Studied by 0 PeopleTags & Description
Macroevolution
the broad pattern of evolution above the species level
Protocell
an abiotic precursor of a living. ell that had a membrane-like structure and that maintained an internal chemistry different from that of its surroundings
Hydrothermal Vents
an area on the deep sea floor where heated water and minerals from Earth’s interior gush into the seawater
Alkaline Vents
a deep sea hydrothermal vent that releases water that is warm rather than hot and that has a high pH
Ribozymes
an RNA molecule that functions as an enzyme, such as an intron that catalyzes its own removal during RNA splicing
Radiometric Dating
a method for determining the absolute age of rocks and fossils, based on the half-life of radioactive isotopes
Half-Life
amount of time it takes for half of a sample of a radioactive isotope to decay
Geologic Record
a standard time scale dividing Earth’s history into time periods, grouped into four eons - Hadean, Archaean, Proterozoic, and Phanerozoicand further subdivided into eras, periods, and epochs
Stromatolites
layered rock that results from the activities of prokaryotes that bind thin films of sediment together
Endosymbiont Theory
the theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by a host cell. the engulfed cell and its host cell evolved into a single organism
Serial Endosymbiosis
a hypothesis for the origin of eukaryotes consisting of a sequence of endosymbiotic events in which mitochondria, chloroplasts, and perhaps other cellular structures were derived from a small prokaryotes that had been engulfed by larger cells
Cambrian Explosion
a relatively brief time in geologic history when many present-day phyla of animals first appeared in the fossil record. 535-525 million years ago, the emergence of the first large, hard-bodied animals
Plate Tectonics
the theory that the continents are part of great plates of earth’s crust that float on the hot, underlying portion of the mantle. movements in the mantle cause the continents to move slowly over time
Pangaea
the supercontinent that formed near the end of the Paleozoic era, when plate movements brought all the landmasses of Earth together
Mass Extinction
the elimination of a large number of species throughout Earth, the result of global environment changes
Adaptive Radiations
period of evolutionary change in which groups of organisms form many new species whose adaptions allow them to fill different ecological roles in their communities
Heterochrony
evolutionary change in the time or rate of an organism’s development
Paedomorphosis
the retention in an adult organism of the juvenile features of its evolutionary ancestors
Homeotic Genes
any of the master regulatory genes that control placement and spatial organization of body parts in animals, plants, and fungi by controlling the development fate of groups of cells
Phylogeny
the evolution of history of a species or group of related species
Systematics
a scientific discipline focused on classifying organisms and determining their evolutionary relationships
Taxonomy
a scientific discipline concerned with naming and classifying the diverse forms of life
Binomial
the two-part latinized format for naming a species, consisting of the genus and specific epithet
Linean Classification
Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species
Taxon
a named taxonomic unit at any given level of classification
Phylogenetic tree
a branching diagram that represents a hypothesis about the evolutionary history of a group of organisms
Phylocode
proposed system of classification of organisms based on evolutionary relationships: only groups that include a common ancestor and all of its descendants are named
Branch Points
the representation on a phylogenetic tree of the divergence of two or more taxa from a common ancestor
Rooted
describing a phylogenetic tree that contains a branch point representing the most recent common ancestor of all taxa in the tree
Basal taxon
in a specified group of organisms, a taxon whose evolutionary lineage diverged early in the history of the group
Polytomy
in a phylogenetic tree, a branch point from which more than two descendant taxa emerge. a polytomy indicates that the evolutionary relationships between the descendant taxa are not yet clear
Analogy
similarity between two species that is due to convergent evolution rather than to descent from a common ancestor with the same trait
Homoplasies
a similar structure or molecular sequence that has evolved independently in two species
Molecular Systematics
a scientific discipline that uses nucleic acids or other molecules to infer evolutionary relationships between different species
Cladistics
an approach to systematics in which organisms are placed into groups called clades based primarily on common descent
