Exam 1 Flashcards
Evolution
The change in allele frequencies in a population over time
selection
Change in allele frequencies due to organisms with advantageous alleles reproducing more successfully than organisms with other alleles
Genetic Drift
Random changes in allele frequencies in a population
Mutation
The source of a new allelic diversity
Migration
Movement of alleles between populations
Adaptation
A trait that evolves by selection for a particular function (because it increases fitness) from an ancestor that did not have that trait.
Phylogeny
the evolutionary relationships of a group of organisms (species level and higher)
Phylogenetic tree
diagram of ancestral relationships among species . Describes patterns and provides information about when large events occurred.
Taxonomy
Ordered division and naming of organisms
Taxon
A taxonomic unit at any level of hierarchy
Character
Evidence used to construct a tree (morphological, behavior, chemical composition, chromosome number, DNA)
Character state
Variation among characters
Branch point
divergence of two species
Sister taxa
groups that share an immediate common ancestor
Rooted tree
Includes a branch to represent the last common ancestor of all taxa in the tree
Polytomy
A branch from which more than two groups emerge
Monophyletic Clade
Ancestor and all of its descendants
Paraphyletic Clade
Ancestor and not all of its descendants (one or more is cut off)
Polyphyletic Clades
two or more animals, and not their ancestor.
Systematics
The study of evolutionary relationships between organisms
Outgroup
A group of species that is closely related to, but not a member of, the group under study
Classification
Uses information from systematics to place organisms into taxonomic groups
Population
A group of individuals of the same species living in the same area
Population Ecology
Focuses on the factors affecting how many individuals of a species live in an area (mathematically based)
Community
a group of interacting populations of different species in an area
Community ecology
Deals with the whole array of interacting species in a community
Symbiosis
Long, close relationship between two species. Can be mutualistic (positive, positive), commensal (positive, neutral), or parasitic (positive, negative)
Parasitism
Receiving resources from a host without directly killing the host
Ecosystem Ecology
emphasizes energy flow and chemical cycling among the various biotic and abiotic components
Ecosystem
the community of organisms in an area and the physical factors with which they interact
Dispersal
The movement of individuals
What makes an animal?
Multicellular, heterotrophic, eukaryotic, Tissues developed from embryonic layers.
Zygote
Single cell from fertilization
Blastula
Hollow ball of cells formed by cleavage
Gastrula
Embryo has one end fold inward and layers of tissues form
Gastrulation
Folding of embryo into layers
Ectoderm
covers the surface and becomes the outer covering and in some phyla the central nervous system
Endoderm
innermost germ layer that lines the digestive tract and organs such as the lungs and liver in vertebrates
Mesoderm
the third layer (between the other two) forming muscles and most other organs. (Not all animals have mesoderm)
Bilateral Symmetry
two-sided symmetry.
Dividing plane is sagittal plane, dorsal (top) side and ventral (bottom) side.
Right and left side
Anterior (head) and posterior (tail) ends
Cephalization
The development of a head
Diploblastic
having only 2 germ layers, radial organisms
Triploblastic
Having 3 germ layers, common to all bilaterally symmetric animals
Coelem
fluid or air filled space separating digestive tract from outer body wall
True coelem
formed from mesoderm
Coelemates
animals with a true coelem
pseudocoelomate
if the coelom is formed from both ends and mesoderm tisse
aceolomate
Of a triploblast lacks a body cavity
Protostome
(first mouth) development spiral cleavage deterministic cleavage cells are rigidly cast early in development mesoderm cells split then for coelom blastopore becomes the mouth
Deuterostome
(second mouth) development Radial cleavage indeterminate cleavage If very early embryo's cells are removed they will produce complete individual Blastopore becomes anus
Tissues
collections of specialized cells isolated by membranous layers
arise from germ layers
Neoproterozoic Era
(1 BYA - 542 MYA)
Ediacaran Biota
Paleozoic Era (542 - 251 MYA)
Cambrian Explosion
First fossils of arthropods, chordates, and echinoderms
Mesozoic Era
(251 - 65.5 MYA)
Dinosaurs and other animals
Cenozoic Era
(65.5 MYA - Today)
Order of Animal History Eras
Neoproterozoic, Paleozoic, Mesozoic, Cenozoic
