

What are endoparasites?

Answer 23

Endoparasites live inside their host and usually have simple, wormlike structures.

Question 24

What are ectoparasites?

Answer 24

Ectoparasites live outside their host and usually have limbs or mouthparts that allow them to grasp the host.

Question 25

What are suspension feeders?

Answer 25

Suspension feeders capture food by filtering out particles floating in water or drifting through the air, like barnacles.

Question 26

What are deposit feeders?

Answer 26

Deposit feeders ingest organic materials that have been deposited within a substrate or on its surface, like sea cucumbers.

Question 27

What are fluid feeders?

Answer 27

Fluid feeders suck or mop up liquids like nectar, plant sap, blood, or fruit juice, such as butterflies and moths.

Question 28

What are mass feeders?

Answer 28

Mass feeders take chunks of food into their mouths, like lions biting off chunks of meat from their prey's carcass.

Question 29

What is the stimulus for sight?

Answer 29

The stimulus for sight is light.

Question 30

What is the stimulus for hearing?

Answer 30

The stimulus for hearing is sound.

Question 31

What is the stimulus for taste and smell?

Answer 31

The stimulus for taste and smell is molecules.

Question 32

What is the stimulus for touch?

Answer 32

The stimulus for touch is pressure or contact.

Question 33

What are the three types of skeletal systems that enable complex movements?

Answer 33

1. Hydrostatic skeleton 2. Endoskeletons 3. Exoskeletons

Question 34

What is a hydrostatic skeleton?

Answer 34

Support from a flexible body wall in tension surrounding fluid or soft tissue under compression. | Ex. Starfish ## Footnote A hydrostatic skeleton is a skeleton made of fluid-filled muscles (ceolom) instead of bones

Question 35

What is an endoskeleton?

Answer 35

Support derived from rigid structures inside the body, such as bone in vertebrates and spicules in sponges. ## Footnote Example: Human bone structure

Question 36

What is an exoskeleton?

Answer 36

Support derived from rigid structures on the outside of the body, such as the external armor of arthropods. ## Footnote Example: Seceda - Shred their skin

Question 37

What is asexual reproduction?

Answer 37

Genetically identical clones produced by fission (splitting) or budding.

Question 38

What is sexual reproduction (external fertilization)?

Answer 38

Corals reproduce sexually by releasing eggs and sperm into open water, where fertilization occurs.

Question 39

What is internal fertilization?

Answer 39

Fertilization that occurs inside the body.

Question 40

What does viviparous mean?

Answer 40

Species that nourish embryos internally and give birth to living young. ## Footnote Example: Most mammals - Human birth

Question 41

What does oviparous mean?

Answer 41

Species that deposit fertilized eggs; embryos are nourished by yolk. ## Footnote Example: Most insects, birds

Question 42

What does ovoviviparous mean?

Answer 42

Species that retain eggs internally (embryos are nourished by yolk) and give birth to live young. ## Footnote Example: Guppies, garter snakes

Question 43

What was the Cambrian Explosion?

Answer 43

About 541 million years ago to about 530 million years ago, most major animal phyla (and hence most body plans) appeared for the first time.

Question 44

What is metamorphosis?

Answer 44

A drastic change from one developmental stage to another.