Studied by 9 people
phylogeny
evolutionary history of a species or group of related species
taxonomy
ordered division and naming of organisms
systematics
scientific discipline of classifying organisms and determining their evolutionary relationships and history of different species
carolus linnaeus
he published a system of taxonomy; named over 13,000 species or organisms; grouping into broad categories
domain, kingdom, phylum, class, order, family, genus, species
Name the 8 major taxonomic groups from broad to narrow (largest to smallest)taxon
taxon
a rank or group in a biological classification into which taxonomists classify related organisms.
B
The various taxonomic levels (genera, classes, etc.) of the hierarchical classification system differ from each other on the basis of
A) how widely the organisms assigned to each are distributed throughout the environment.
B) their inclusiveness.
C) the relative genome sizes of the organisms assigned to each.
D) morphological characters that are applicable to all organisms
bacteria, archaea, eukarya
Name the 3 domains of life
genus
a principal taxonomic category that ranks above species and below family, and is denoted by a capitalized Latin name
specific epithet
species identifier, what group in the genus are we talking about?
phylogenetic tree
a hypothesis about the evolutionary relationships between taxa -- they can change all the time
vertical or diagonal
what are the 2 different forms of phylogenetic trees
branch point
this is the part of the phylogenetic tree where lineages diverge
hatch marks
thie refers to traits that might have evolved from the past; homologous characteristic shared by all the groups to the right of the mark
sister taxa
taxa that are each other’s closest relatives; share exclusive common ancestor
basal taxa
1st thing to split off from the root (doesn’t usually split anymore)
polytomy
an unresolved pattern of divergence
cladistics
a system of constructing phylogenetic trees using shared characters and inferred common ancestry
clade
a group of species that includes an ancestral species and all its descendents - monophyletic
shared ancestral character
a character that originated in an ancestor prior to the clade of interest; ancestral state
shared derived character
character that is novel to a particular clade (synapomorphy)
ingroup
species or group of species being studied in a phylogenetic analysis
outgroup
species or group of species that is closely related to the ingroup but diverged before the ingroup
parsimony
assumes fewest evolutionary changes over time
maximum likelihood
includes likelihood of certain types of mutations and changes
homology
similarity due to shared ancestry between a pair of structures or genes in different taxa
analogy
similarity of function and superficial resemblance of structures that have different origins.
molecular clock
a method of estimating the date of past evolutionary events based on the amount of genetic change or divergence
peptidoglycan
bacterial cell walls contain _____ a network of polysaccharides cross-linked by polypeptides
taxis
ability to move toward/away from a stimulus
chemotaxis
movement toward/away from a chemical stimulus
phototaxis
movement toward/away light
plasmids
small circular pieces of DNA
rapid reproduction, mutation, genetic recombination
What factors contribute to prokaryotic genetic variation?
transformation
prokaryotic cell takes up and incorporates foreign DNA from environment
transduction
movement of genes between bacteria by bacteriophages
conjugation
genetic material is transferred between prokaryotic cells
C
Which of these statements about prokaryotic genetics is true?
A) Bacterial cells conjugate to mutually exchange genetic material.
B) Their genetic material is confined within vesicles known as plasmids.
C) They divide by binary fission without mitosis or meiosis. D) Genetic variation in bacteria is not present because of their asexual mode of reproduction.
phototrophs
obtain energy from light
chemotrophs
obtain energy from chemicals and organic molecules are obtained
autotrophs
require CO2 as a carbon source
heterotrophs
require organic nutrients to make organic compounds
obligate aerobes
require O2
obligate anaerobes
poisoned by O2
facultative anaerobes
can survive with or without O2, but grow best with O2
aerotolerant
can survive with or without O2 and show no difference in growth with or without O2
extremophiles
extreme environments
halophiles
live in highly saline environments
thermophiles
thrive in very hot environments
methanogens
live in swamps and marshes and produce methane as a waste product
bacterial species concept
genomic and phenotypic consistency
gram-positive
bacteria have simpler cell walls with a large amount of peptidoglycan; have a thick layer of peptidoglycan and appear purple as it absorbs a lot of dye; circular shape
gram-negative
bacteria have less peptidoglycan; have two cell membranes with walls in between; thin layer of peptidoglycan; appear pink as it absorbs less dye; elongated, rod tubular shape
symbiosis
ecological relationship in which two species live in close contact, a larger host and smaller symbiont
mutualism
both symbiotic organisms benefit
commensalism
one organism benefits while neither harming nor helping the other
parasitism
one organism (the parasite) harms its host
decomposers
organism that breaks down dead organic material
endosymbiotic theory
a class of hypotheses that view various organelles in eukaryotic cells as descendants of endosymbionts
prokaryotes
these cause about half of all human diseases
B
In general, what is the primary role of prokaryotes when considering the overall flow of chemicals and matter through ecosystems?
