Exam 3 Vocabulary (Ch 32, 33, 34)

Question 1

metamorphosis

Answer 1

A developmental transformation that turns an animal larva into either an adult or an adult like stage that is not yet sexually mature.

Question 2

protostome development

Answer 2

In animals, a developmental mode distinguished by the development of the mouth from the blastopore; often also characterized by spiral cleavage and by the body cavity forming when solid masses of mesoderm split.

Question 3

spiral cleavage

Answer 3

A type of embryonic development in protostomes in which the planes of cell division that transform the zygote into a ball of cells are diagonal to the vertical axis of the embryo. As a result, the cells of each tier sit in the grooves between cells of adjacent tiers.

Question 4

gastrula

Answer 4

An embryonic stage in animal development encompassing the formation of three layers: ectoderm, mesoderm, and endoderm.

Question 5

lophophore

Answer 5

In some lophotrochozo ananimals, including brachiopods, a crown of ciliated tentacles that surround the mouth and function in feeding.

Question 6

blastophore

Answer 6

In a gastrula, the opening of the archenteron that typically develops into the anus in deuterostomes and the mouth in protostomes.

Question 7

body cavity

Answer 7

A fluid- or air-filled space between the digestive tract and the body wall.

Question 8

Lophotrochozoa

Answer 8

One of the three main lineages of bilaterian animals; lophotrochozoans include organisms that have lophophores or trochophore larvae. See also Deuterostomia and Ecdysozoa.

Question 9

diploblastic

Answer 9

Having two germ layers.

Question 10

radial cleavage

Answer 10

A type of embryonic development in deuterostomes in which the planes of cell division that transform the zygote into a ball of cells are either parallel or perpendicular to the vertical axis of the embryo, thereby aligning tiers of cells one above the other.

Question 11

Ecdysozoa

Answer 11

One of the three main lineages of bilaterian animals; many ecdysozoans are molting animals. See also Deuterostomia and Lophotrochozoa.

Question 12

Deuterostomia

Answer 12

One of the three main lineages of bilaterian animals. See also Ecdysozoa and Lophotrochozoa.

Question 13

determinate cleavage

Answer 13

A type of embryonic development in protostomes that rigidly casts the developmental fate of each embryonic cell very early.

Question 14

ectoderm

Answer 14

The outermost of the three primary germ layers in animal embryos; gives rise to the outer covering and, in some phyla, the nervous system, inner ear, and lens of the eye.

Question 15

bilaterian

Answer 15

A member of a clade of animals with bilateral symmetry and three germ layers.

Question 16

Ediacaran biota

Answer 16

An early group of macroscopic, mostly soft bodied, multicellular eukaryotes known from fossils that range in age from 635 million to 541 million years old.

Question 17

cleavage

Answer 17

The succession of rapid cell divisions without significant growth during early embryonic development that converts the zygote to a ball of cells.

Question 18

vertebrate

Answer 18

A chordate animal with vertebrae, the series of bones that make up the backbone

Question 19

archenteron

Answer 19

The endoderm lined cavity, formed during gastrulation, that develops into the digestive tract of an animal

Question 20

tissue

Answer 20

An integrated group of cells with a common structure, function, or both.

Question 21

deuterostome development

Answer 21

In animals, a developmental mode distinguished by the development of the anus from the blastopore; often also characterized by radial cleavage and by the body cavity forming as outpockets of mesodermal tissue.

Question 22

endoderm

Answer 22

The innermost of the three primary germ layers in animal embryos; lines the archenteron and gives rise to the liver, pancreas, lungs, and the lining of the digestive tract in species that have these structures.

Question 23

hemocoel

Answer 23

A body cavity lined by

tissue derived from mesoderm and by tissue derived from endoderm.

Question 24

trochophore larva

Answer 24

Distinctive larval stage observed in some lophotrochozoan animals, including some annelids and molluscs

Question 25

body plan

Answer 25

In multicellular eukaryotes, a set of morphological and developmental traits that are integrated into a functional whole—the living organism.

Question 26

triploblastic

Answer 26

Possessing three germ layers: the endoderm, mesoderm, and ectoderm. All bilaterian animals are triploblastic

Question 27

mesoderm

Answer 27

The middle primary germ layer in a triploblastic animal embryo; develops into the notochord, the lining of the coelom, muscles, skeleton, gonads, kidneys, and most of the circulatory system in species that have these structures.

Question 28

gastrulation

Answer 28

In animal development, a series of cell and tissue movements in which the blastula-stage embryo folds inward, producing a three-layered embryo, the gastrula

Question 29

eumetazoan

Answer 29

A member of a clade of animals with true tissues. All animals except sponges and a few other groups are eumetazoans.

Question 30

blastula

Answer 30

A hollow ball of cells that marks the end of the cleavage stage during early embryonic development in animals

Question 31

coelom

Answer 31

A body cavity lined by tissue derived only from mesoderm.

Question 32

invertebrate

Answer 32

An animal without a backbone. Invertebrates make up 95% of animal species.

Question 33

Cambrian explosion

Answer 33

A relatively brief time in geologic history when many present-day phyla of animals first appeared in the fossil record. This burst of evolutionary change occurred about 535–525 million years ago and saw the emergence of the first large, hardbodied animals.

Question 34

indeterminate cleavage

Answer 34

A type of embryonic development in deuterostomes in which each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo.