exam 1 Flashcards
phylogeny
the evolutionary history of a species or group of species
systematics
the study of classification used to construct phylogenies
taxonomy
the science of naming and classifying organisms
binomial nomenclature
every organism has a unique Latin genus and species name
specific epithet
the species name that differentiates organisms in the same genus
hierarchical classification
Domain>Kingdom>Phylum>Class>Order>Family>Genus>Species
taxon
any level within hierarchical classification
linking classification and phylogeny
systematists depict evolutionary relationships in branching phylogenetic trees
phylogenic tree
a branching diagram that represents evolutionary relationships between species
branch points
represents the divergence of two species
sister taxa
groups that share an immediate common ancestor
root
includes a branch to represent the last common ancestor of all taxa in the tree
polytomy
a branch from which more than two groups emerge
what we can/can’t learn from phylogenetic trees
-patterns of descent
-do not indicate when species evolved or how much genetic change has occurred
-shouldnt be assumed that a taxon evolved from the one next to it
morphological and molecular homologies
organisms with similar morphologies (DNA sequences) are likely to be more closely related
homology
similarity due to shared ancestry
analogy
similarity due to convergent evolution
cladistics
groupings of organisms by common descent
clades
a group of species that includes an ancestral species and all its descendants
monophyletic
a clade containing an ancestor species and all its descendants
paraphyletic
contains ancestor, but not all of its descendants
polyphyletic
a group of species with no common ancestor
from two kingdoms to 3 domains
used to classify all organisms as plants or animals, now there are 3 domains: Bacteria, Archaea, Eukarya
sizes and shapes of common bacteria
spherical-cocci
rod-shaped-bacilli
spiral
cell surface structures
cell walls used for protection and prevention of bursting in hypotonic environment
peptidoglycan
a network of sugar polymers cross-linked by polypeptides in bacterial cell walls
Gram stain
procedure of detecting bacteria species based on cell wall
Gram-positive
darker stain, cocci (spherical)- simple walls with thick layer of peptidoglycan
Gram-negative
lighter stained rods- more structurally complex
capsule
a dense and well defined layer outside prokaryote cells that is a sticky layer of protein
fimbriae
hairlike appendages that prokaryotes use to stick to substrate or each other
pili
longer and less numerous fimbriae used to pull two cells together to transfer DNA
motility
means of transportation of a cell
bacterial flagellum
helical filamentous organelle used for motility
taxis
internal and genomic organization
prokaryotic cells usually lack complex compartmentalization
prok. genome has less DNA than euk. genome
prokaryotic genome
circular chromosome
nucleoid
irregular shaped region in prok. cell where most genetic material is stored
plasmid
smaller rings of DNA found in some bacteria species
prok. reproduction and adaptation
quick reproduction by binary fission and can divide every 1-3 hours
endospores
highly retractive thick walled structures formed in bacteria that can remain viable in harsh conditions for centuries
rapid reproduction and mutation
mutation rates are low, yet since reproduction is rapid, mutations can accumulate quickly in a population
prok. genetic diversity factors
-rapid reproduction
-mutation
-genetic recombination
genetic recombination
through transformation, transduction, and conjugation
transformation
prok. cell can take up and incorporate foreign DNA from surrounding environment
transduction
the movement of genes between bacteria and bacteriophages ( viruses that infect bacteria)
conjugation
where genetic material is transferred between bacteria cells
nutritional and metabolic types of bacteria
photoautotrophs, chemoautotrophs, photoheterotroph, chemoheterotroph
role of bacteria in chemical cycling
major role in recycling between living and nonliving components of ecosystem
-chemoheterotrophic prok. function as decomposers
-nitrogen fixation
nitrogen fixation
some prok. can convert atmospheric nitrogen (N2) to ammonia (NH3)
metabolic cooperation
the exchange of molecules among cells through permeable junctions formed at sites of cell contact
obligate anaerobes
poisoned by oxygen and use fermentation or anaerobic resp
obligate aerobes
require oxygen for cellular resp
facultative anaerobes
can survive with or without oxygen
biofilm
surface-coating colonies where metabolic cooperation occurs
roles of prokaryotes on biosphere