Clades
a group of species that includes an ancestral species and all of its descendants
Monophyletic
pertaining to a group of taxa that consists of a common ancestor and all of its descendants. a monophyletic taxon is equivalent to a clade
Paraphyletic
pertaining to a group of taza that consists of a common ancestor and some, but not all, of its descendants
Polyphyletic
pertaining to a group of taxa derived from two or more different ancestors
Shared Ancestral Character
a character, shared by members of a particular clade, that originated in an ancestor that is not a member of taht clade
Shared Derived Character
an evolutionary novelty that is unique to a particular clade
Outgroup
a species or group of species from an evolutionary lineage that is know to have diverged before the lineage that contains the group of species being studied. an outgroup is selected so that its members are closely to the group of species being studied, but not as closely related as any study-group members are to each other
Ingroup
a species or group of species whose evolutionary relationships we seek to determine
Maximum Parsimony
a principle that states that when considering multiple explanations for an observation, one should first investigate the simplest explanation that is consistent with the facts
Maximum Likelihood
as applied to molecular systematics, a principle that states that when considering multiple phylogenetic hypotheses, one should take into account the hypothesis that reflects the most likely sequence of evolutionary events, given certain rules about how DNA changes ove time
Orthologous Genes
homologous genes that are found in different species because of speciation
Paralogous Genes
homologous genes that are found in the same genome as a result of gene duplication
Molecular Clock
a method for estimating the time required for a given amount of evolutionary change, based on the observation that some regions of genomes evolve at a constant rate
Neutral Theory
the hypothesis that much evolutionary change in genes and proteins has no effect on fitness and therefore is not influenced by natural selection
Horizontal Gene Transfer
the transfer of genes from one genome to another through mechanisms such as transposable elements, plasmid exchange, viral activity, and perhaps fusion of different organisms
Peptidoglycan
a network of sugar polymers cross-linked by polypeptides
Gram Stain
used to classify bacteria by cell wall composition
Gram-Positive Bacteria
simpler walls with a large amount of peptidoglycan (stains purple)
Gram-Negative Bacteria
have less peptidoglycan and an outer membrane that can be toxic (stains red)
Capsule
the cell wall of many prokaryotes is surrounded by a sticky layer of polysaccharide or proteins
Endospores
a way of withstanding harsh conditions, certain bacteria develop resistant cell called this
Fimbriae
hairlike appendages that stick to substrates
Pili (sex-pili)
appendages that pull two cells together prior to DNA transfer from one cell to another
Taxis
the ability to move toward or away from a stimulus
Nucleoid Region
chromosome is located here
Plasmids
some species of bacteria also have smaller rings of independently replicating DNA called this
Three factors that contribute to genetic diversity
Rapid Reproduction, Mutation, Genetic Recombination
Genetic Recombination
the combining of DNA from two sources, contributes to diversity
Transformation
a prokaryotic cell can take up and incorporate foreign DNA from the surrounding environment
Transduction
the movement of genes between bacteria by bacteriophages (viruses that infect bacteria)
Conjugation
the process where genetic material is transferred between prokaryotic cells
F Factor
piece of DNA that is required for the production of pili
F Plasmid
cells containing this functions as DNA donors during conjugation
R Plasmid
carry genes for antibiotic resistance
Phototrophs
obtain energy from light
Chemotrophs
obtain energy from chemicals
Autotrophs
require CO2 as a carbon source
Heterotrophs
require an organic nutrient to make organic compounds
Obligate Aerobes
require O2 for cellular respiration
Obligate Anaerobes
are poisoned by O2 and use fermentation or anaerobic respiration
Facultative Anaerobes
can survive with or without O2
Nitrogen Fixation
some prokaryotes convert atmospheric nitrogen (N2) to ammonia (NH3)
Heterocysts
nitrogen-fixing cells
Extreme halophiles
live in highly saline environments
Extreme Thermophiles
thrive in very hot environments
methanogens
live in swamps and marshes and produce methane as a waste product
Decomposers
breaking down dead organisms and waste products
Symbiosis
an ecological relationship in which two species live in close contact. a large host and a smaller symbiont
Mutualism
both symbiotic organisms benefit
