Chapter 5

Question 1

classification

Answer 1

ordering of organisms into categories, such as orders, families, and genera, to show evolutionary relationships

Question 2

Chordata

Answer 2

the phylum of the animal kingdom that includes vertebrates

Question 3

vertebrates

Answer 3

animals with segmented, bony spinal columns; these include fishes, amphibians, reptiles (including birds), and mammals

Question 4

homologies

Answer 4

similarities between organisms based on descent from a common ancestor

Question 5

analogies

Answer 5

similarities between organisms based strictly on common function, with no assumed common evolutionary descent

Question 6

homoplasy

Answer 6

(homo meaning “same”, plasy meaning “growth”); the separate evolutionary development of similar characteristics in different groups of organisms; ex: wings in butterflies and birds

Question 7

evolutionary systematics

Answer 7

a traditional approach to classification (and evolutionary interpretation) in which presumed ancestors and descendants are traced in time by analysis of homologous characters

Question 8

cladistics

Answer 8

an approach to classification that attempts to make rigorous evolutionary interpretations based solely on analysis of certain types of homologous characters (those considered to be derived characters)

Question 9

ancestral

Answer 9

referring to characters inherited by a group of organisms from a remote ancestor and thus not diagnostic of groups (lineages) that diverged after the character first appeared; also called primitive

Question 10

clade

Answer 10

a group of organisms sharing a common ancestor; the group includes the common ancestor and all descendants

Question 11

monophyletic

Answer 11

referring to an evolutionary group (clade) composed of descendants all sharing a common ancestor

Question 12

polyphyletic

Answer 12

referring to an evolutionary group composed of descendants with more than one common ancestor (and thus not a true clade)

Question 13

derived (modified)

Answer 13

referring to characters that are modified from the ancestral condition and thus diagnostic of particular evolutionary lineages

Question 14

theropods

Answer 14

small to medium sized ground-living dinosaurs, dated to approx. 150 mya and thought to be related to birds

Question 15

shared derived

Answer 15

relating to specific character traits shared in common between two life-forms and considered the most useful for making evolutionary interpretations

Question 16

phylogenetic tree

Answer 16

a chart showing evolutionary relationships as determined by evolutionary systematics; it contains a time component and implies ancestor-descendant relationships

Question 17

cladogram

Answer 17

a chart showing evolutionary relationships as determined by cladistic analysis; based solely on interpretation of shared derived characters; contains no time component and does not imply ancestor-descendant relationships

Question 18

biological species concept

Answer 18

a depiction of species as groups of individuals capable or fertile interbreeding but reproductively isolated from other such groups

Question 19

speciation

Answer 19

the process by which a new species evolves from an earlier species; speciation is the most basic process in macroevolution

Question 20

recognition species concept

Answer 20

a depiction of species in which the key aspect is the ability of individuals to identify members of their own species for purposes of mating (and to avoid mating with members of other species); this type of selective mating is a component of a species concept emphasizing mating and is therefore compatible with the biological species concept

Question 21

ecological species concept

Answer 21

the concept that a species is a group of organisms exploiting a single niche; this view emphasizes the role of natural selection in separating one species from another

Question 22

ecological niche

Answer 22

the position of a species within its physical and biological environments; a species’ ecological niche is defined by such components as diet, terrain, vegetation, type of predators, relationships with other species, and activity patterns, and each niche is unique to a given species; together, ecological niches make up an ecosystem

Question 23

sexual dimorphism

Answer 23

differences in physical characteristics between males and females of the same species; ex: humans are slightly sexually dimorphic for body size, with males being taller, on average, than females of the same population; sexual dimorphism is very pronounced in many species, such as gorillas

Question 24

intraspecific

Answer 24

within species; refers to variation seen within the same species

Question 25

interspecific

Answer 25

between species; refers to variation beyond that seen within the same species to include additional aspects seen between two different species

Question 26

paleospecies

Answer 26

species defined from fossil evidence, often covering a long time span

Question 27

genus

Answer 27

a group of closely related species

Question 28

fossils

Answer 28

traces or remnants of organisms found in geological beds on the earth’s surface

Question 29

mineralization

Answer 29

the process in which parts of animals (or some plants) become transformed into stonelike structures; usually occurs very slowly, as water carrying minerals (such as silica or iron) seeps into the tiny spaces within a bone; in some cases, the original minerals within the bone or tooth can be completely replaced, molecule by molecule, with other minerals

Question 30

taphonomy

Answer 30

study of how bones and other materials come to be buried in the earth and preserved as fossils

Question 31

geological time scale

Answer 31

the organization of earth history into eras, periods, and epochs; commonly used by geologists and paleoanthropologists

Question 32

continental drift

Answer 32

the movement of continents on sliding plates of the earth’s surface; as a result, the positions of large landmasses have shifted drastically during the earth’s history

Question 33

epochs

Answer 33

categories of the geological time scale; subdivisions of periods; in the Cenozoic era, epochs include the Paleocene, Eocene, Oligocene, Miocene, and Pliocene (from the Tertiary Period) and the Pleistocene and Holocene (from the Quaternary Period)

Question 34

neocortex

Answer 34

the more recently evolved portions of the cortex of the brain that are involved with higher mental functions and composed of areas that integrate incoming information from different sensory organs

Question 35

placental

Answer 35

a type (subclass) of mammal; during the Cenozoic, placentals became the most widespread and numerous mammals and today are represented by upward of 20 orders, including the primates

Question 36

heterodont

Answer 36

having different kinds of teeth; characteristic of mammals, whose teeth consist of incisors, canines, premolars, and molars

Question 37

endothermic

Answer 37

able to maintain internal body temperature by producing energy through metabolic processes within cells; characteristic of mammals, birds, and perhaps some dinosaurs

Question 38

adaptive radiation

Answer 38

the relatively rapid expansion and diversification of life-forms into new ecological niches