Ch 33: Animal Form, Function, and Evolutionary History

Question 1

Porifera

Answer 1

Sponges; a phylum characterized by an irregular form with no clearly defined plane of symmetry

Question 2

Cnidaria

Answer 2

A phylum characterized by radial symmetry, two germ tissues in the embryo, a closed internal gastric cavity, and well developed tissues but not organs; included jellyfish, sea anemones, and corals

Question 3

Bilateria

Answer 3

The monophyletic group of animals with bilateral symmetry

Question 4

Cephalization

Answer 4

The concentration of nervous system components at one end of the body

Question 5

Segmentation

Answer 5

The formation of discrete repeating parts or segments in the developing body of many animal embryos.

Question 6

Dipoblasitc

Answer 6

Describes animals in which the embryo has two germ layers, the endoderm and the ectoderm, from which the adult tissues develop.

Question 7

Tripoblastic

Answer 7

Describes animals in which the embryo has three germ layers, with the mesoderm between the endoderm and ectoderm.

Question 8

Protostomes

Answer 8

A bilaterian in which the blastopore, the first opening to the internal cavity of the developing embryo, becomes the mouth. The taxonomic name is Protostomia, and the group includes mollusks and arthropods.

Question 9

Deuterostomes

Answer 9

A bilaterian in which the blastopore, the first opening to the internal cavity of the developing embryo, becomes the anus. The taxonomic name is Deuterostomia and includes humans and other chordates.

Question 10

Coelom

Answer 10

A body cavity surrounding the gut.

Question 11

Tissue

Answer 11

A collection of cells that work together to perform a specific function.

Question 12

Organ

Answer 12

Two or more tissues that combine and function together.

Question 13

Epithelial tissue

Answer 13

A type of animal tissue that provides a lining for all of the spaces inside and outside the body; it is composed of closely packed cells.

Question 14

Connective tissue

Answer 14

A type of animal tissue that underlies epithelial tissues and is found elsewhere as well; it has an extensive extracellular matrix and few cells.

Question 15

Muscle tissue

Answer 15

A type of animal tissue made up of cells (fibers) that are able to shorten or contract, resulting in movement.

Question 16

Nervous tissue

Answer 16

A type of animal tissue found in the nerve nets of cnidarians and in the brain, spinal cord, and peripheral nerves of vertebrates; it takes in sensory information from the environment, processes information, and sends signals to target organs to elicit a response.

Question 17

Organ System

Answer 17

A group of organs that have related functions. For example, the intestine is one organ of the digestive system, which also includes the stomach, liver, pancreas, and other organs.

Question 18

Homeostasis

Answer 18

The active regulation and maintenance, in organisms, organs, or cells, of a stable internal physiological state in the face of a changing external environment.

Question 19

Negative Feedback

Answer 19

The effect in which the final product of a biochemical pathway inhibits the first step; the process in which a stimulus acts on a sensor that communicates with an effector, producing a response that opposes the initial stimulus. Negative feedback is used to maintain steady conditions, or homeostasis.

Question 20

Set Point

Answer 20

A steady-state value in homeostatic regulation.

Question 21

Cambrian Explosion

Answer 21

A transition period in geologic time during which the body plans characteristic of most bilaterian phyla diversified.

Question 22

Mass Extinction

Answer 22

A catastrophic drop in recorded diversity, which has occurred five times in the past 541 million years.

Question 23

Isometry

Answer 23

An increase in body size while keeping the same overall shape; literally, “same measure.”

Question 24

Allometry

Answer 24

An increase in body size accompanied by a change in shape; literally, “different measure.”

Question 25

T/F: Homologies are helpful for reconstructing evolutionary relationships because they show the evolutionary development of characters among groups.

Answer 25

True

Question 26

A tissue is a collection of:

Answer 26

cells that perform a specific function.

Question 27

“The ability to maintain a steady physiological state in the face of a changing environment” is the definition of:

Answer 27

Homeostasis

Question 28

T/F: Nearly all dinosaurs became extinct at the end of the Cretaceous Period as a result of direct competition with mammals.