A) parasitizing eukaryotes, thus causing diseases
B) breaking down organic matter
C) metabolizing materials in extreme environments
D) serving as primary producers in terrestrial environments
host
a living organism that acts as a harbour for invading pathogenic organisms.
symbiont
any of several living arrangements between members of two different species, including mutualism, commensalism, and parasitism.
spherical, rod-shaped, spiral
what are the three different bacteria shapes?
parasite
an organism that lives on or in a host organism and gets its food from or at the expense of its host.
monophyletic group
includes an ancestor and all of its descendants
paraphyletic group
includes an ancestor and some of its descendants (but not all)
polyphyletic group
includes organisms that may show some sort of similarity but share more recent common ancestry with other taxa; this similarity is usually due to convergent evolution, not homology; these groups do not include the common ancestor of the taxa involved
paraphyletic
What kind of group are prokaryotes?
Carl Woese
Who introduced the 3 domain system in 1977?
paraphyletic
What kind of group is protists?
protists
single-celled eukaryotes are collectively referred to as ____ (also includes some colonial and multicellular species)
mixotrophs
combine photosynthesis and heterotrophic nutrition
Excavata, ‘SAR’ clade, Archaeplastida, Unikonta
Name the four ‘Supergroups’ of eukaryotes
B
All protists are: A) unicellular B) eukaryotic C) symbionts D) monophyletic
excavates
What supergroup?
includes the diplomonads, parabasalids and euglenozoans
characterized by:
reduced mitochondria
unique crystalline rod in flagella
‘excavated’ feeding tube
kinetoplastids and euglenids
What are the two subgroups of the excavate euglenozoans
stramenopiles, alveolates, rhizarians
What are the 3 subgroups of SAR?
stramenopiles
What SAR subgroup?
Have 2 flagella
A “hairy” flagellum
a “smooth” flagellum
Has 4 subgroups
diatoms, golden algae, brown algae, oomycetes
What are the 4 subgroups of SAR stramnopiles?
diatoms
unicellular algae with a two-part glass-like wall of silicon dioxide; photosynthetic
golden algae
photosynthetic subgroup of SAR stramenopiles
brown algae
large, complex multicellular structures (“seaweeds”, kelp); photosynthetic
oomycetes
water molds; decomposers/parasites
alveolates
What SAR subgroup?
membrane-bounded sacs, called alveoli under the plasma membrane (function unknown)
has 3 subgroups
dinoflagellates, apicomplexans, ciliates
What are the three subgroups of SAR alveolates?
dinofagellates
What SAR alveolate?
two flagella, and plates of cellulose armor for protection
coral symbionts
cause of harmful “red tides”
brevetoxins
apicomplexians
What SAR alveolate?
almost all are parasitic
have complex organelles at their apical end for entering cells
ciliates
What SAR alveolate?
have cilia on their surface that help them move and feed
many are predators
have large “macronuclei” and smaller “micronuclei”
Can engage in a type of sexual exchange of genes by swapping micronuclei
rhizarians
What SAR subgroup?
mainly amoboid
move and feed by thread-like pseudopodia
Has 3 subgroups
pseudopodia
used in movement and as a tool to capture prey or obtain required nutrition.
radiolarians, foraminiferans, cercozoans
What are the three subgroups of SAR rhizarians?
radiolarians
What SAR rhizarian subgroup?
internal skeletons of silica
radiating pseudopodia capture small microorganisms and cytoplasmically stream them to the center of the cell
foraminiferans
What SAR rhizarian subgroup?
porous multichambered calcium carbonate shells called tests
pseudopodia extend through the pores of test
archaeplastida
What supergroup?
Defining characteristic – photosynthetic due to a cyanobacterial endosymbiont (i.e. chloroplasts)
has 3 subgroups
red algae, green algae, land plants
3 subgroups of archaeplastida
B
Green algae differ from land plants in that many green algae species...
A) are heterotrophs.
B) are unicellular.
C) have alternation of generations.
D) have cell walls containing cellulose.
unikonta
what supergroup?
defining characteristic - DNA evidence
2 subgroups
amoebozoans and opisthokonts
What are the two subgroups of Unikonta?
amoebozoans
what unikonta subgroup?
lobed-shaped pseudopodia
includes slime molds which display very unique life-cycles
Note
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