Overview of Animal Diversity

Question 1

Animals

Answer 1

Multicellular, heterotrophic eukaryotes that feed by ingesting their food.

Question 2

Diploid

Answer 2

Most animals are diploid, and produce gametes produced directly by meiosis.

Question 3

Extracellular matrix

Answer 3

Support structure used by animals instead of cell walls.

Question 4

Motile

Answer 4

Exhibiting active movement at some point in their life.

Question 5

Sexual reproduction

Answer 5

Most animals reproduce sexually, although some reproduce asexually.

Question 6

Embryonic development

Answer 6

Process where a zygote undergoes cleavage.

Question 7

Viviparous

Answer 7

Embryo nourished inside parent, giving birth to live offspring.

Question 8

Oviparous

Answer 8

Parent lays egg, embryo is nourished by yolk in egg.

Question 9

Ovoviviparous

Answer 9

Eggs remain inside parent until ready to hatch, embryo is nourished by yolk.

Question 10

Homeobox genes

Answer 10

Genes common to almost all animals that control the development of the body.

Question 11

Tissues

Answer 11

Organized groups of similar cells that act as a functional unit.

Question 12

Nervous system

Answer 12

Coordinates actions and transmits signals around the body of animals (except sponges).

Question 13

Cleavage

Answer 13

Rapid mitotic cell divisions in the zygote.

Question 14

Blastula

Answer 14

Hollow ball of cells (mammalian blastula is called blastocyst).

Question 15

Gastrulation

Answer 15

Formation of the three germ layers, forming a gastrula.

Question 16

Blastopore

Answer 16

The opening that forms to the digestive tube (archenteron).

Question 17

Ectoderm

Answer 17

Cells that remain outside and form nerves, adrenal medulla, skin, brain, eyes, and inner ear.

Question 18

Mesoderm

Answer 18

Internal cells that give rise to organs, adrenal cortex, blood, bone, gonads, and the soft tissues.

Question 19

Endoderm

Answer 19

Innermost cells that form the epithelial linings of the digestive tract, liver, pancreas, and lungs.

Question 20

Protostomes

Answer 20

Blastopore develops into mouth, and mesoderm hollows out to form coelom.

Question 21

Deuterostomes

Answer 21

Blastopore develops into anus, and mesoderm pinches off pockets from archenteron that form coelom.

Question 22

Spiral cleavage

Answer 22

Plane of cell division is diagonal to the vertical axis of the embryo.

Question 23

Radial cleavage

Answer 23

Plane of cell division is parallel or perpendicular to the vertical axis of the embryo.

Question 24

Indeterminate cleavage

Answer 24

The cells that arise are able to develop into a whole organism.

Question 25

Determinate cleavage

Answer 25

The cells that arise are committed to differentiation.

Question 26

Diploblast

Answer 26

Two primary germ layers of the blastula, ectoderm and endoderm.

Question 27

Triploblast

Answer 27

Three primary germ layers of the blastula.

Question 28

Coelom

Answer 28

Body cavity inside an animal that surrounds the digestive tract, and is derived from the mesoderm.

Question 29

Pseudocoelom

Answer 29

Body cavity that surrounds the digestive tract, and is derived from the mesoderm and endoderm.

Question 30

Coelomates

Answer 30

Triploblasts that have a true coelom.

Question 31

Pseudocoelomates

Answer 31

Triploblasts that have a pseudocoelom.

Question 32

Acoelomates

Answer 32

Triploblasts that lack a coelom.

Question 33

Radial symmetry

Answer 33

Arrangement of body parts around one main axis.

Question 34

Bilateral symmetry

Answer 34

Organism body plan is divided into two roughly equal halves.

Question 35

Body axes

Answer 35

Anterior - toward the head, Posterior - toward the tail, Dorsal - toward the back, Ventral - toward the belly.

Question 36

Neurulation

Answer 36

Formation of nervous tissue from primary germ layers.

Question 37

Notochord

Answer 37

Primitive backbone formed in chordates during development.

Question 38

Neural tube

Answer 38

Hollow structure that the brain and spinal chord derive from.

Question 39

Cephalization

Answer 39

Evolutionary trend in which nervous tissue becomes concentrated toward the anterior end of an organism.

Question 40

Brain

Answer 40

Mass of neurons in the head that integrates and processes sensory information.

Question 41

Central nervous system

Answer 41

Neurons are clustered into one or more large tracts that project through the body.

Question 42

Nerve net

Answer 42

Diffuse arrangement of nerve cells found in radially symmetric animals.

Question 43

Segmentation

Answer 43

The presence of repeated body structures.

Question 44

Vertebrates

Answer 44

Have a vertebral column developed from the notochord, most are deuterostomes.

Question 45

Invertebrates

Answer 45

Lack vertebral column developed from the notochord, still have segmented bodies, most are protostomes.