BIO 181 EXAM 3

Systematics

The science of classifying organisms based on their evolutionary relationships.

Taxonomy

The science of classifying, naming, and describing organisms.

Phylogeny

The evolutionary history and relationships among a species or group of species.

Taxonomic Ranks

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Three Domains of Life Back

Bacteria, Archaea, and Eukarya

Binomial Nomenclature

A two-part scientific naming system using the Genus and species names

Phylogenetic Tree

A diagram used to show the evolutionary relationships among organisms.

Rooted Phylogentic

A tree with a single branch point at the base representing the common ancestor of all taxa shown.

Branch Point

A point on a phylogenetic tree where a split occurs, representing the divergence of two lineages from a common ancestor.

Sister Taxa

Two lineages that stem from the same branch point on a phylogenetic tree.

Basal Taxon

A lineage that diverges early in the history of a group and originates near the root of the tree.

Taxon

A group of organisms at any level of the taxonomic hierarchy (e.g., species, family, order).

Homologous Structure (homology)

A similarity in organisms due to shared ancestry.

Analogous Structure (analogy / homoplasy)

A similarity in organisms due to convergent evolution (similar pressures), not shared ancestry.

Cladistics

A system of classification that groups organisms based on shared derived characters.

Clade

A group of organisms believed to have evolved from a single common ancestor.

sister clades

share an immediate CA; each other’s closest relatives

Cladogram 

Diagram showing similarities and evolutionary relationships among organisms

Shared Ancestral Character

A character that is found in the ancestor of a group and all organisms in that taxon or clade.

Shared Derived Character

An evolutionary novelty unique to a particular clade, not found in the ancestor.

Maximum Parsimony

The principle that the simplest explanation, involving the fewest evolutionary events (changes), is the most likely tree.

Horizontal Gene Transfer

The transfer of genetic material between unrelated species, common in prokaryotes.

Ingroup

The group of species (taxa) of primary interest when constructing a phylogenetic tree.

Outgroup

A species or group from a lineage known to have diverged before the ingroup; used to determine ancestral vs. derived traits.

Monophyletic

Includes the most recent common ancestor and all of its descendants.

Paraphyletic

includes the most recent common ancestor but not all of its descendants.

Polyphyletic

Includes descendants from different ancestors, but not their common ancestor.

Common nickname for prokaryotes

mircobes

cellularity of most prokaryotes

virtually all unicelluar

key celluar features of prokaryotes

cell wall no true nucleus or organelles

prokaryote size vs. eukaryotes

smaller and more abundant that eukaryotes

example of extreme habitats for archaea

thermophilic (heat loving), halophilic (salt- loving)

typical number of mircobes in a teaspoon of soil

billions of microbes

a major ecological role of prokaryotes

decomposer

prokaryote role in aquatic environments

part of plankton

the two domains of prokaryotes 

bacteria and archaea

prokayotic movement in response to stimuli

taxis

structure of main prokaryotic DNA

Ring of DNA (chromosome)

size of prokaryotic DBA ring vs. Eukaryotic

0.001 x that of eurkayote

plasmids

DNA molecules different from chromosomal DNA that replicate

typical prokaryotic divison time

most divide 1 to 3 hours; some 20 minutes

prokaryotic survival structure in hars enviroments

endospores

heat resistance of some endospores

survive boiling water

how prokaryotes adapt quickly

adapt quickly to environment through natural selection

three domain system 

bacteria, archaea, eukaryotes

examples of organisms in the eurkaryote domain

plants, fungi, animals, protoza

estimated total number of species on Earth 

10 to 14 milion

estimated total species

1 trillion species

number of documented species

1.2 milion

percentage of species estimated to be undescribed

86%

percentage of species described

one thousandth of 1 % described

ancestral trait

in ancestor of grouo may be retained or changed in descendants

derived trait 

differs from ancestral form; evolutionary novelty

haploid

one set of chromosomes

diploid

two set of chromosomes

gametes

sex cells

gametophyte

gamete producing structure

meiosis

cell division process ; yeilds haploid gametes or spores

mitosis

cell division process; yields identical cells

synapsids

mammals, 1 temporal

sauropsids

anapsids and diapsids

anapsids

no. temporal fenstrae, turtles

diapsids

2 temporal fenstrae

endosymbiosis

The main organelles of a eukaryotic cell evolved from tiny primitive prokaryotic cells that had been engulfed by different, larger prokaryotic cells.

chytrids

Common in freshwater  environments; have  enzymes that digest  cellulose so they are  important decomposers  of plant tissues; can live  in the guts of herbivores  to help digest their food;  have a flagellated stage  called a zoospore that  produces and holds  spores.

Zygote fungi

Soil dwellers  (lakes and wet  soils); comprise  the common  bread molds and  fruit rots; are  decomposers,  parasites, and  mutualists; form  zygospores that  are resistant to  harsh conditions;  can form  mycorrhizal  associations

arbuscular mycorrhizal fungi

Mycorrhizal  fungi; 90%  of plants  have  relationships  with these  fungi

sac fungi

sac fungi; found  in diverse  habitats  (terrestrial &  aquatic); 70% of  all fungi belong  to this group;  spores are in sacs  called asci;  includes yeast,  truffles, morels,  and Penicillium  spp.; some are  mycorrhizal; can  form lichens; can  cause disease

club fungi

Typical mushroom spp.;  also include shelf/bracket  fungi, some molds, and  rusts; named for basidia  that are club-like cells  where spores form; have  mycorrhizal associations  and lichens; some are  mutualistic with insects

diploblasts

ecotoderm

endoderm