vital role- produce genetic diversity, fix most of our components of the atmosphere, play part in vital cycle
chemical recycling
breaking down corpses, dead vegetation, and waste products
decomposer
break down dead organisms and create new usable compounds
symbiosis
a close, long term relationship between organisms
mutualism
both organisms benefit from relationship
commensalism
one benefits, other is unaffected
parasite
one benefits, another is harmed
pathogen
a microorganism that causes disease
harmful and beneficial effects of bacteria on humans
some bacteria is beneficial, others are pathogens
exotoxin
cause disease even if the prokaryotes that produced it are not present
endotoxin
are released only when bacteria die and cell wall breaks down
protist
informal name of the kingdom of mostly unicellular eukaryotes
unicellularity
most protists are unicellular, yet some are colonial and multicellular
structural and functional diversity of protists
protists have more structure and functional diversity than any other group of eukaryotes due to their biological functions being carried out by individual organelles
mixotroph
combine photosynthesis and heterotrophic nutrition
endosymbiosis in eukaryotic evolution
theory that organelles originated by one organism living inside another, eventually losing its walls and evolving to become one organism
secondary endosymbiosis
the evolution of one cell who has already underwent primary symbiosis enters another cell to evolve further
5 supergroups of eukaryotes
Excavata, SAR, archaeplastida, unikonta
SAR clade
controversial: SAR is believed to be monophyletic and originated by a secondary endosymbiosis event with red alga
-stramenopiles, Alveolates, rhizarians
Excavata
characterized by cytoskeleton and may have feeding groove
-includes diplomonads, parabasalids, euglenozoans
Stramenopiles
most have a “hairy” flagellum paired with a “smooth” flagellum
chromAlveolata
developed as a result of secondary endosymbiosis event. contain alveoli structure
Rhizaria
threadlike and needlelike pseudopodia
Archaeplastida
red algae, green algae, and land plants
Unikonta
animals, fungi, and some protists, broken into two groups: amoebozoans, and opisthokonts (animals fungi etc.)
euglenozoans
within Excavata: a spiral or crystalline rod of unknown inside their flagella.
-kinetoplastids and euglenids
kinetoplastids
within eugelenozoa: have a single mitochondrion with an organized mass of DNA called a kinetoplast
trypanosome
a kinetoplastid that causes sleeping sickness in humans
euglenids
within euglenozoan: have 1 or 2 flagella that emerge from a pocket at one end of the cell
Alveolates
membrane bound sacs (alveolata) just under plasma membrane with unknown function
-includes dinoflagellates, apicomplexans, and ciliates
dinoflagellates
within Alveolates: diverse aquatic plankton. 2 flagella make them spin in the water, cause of toxic red tides
apicomplexans
within Alveolates: parasites of animals and disease causing. contain non-photosynthetic plastid called the apicoplast. specialized apex for penetrating a host
plasmodium life cycle
a species of apicomplexan, causes malaria, requires both humans and mosquitos to complete life cycle
malaria
deadly disease with ongoing vaccine efforts to target this pathogen
apicoplast
non-photosynthetic plastid in apicomplexans
ciliates
within Alveolates: possess both large micronuclei and small micronuclei (used in conjugation-a sexual process that produces genetic variation)
diatoms
in stramenopile: unicellular algae with unique two-part glass like wall of hydrated silica.
golden algae
in stramenopile: yellow and brown carotenoids give golden color, cells are biflagellate with both on one end, unicellular but also colonial
brown algae
in stramenopile: largest and most complex algae, multicellular, includes many “seaweed” species
thallus
full body of the algal seaweed
holdfast
anchors into substrate
stipe
stem of seaweed
blades
leaflike ends of seaweed
red algae
within archaeplastida: contains red pigments to absorb light at lower depths
green algae
within archaeplastida: green color comes from chlorophyll
DHFR-TS gene fusion
amoebazoans
amoeba that have lobe or tube shaped psuedopodia (rather than threadlike)
opisthokonts
roles of protists in ecological relationship
symbiotic protists
photosynthetic protists
plant evolution and diversity
evidence for land plants evolving from green algae
a heterotrophic protist had a Cyanobacteria endosymbiont. green algae contains same pigments as land plants unlike other algae
rosette complexes
peroxisome enzymes
structure of flagellated sperm
formation of phragmoplast
adaptations enabling the move to land
sporopllenin
