EFB 101 Exam #2 Key Terms

Taxon

Formal grouping at any level

Phylogeny

The evolutionary relationship between organisms

Binomial Nomenclature

A two-part naming system

What is correct binomial nomenclature?

Genus species

Monophyletic group

A group with a common ancestor and ALL of it’s decendents

Polyphyletic group

All the groups’ species and NOT the common ancestor

Paraphyletic group

One ancestral species, and SOME of their descendents

Nodes

A common ancestor; where lineages diverse

Sister Taxa

Share an immediate common ancestor not shared by any other group; each others closest relative

Basal taxon

A lineage that diverges from all other groups early; most related to original species

Polytomy

More than 2 branches from a single node

Apomorphy

Derived character state different than that of the ancestor

Plesiomorphy

Character state present in a distant common ancestor

Autapomorphy

Derived character unique to a particular taxon

Synapomorphy

Derived character in 2 or more taxa as a result of a common ancestor

Homoplasy

Derived character shared by 2 or more organisms, but did not arise from common ancestry

Ingroup

Group actively trying to be organized

Outgroup

Related to ingroup, but branch off earlier

Parsimony

The explanation which requires the fewest evolutionary changes is the best

Molecular clock

Method to estimate time required for evolutionary changes, based on constant genome evolution

Homologous structures

Similar structures because of common ancestry

Analogous structures

Similar structures that evolved independently

Shared ancestral characters

Ancestral character shared by multiple taxa (evolved a long time ago)

Shared derived character

Derived characters present in multiple taxa because of a common ancestor

Phylogenetic bracketing

The prediction of traits of an extinct organism by looking at the traits of the closest living relatives

Synapomorphy

A trait that appeared in a more recent common ancestor, and is unique to members of a particular clade

Symplesiomorphy

A shared ancestral character shared across multiple groups

Two major domains of prokaryotes?

Bacteria and archea

What defines a prokaryote

No nucleus, no membrane bound organelles, cell wall (peptidoglycan)

Cilia

Hair-like membrane protrusions that aid with movement

Flagella

Whip-like protrusion that aids in movement. Motor, hook, and filament.

Tumbling

Clockwise rotation of flagella. Used for orientation

Running

Counterclockwise tumbling of flagella. Used for movement.

Taxis

Directed movement to/from stimulus

Vesicles

Membranous sac in prokaryotes that helps with transport, storage, and organization.

Bacteriostatic

Inhibits growth

Bactericidal

Kills bacteria

Exotoxins

Toxin released outside of cells

Endotoxins

Toxins produced insides cells

Transformation

Uptake foreign DNA from surroundings

Transduction

Phages carry prokaryotes genes from host and attach them to bacterial cells

Conjugation

DNA transferred through 2 cells temporarily joined

Cyanobacteria

Gram negative bacteria that provided the atmosphere with oxygen early on in earth’s history

Extremophiles

Living in extreme conditions

Thermophiles

Living in very hot conditions

Halophiles

Living in very salty conditions

Methanogens

Produce ATP

Rod shaped

Bascillus

Shperical

Cocci

Spiral

Spirilli

Gram Positive Bacteria

Thick later of peptidoglycan, simple cell walls (PURPLE)

Gram Negative Bacteria

Less peptidoglycan, more complex (PINK)

Obligate aerobes

Must use oxygen for respiration

Obligate anaerobes

Poisoned by oxygen

Facultative anaerobes

Can use, or not use, oxygen

Photoautotroph

Light as energy source, CO2 as carbon source

Chemotroph

Inorganic chemical as energy source, CO2 as carbon source

Photoheterotroph

Light as energy source, organic compounds as carbon source

Chemoheterotroph

Organic compounds as light and energy source

Endosymbiosis

Eukaryotic cells evolved organelles when smaller prokaryotic cells were engulfed

Cyanobacteria

Photosynthetic bacteria

Plankton

Protists, bacteria, archaea

Pseudopods

Cell extension that uses the cytoskeleton to squeeze cytoplasm forward

Homeobox (hox) genes

Regulatory genes that control developmental/locomotion structures

Diploblasty

Two tissue types

Ectoderm

Outside tissues

Endoderm

Inside tissues

Radial symmetry

No front, back, left, right

Bilateral symmetry

Can be divided into two mirror halves

Protostomes

Mouth forms first

Mesoderm

Middle layer of cells between ectoderm and endoderm. Forms muscle

Coelom

Body cavity that may be filled with air or fluid. Lined with the mesoderm

What primarily defines lophotrochozoa?

Growing continuously

What primarily defines ecdysozoa?

Molting/ ecdysis