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AN101 Chapter 5
Chapter 5 terms and definitions
Terms in this set (42)
large-scare evolutionary processes.
In biology, the ordering of organisms into categories, such as orders, families, and genera, to show evolutionary relationships.
Organisms that can move about and ingest food (but don't photosynthesize, as do plants)
Multi-cellular animals' a major division of the animal kingdom.
Within Metazoa there are more than 20 major groups called phyla (singular- phylum)
One of the phyla of the Metazoa.
The phylum of the animal kingdom that includes vertebrates.
animals with a nerve cord, gill slits (at some stage of development) and a supporting cord along the back.
Most chordates are called vertebrates becase they have a vertebral column.
Animals with segmented, bony spinal columns; includes fishes, amphibians, reptiles, birds and mammals.
Vertebrates have also developed brain and paired sensory structures for sight, smell and balance.
the field that specialixes in establishing the rules of classification
Organisms are classified first, and most traditionally, based on their physical similarities (Such was the basis for the first systematic classification devised by Linnaeus in the 18th Century)
Evolution of the Forearm
Forelimb development in vertebrates is directed by just a few regulatory genes.
Homologies. The similarities in the forelimb bones of certain animals can be most easily explained by descent from a common ancestor.
Basic genetic regulatory mechanisms are highly conserved in animals; they've been maintained relatively unchanged for millions of years.
Structures that species share based on their descent from a common ancestor.
Reliable indicators of evolutionary relationship.
Similarities between organisms based strictly on common function, with no assumed common evolutionary descent.
Ex: Both butterflies and birds have wings. But, they differ dramatically. (Birds have an internal skeleton, central nervous system, and four limbs, insects don't) Their superficial similarities are a product of separate evolutionary response to roughly similar functional demands. (Homoplasy)
The process that leads to the development of analogies (analogous structures) wish as wings in birds and butterflies.
"Homo" meaning "same" and "plasy" meaning "growth"
The separate evolutionary development of similar characteristics in different groups of organisms.
A more traditional approach to classification (and evolutionary interpretation) in which presumed ancestors and descendants are traces in time by analysis of homologous characters.
Emerged Primarily in the last 20 years.
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)
Main difference from Evolutionary Systematics: Cladistics more rigorously defines the kinds of homologies that provide the most useful information.
Ex: At a very basic level, all life forms share DNA as the molecule underlying all biological processes. However, beyond implying that all life most likely derives from a single origin, the presence of DNA tells us nothing else about more specific relationships among different kinds of life-forms.
Important point: Some homologous characters are much more informative than others.
Focuses on traits that are far more informative- those that distinguish particular evolutionary lineages.
Ex:General ancestral bony pattern of the forelimb in land animals with backbones doesn't allow us to distinguish among them, but further modification in certain groups does (hooves, flippers, wings)
specific features with which organisms should be compared.
also called 'traits'
Primitive or Ancestral traits
Referring to characters inherited by a group of organisms from a remote ancestor and this not diagnostic of groups (lineages) that diverged after the character(trait) first appeared.
Ex: Forelimb bone arrangement. Useful in showing us they are related through a distant ancestor but don't provide any usable info that lets us distinguish one from another (ex a reptile from a mammal)
A character(trait) seen in two organisms is inherited in both of them from a distant ancestor.
Derived or Modified Traits
Referring to characters that are modified from the ancestral condition and this ARE diagnostic of particular evolutionary lineages.
In comparing mammals with other vertebrates, presence of fur is a derived characteristic.
Shared Derived Characteristics
grouping two forms together - a bat and a mouse when they show shared derived characteristics - here, both possessing fur.
Relating to specific character states shared in common between two life-forms and considered the most useful for making evolutionary interpretations.
Phylogenetic Tree (Phylogeny)
A chart showing evolutionary relationships as determined by evolutionary systematics. It contains a time component and implies ancestor-descendant relationships.
Strict cladistic analysis shows relationships using a cladogram.
A chary showing evolutionary relationships as determined by cladistic analysis. It is based solely on interpretation of shared derived characters. it contains no time component and does NOT imply ancestor-descendant relationships.
Does not indicate time.
Biological Species Concept
A depiction pf species as groups of individuals capable of fertile interbreeding, but reproductively isolated from other such groups.
The view most zoologists prefer.
The process by which a new species evolves from a prior species.
Speciation is the most basic process in macroevolution.
According to the Biological Studies Concept, the way new species are first produces involves some kind of separation.
Eg Geographical, behavioral
A geographical barrier, such as a river, a mountain range, or even just a large distance, effectively separates two populations making gene exchange between them limited or impossible.
Example: Behavioral differences that interfere with courtship.
A Still Living Primate
Differences in physical characteristics between males and females of the same species.
These can result in markes variation in body size and proportions in adults 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.
A group of interbreeding or potentially interbreeding organisms that is reproductively isolated from other such groups.
within species; refers to variation seen within the same species.
Ex: individual, age and sex differences
Between species; refers to variation beyond seen within the same species to include additional aspects seen between two different species.
variation represent differences between reproductively isolated groups
Species defined from fossil evidence, often covering a long time span.
A group of closely related species.
Broader level of classification.
A group of species composed of members more closely related to each other than they are to species from any other genus.
Species that are members of the same genus share the same broad adaptive zone.
geological time scale
The organization of earth history into eras, periods and epochs; commonly used by geologists and paleoanthropologists.
First vertebrates are present in fossil record - 500mya
Several varieties of fishes(including ancestors of modern sharks and bony fishes), amphibians and reptiles appeared.
At the end of the Paleozoic, near 250mya, several varieties of mammal-like reptiles were diversifying. ( THEORY Some of these forms gave rise to mammals)
Late Paleozoic - Continents merged to form Pangea.
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.
Theory of Plate Tectonics
Early - the southern continents began to split off forming Gongwanaland. (South America, Africa, Anarctica, Australia, India)
the northern continents formed Laurasia. (North America, Greenland, Europe, Asia)
By end of era, continents were beginning to assume their current positions.
the positions of species within their physical and biological environments, together making up the ecosystem. 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.
Late Mesozoic - 70mya
A type (subclass) of mammal.
During the Cenozoic, placentals became the most widespread and numerous mammals and today are represented by upwards of 20 orders, including the primates.
Age of Mammals
Development of mammilian brain
Slower growth in utero and after birth.
Having different kinds of teeth; characteristic of mammals, whose teeth consist of incisors, canines, premolars, and molars.
Allows mammals to process a wide variety of foods.
"endo" meaning "within" or "internal"
Able to maintain internal body temperature through the production of energy by means of metabolic processes within cells; characteristic of mammals, birds and perhaps some dinosaurs.
young are born extremely immature and must complete development in an external pouch.
relatively rapid expansion and diversification of life-forms into new ecological niches.
The concept that evolutionary change proceeds through long periods of stasis punctuated by rapid periods of change.
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