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Bio182 Test 2
Terminology for test 2
65
Biology
Undergraduate 1
04/11/2010

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Term
Obligate aerobe
Definition
Require O2 for cellular respiration
Term
Obligate anaerobe
Definition

Poisoned by O2

Uses fermentation or anaerobic respiration

Term
Facultative anaerobe
Definition

Can use O2 if present, but

Can do fermentation or anaerobic respiration if needed

Term
Mutualism
Definition
Form of symbiosis in which both organisms benefit
Term
Commensalism
Definition
Form of symbiosis in which one organism benefits, while neither harming or helping the other
Term
Parasitism
Definition
A type of symbiosis in which the parasitic organism benefits at the expense of the host, but does not kill the host
Term
Pathogen
Definition
Causes disease
Term
Exotoxin
Definition

Toxin secreted by a microorganism

Can cause damage even when the microorganism is not present

Term
Endotoxin
Definition
Released when the microorganism dies and the cell wall breaks down
Term
Phototroph
Definition
Obtains energy from light
Term
Chemotroph
Definition
Obtains energy from chemicals
Term
Autotroph
Definition
Requires CO2 as a carbon source
Term
Heterotroph
Definition
Requires an organic carbon source to make organic compounds
Term
Photoautotrophy
Definition
Reqires light as an energy source and CO2 as a carbon source
Term
Chemoautotrophy
Definition
Requires inorganic compounds as an energy source and COas a carbon source
Term
Photoheterotrophy
Definition
Requires light as an energy source and organic compounds as a carbon source
Term
Chemoheterotrophy
Definition
Requires organic compounds as an energy and carbon source
Term
R plasmids
Definition
Carry genes for antibiotic resistance on a plasmid
Term
Transformation
Definition
Uptake of foreign DNA from surroundings
Term
Transduction
Definition
Bacteriophage carry genes from one bacteria to another
Term
Conjugation
Definition
Genetic material is transferred between 2 bacteria that are temporily joined by a sex pili
Term
Taxonomy
Definition
The scientific discipline of naming and classifying organisms
Term
Phylogeny
Definition
The evolutionary history of a species or group of related species
Term
Systematics
Definition
Classifies organisms and determines their evolutionary relationships
Term
PhyloCode
Definition

Developed by systematists because Linnaean classification and phylogeny can differ

Only recognizes groups that include a common ancestor and all its descentdents. It does not have labels such as phylum, class, order, etc

Term
Sister taxa
Definition
Groups that share an immediate common ancestor
Term
Polytomy
Definition

A branch from which more than two groups emerge.

It indicates that the evolutionary relationships among the descendent taxa are not yet clear

Term
Phylogenetic trees do not:
Definition

Indicated when a species evolved

How much genetic change occurred in a lineage

Show that a taxon evolved from the taxon next to it

Term
Homolgy
Definition
Similarity due to shared ancestry
Term
Homoplasy (analogy)
Definition
Similarity due to convergent evolution, similarity in function
Term
Cladistics
Definition
Grouping organisms by common descent
Term
Clade
Definition

A group of species that includes an ancestral species and all its descendents

Shared homologous characters are used to construct clades

Term
Monophyletic
Definition
A valid clade that consists of the ancestor species and all its descendents
Term
Paraphyletic
Definition
Consists of an ancestral species and some, but not all the desendants
Term
Polyphyletic
Definition
Consists of various species that lack a common ancestor
Term
Plesiomorphy
Definition
Shared ancestral character
Term
Apomorphy
Definition
Derived character; Novel character
Term
Synapomorphy
Definition

Shared derived character

An evolutionary novelty unique to a particular clade

Term
Outgroup
Definition
Species or group of species that is closely related the ingroup (the various species being studied)
Term
Phylogram
Definition
A phylogenetic tree in which the branch length reflects the number of genetic changes that have taken place in a particular DNA sequence in that lineage
Term
Chronogram
Definition
A phylogenetic tree in which branch length represents chronological time
Term
Phylogenetic bracketing
Definition

Predicts features of an ancestor from features of its descendents

This has been applied to infer features for dinosaurs from their descendents, birds and croccodiles

Term
Orhologous genes
Definition
Homologous genes found in different species due to speciation. Can diverge only after speciation occurs.
Term
Paralogous genes
Definition
Result from gene duplication, so are found in more than one copy in the genome. They can diverge within the clade that carries them and often evolve into new functions.
Term
Molecular Clock
Definition

Use constant rates of evolution in some genes to estimate the absolute time of evolutionary change.