Answer 28

False

Question 29

T/F: Circulation in your body is controlled through the action of the heart, lungs, arteries, and veins. Circulatory function in your body is controlled by an organ system.

Answer 29

True

Question 30

T/F: A woman is taking a hike and sees a rattlesnake appear on the path near her feet. She is startled and as a result, her heart rate increases and she runs in the opposite direction. The woman’s heart rate is able to increase because heart rate is not maintained through homeostasis.

Answer 30

False

Question 31

T/F: Coral reefs and tropical rain forests have existed on Earth for hundreds of millions of years, but the taxonomic composition of both has varied enormously.

Answer 31

True

Question 32

T/F: The division of bilaterians into coelomate, acoelomate, and pseudocoelomate groups is supported by molecular studies.

Answer 32

False

Question 33

T/F: All animal phyla are characterized by having their cells organized into different kinds of tissues.

Answer 33

False

Question 34

T/F: Body temperature is maintained within a specific range because many physiologic and cellular functions are optimal only within a specific range. If someone goes outside on a hot day, they begin to get hot and their body temperature can rise. The body can respond by producing sweat from sweat glands to try and cool the body down. The cooling of the body from the production of sweat provides negative feedback to the hypothalamus.

Answer 34

True

Question 35

On a phylogenetic tree, distantly related species diverge from branch points nearer to the tree’s:

Answer 35

base

Question 36

T/F: Nervous tissue is found in all animal phyla except poriferans.

Answer 36

True

Question 37

T/F: Different cells in the human body will maintain different homeostatic ion concentrations. These ion concentrations are controlled primarily by the composition and function of their cell membranes.

Answer 37

True

Question 38

________ growth in animals is seen as they get larger to accommodate changes in surface area to volume ratio that occur with larger size and the need to support more mass with increasing size.

Answer 38

Allometric

Question 39

T/F: A very healthy person should always have a constant heart rate and blood pressure.

Answer 39

False

Question 40

Speciation is the divergence of two populations from a common ancestor. How does it contribute to biological diversity?

Answer 40

Speciation increases biological diversity.

Question 41

The ability to maintain certain physical conditions (blood pH, body temperature, and so forth) within a narrow range of values most often depends on:

Answer 41

negative feedback

Question 42

On a phylogenetic tree, more closely related species branch from points ______ the tips of the tree.

Answer 42

closer to

Question 43

T/F: Patterns in early embryological development sometimes tell us more about phylogenetic relationships than adult characters.

Answer 43

True

Question 44

T/F: You find an organism that is previously unknown to you. You see that it has bilateral symmetry and, therefore, expect that it will have muscle tissue.

Answer 44

True

Question 45

Biologists have described about ___ species of eukaryotic organisms, of which about ___ are animals. The majority of eukaryotic species are ___.

Answer 45

1.8 million; 1.3 million; insects

Question 46

Connective tissue is formed of loosely connected cells and a large portion of extracellular matrix. The function of each specific type of connective tissue is related to:

Answer 46

the composition of the proteins in its extracellular matrix.

Question 47

T/F: With the exception of poriferans, all animal phyla contain true muscle tissue.

Answer 47

false

Question 48

Different groups of organisms are defined by the unique characters they possess. The relative timing of when a particular character arose can be estimated by determining:

Answer 48

shared presence of the character in descendants of the population in which the character first arose.

Question 49

T/F: Nervous tissue is found in all animal phyla except poriferans.

Answer 49

True

Question 50

Because they lack well-defined and complex organ systems, we hypothesize that _____ diverged from all other animals early in the evolution of animals.

Answer 50

Poriferans

Question 51

T/F: During childbirth the release of a hormone, oxytocin, causes an increase of uterine contractions. The increase in uterine contractions causes an increase in the amount of oxytocin produced and increasing strength of contractions. This is an example of negative feedback.

Answer 51

false