Bio. II lecture Exam 3

Question 1

Single-cell ancestor

Answer 1

Common, primitive cell from which all life evolved.

Question 2

Multicellular

Answer 2

Organisms composed of multiple specialized cells working together for functions.

Question 3

Porifera

Answer 3

Phylum of aquatic animals, including sponges, with porous body structures.

Question 4

Tissues

Answer 4

Groups of similar cells performing specific functions in multicellular organisms.

Question 5

Cnidarian

Answer 5

Phylum of aquatic animals with stinging cells, including jellyfish and corals.

Question 6

Radial symmetry

Answer 6

Symmetry where body parts radiate from a central point.

Question 7

Bilateral symmetry

Answer 7

A type of symmetry where an organism can be divided into two equal, mirror-image halves.

Question 8

Protostomes

Answer 8

Animals whose mouth develops before the anus during embryonic development.

Question 9

Platyhelminthes

Answer 9

Flatworms, a phylum of soft-bodied, unsegmented invertebrates with simple organ systems.

Question 10

Acoelom

Answer 10

Organism lacking a true body cavity between the gut and body wall.

Question 11

Mollusks

Answer 11

Diverse phylum of invertebrates with soft bodies and often hard shells.

Question 12

Annelids

Answer 12

Phylum of segmented worms with a coelom and bristle-like structures.

Question 13

Segmentation and Coelom

Answer 13

Division of an organism’s body into repeating, similar segments.
Fluid-filled body cavity in some animals, cushions and supports organs.

Question 14

Nematodes

Answer 14

Roundworms, a diverse phylum of unsegmented, cylindrical, and parasitic worms.

Question 15

Pseudocoelom

Answer 15

A body cavity partially lined with mesoderm, found in some animals.

Question 16

Arthropods

Answer 16

Diverse phylum of invertebrates, including insects, spiders, and crustaceans.

Question 17

Deuterostomes

Answer 17

A major group of animals where the anus forms before the mouth during embryonic development.

Question 18

Echinoderms

Answer 18

Marine animals with radial symmetry, like sea stars and sea urchins.

Question 19

Chordates

Answer 19

A phylum including animals with a notochord, such as vertebrates.

Question 20

Parazoa

Answer 20

A subkingdom of animals, including sponges, with primitive body organization.

Question 21

Eumatazoa

Answer 21

A subkingdom of animals with true tissues and more complex organization.

Question 22

Asymmetry

Answer 22

Lack of a specific, balanced arrangement in an organism’s body.

Question 23

Endoderm

Answer 23

Innermost germ layer in an embryo, giving rise to internal organs.

Question 24

Mesoderm

Answer 24

Middle germ layer in an embryo, forming muscles and other tissues.

Question 25

Incomplete digestive tract

Answer 25

A single opening for both ingestion and egestion.

Question 26

Gastrovascular cavity

Answer 26

A digestive chamber with a single opening, found in some animals.

Question 27

Complete digestive tract

Answer 27

Two openings, mouth and anus, for food ingestion and elimination.

Question 28

Segmentation

Answer 28

Division of an organism’s body into repeating, similar segments.

Question 29

Sponges

Answer 29

Simple, aquatic animals with porous bodies, part of the Porifera phylum.

Question 30

Flagellated

Answer 30

Possessing whip-like structures (flagella) for movement or feeding.

Question 31

Mesohyl

Answer 31

Gel-like, acellular matrix in the body of sponges, supporting cells.

Question 32

Spongocoel

Answer 32

Central cavity in a sponge where water enters for filtration.

Question 33

Osculum

Answer 33

Large opening in a sponge through which filtered water exits.

Question 34

Ostia

Answer 34

Small pores in a sponge’s body wall for water intake.

Question 35

Lophocyte

Answer 35

Specialized cells in sponges responsible for generating collagen fibers.

Question 36

Collenocyte

Answer 36

Sponge cells that produce collagen, providing structural support to the organism.

Question 37

Pinacocyte

Answer 37

Flat cells on the outer surface of a sponge’s body.

Question 38

oocyte

Answer 38

Developing egg cell in a female organism.

Question 39

Amoebocyte

Answer 39

Mobile cells in sponges responsible for nutrient transport and more.

Question 40

Sclerocyte

Answer 40

Sponge cells that produce hard, mineralized structures for support.

Question 41

Oscula

Answer 41

The plural form of “osculum,” which are large openings in sponges for water exit.

Question 42

Hermaphroditic

Answer 42

Organism having both male and female reproductive organs.

Question 43

Sperm

Answer 43

Male reproductive cells involved in fertilization.

Question 44

Eggs

Answer 44

Female reproductive cells, typically larger and non-motile, involved in fertilization.

Question 45

Cnidarians

Answer 45

Phylum of aquatic animals with specialized stinging cells (cnidocytes).

Question 46

Medusa

Answer 46

A free-swimming, umbrella-shaped form of some cnidarians, like jellyfish.

Question 47

Polyp

Answer 47

A sessile, tube-shaped form of some cnidarians, like coral colonies.

Question 48

Nematocyst

Answer 48

Specialized stinging organelles found in cnidarians, used for defense and capturing prey.

Question 49

Hydras

Answer 49

Tiny, freshwater cnidarians with simple body structures, often resembling polyps.

Question 50

Parasitic

Answer 50

Organism that lives off another, often harming its host in the process.