 

In orthologous genes, nucleotide substitutions are proportional to the time since they last shared a common ancestor

 

In paralogous genes, nucleotide substitutions are proportional to the time since the genes became duplicated.

 

Term
Neutral Theory
Definition
States that much evolutionary change in genes and proteins has no effect on fitness, and therefore is not influenced by Darwinian selection. The rate of molecular change in these genes and proteins should be more regular like a clock.
Term
Horizontal gene transfer
Definition
Movement of genes from one genome to another; complicating efforts to build a tree of life
Term
Macroevolution
Definition
The pattern of evolution over a long time range
Term
Top Hypothesis for the Chemical Evolution of Life
Definition

1. Reducing Atmosphere

2. Thermal Vents

3. Extraterrestrial "seeding" - panspermia

4. Ice covered ocean

Term
Protobionts
Definition

Agrregates of abiotically produced molecules surrounded by a membrane or membrane-like structure.

 

Those created in labs exhibit simple reproduction, metabolism, and maintain an internal chemical environment

Term
Radiometric dating
Definition

Can be used to determine the absolute age of a fossil, based on the decay of a radioactive isotope.

 

A "parent" isotope decays to a "daughter" isotope at a constant rate. The rate of decay is expressed by the half-life: the time required for 50% of the parent isotope to decay.

Term
Stromatolites
Definition
Layered rock that results from the activities of prokaryotes that bind thin films of sediment together.
Term
Serial endosymbiosis
Definition

Hypothesis for the origin eukaryotes consisting of endosymbiotic events in which mitochondria and chloroplasts were derived from small prokaryotes that had been engulfed by larger cells

 

An alpha-protobacteria became mitochondria

A cyanobacteria became a plastid

Term
Permian extinction
Definition

Defines boundary between Paleozoic and Mesozoic eras

 

It is thought that it was caused by a huge volcano in Serbia

Term
Cretaceous Extinction
Definition

Marks the boundary between the Mesozoic and Cenozoic Eras.

 

Caused by a comet, meteor, or asteroid in they Yucatan Peninsula.

 

Caused dinosaur extinction

Term

Consequences of Continental Drift

 

Definition

1. Reduction in shallow water habitat

2. Colder, drier climate inland

3. Changes in climate as continents move toward and       away from poles

4. Changes in ocean circulation patterns leading to global cooling.

Term
Consequences of Mass Extinctions
Definition

1. Alters ecological communities and niches available to organisms

2. Can take 5-100 million yrs for diversity to recover

3. Can pave the way for adaptive radiations

Term
Adaptive Radiations
Definition
Evolution of diversely adapted species from a common ancestor upon introduction to new environmental opportunities
Term
Heterochrony
Definition
Evolutionary change in rate or timing of activation of developmental genes
Term
Paedomorphism
Definition

Rate of reproductive development accelerates compared to somatic development

 

It results in the retention of juvenile characters in the adult

Term
Neotony
Definition
Somatic development is slowed. This results in juvenile characteristics well into maturity
Term
Progenesis
Definition
Reaches sexual maturity in its juvenile stage, and never attains its adult form
Term
Post displacement
Definition
Reaches sexual maturity first, and then develops the adult form
Term
Homeotic genes
Definition

Genes that determine which parts of the body forms which body parts

 

Term
Hox genes
Definition
A class of homeotic genes that provide positional info in an animal embryo
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