Chapter 5 Flashcards
classification
ordering of organisms into categories, such as orders, families, and genera, to show evolutionary relationships
Chordata
the phylum of the animal kingdom that includes vertebrates
vertebrates
animals with segmented, bony spinal columns; these include fishes, amphibians, reptiles (including birds), and mammals
homologies
similarities between organisms based on descent from a common ancestor
analogies
similarities between organisms based strictly on common function, with no assumed common evolutionary descent
homoplasy
(homo meaning “same”, plasy meaning “growth”); the separate evolutionary development of similar characteristics in different groups of organisms; ex: wings in butterflies and birds
evolutionary systematics
a traditional approach to classification (and evolutionary interpretation) in which presumed ancestors and descendants are traced in time by analysis of homologous characters
cladistics
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)
ancestral
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
clade
a group of organisms sharing a common ancestor; the group includes the common ancestor and all descendants
monophyletic
referring to an evolutionary group (clade) composed of descendants all sharing a common ancestor
polyphyletic
referring to an evolutionary group composed of descendants with more than one common ancestor (and thus not a true clade)
derived (modified)
referring to characters that are modified from the ancestral condition and thus diagnostic of particular evolutionary lineages
theropods
small to medium sized ground-living dinosaurs, dated to approx. 150 mya and thought to be related to birds
shared derived
relating to specific character traits shared in common between two life-forms and considered the most useful for making evolutionary interpretations
phylogenetic tree
a chart showing evolutionary relationships as determined by evolutionary systematics; it contains a time component and implies ancestor-descendant relationships
cladogram
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
biological species concept
a depiction of species as groups of individuals capable or fertile interbreeding but reproductively isolated from other such groups
speciation
the process by which a new species evolves from an earlier species; speciation is the most basic process in macroevolution
recognition species concept
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
ecological species concept
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
ecological niche
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
sexual dimorphism
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
intraspecific
within species; refers to variation seen within the same species
interspecific
between species; refers to variation beyond that seen within the same species to include additional aspects seen between two different species
paleospecies
species defined from fossil evidence, often covering a long time span
genus
a group of closely related species
fossils
traces or remnants of organisms found in geological beds on the earth’s surface
mineralization
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
taphonomy
study of how bones and other materials come to be buried in the earth and preserved as fossils
geological time scale
the organization of earth history into eras, periods, and epochs; commonly used by geologists and paleoanthropologists
continental drift
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
epochs
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)
neocortex
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
placental
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
heterodont
having different kinds of teeth; characteristic of mammals, whose teeth consist of incisors, canines, premolars, and molars
endothermic
able to maintain internal body temperature by producing energy through metabolic processes within cells; characteristic of mammals, birds, and perhaps some dinosaurs
adaptive radiation
the relatively rapid expansion and diversification of life-forms into new ecological niches
