Midterm Flashcards
clade
a group of organisms that have descended from a common ancestor
Homologous
Describes characters that are similar in different species because of descent from a common ancestor; the noun form of homology
Analogous
Describes similar characters that evolved independently in different groups resulting from similar selection pressures
Synapomorphy
A shared derived character; the basis of phylogenetic reconstruction
Monophyletic
A group containing all known descendants of a common ancestor
Paraphyletic
A group containing a common ancestor but not all of the descendants
Polyphyletic
A group of organisms that does not include the common ancestor
Plasmid
Mobile extra-chromosomal genetic element
Peptidoglycan
Polymer of sugars and amino acids, making up the bacterial cell wall
Binary Fission
Division of one cell into two, more or less equally
Horizontal Gene Transfer
Passing on of genetic material to members of the general community, rather than parent to daughter cell
Anoxygenic
Without the liberation of oxygen
Oxygenic
A reaction that liberates oxygen
Chemotroph
Metabolize inorganic chemicals to generate energy
Phototroph
Producing complex organic molecules by capturing solar energy to make simple organic molecules
Saprophyte
Consuming dead organisms
Phycobilisomes
Structure on the thylakoid membrane organizing accessory pigments
Akinete
Thick-walled, resting cell of cyanobacteria filled with food resources
Heterocyst
Specialized cyanobacteria cell lacking chlorophyll, and producing nitrogenase; fixes Nitrogen and thus must be anaerobic
Stromatolites
Large, dome-shaped structures formed by colonies of cyanobacteria
Supergroup
Taxon used to organize eukaryote phyla. Level of organization between Domain and Phylum
Cristi
Mitochondrial inner membrane; the site of membrane-bound reactions
Undulipodium
Eukaryotic cilia and flagella; NOT bacterial flagella
Dikaryotic
A cell stage immediately after fusion of two haploid cells; following plasmogamy but prior to karyogamy
Plasmogamy
Cell fusion
Karyogamy
Nuclear fusion
Endosymbiosis
The process of one cell moving into another cell and living alongside it, without being destroyed. Over long periods of time, the endosymbiont may lose the ability to survive on it’s own and become dependent of the host cell
Order of taxonomic ranks
Domain
Supergroup
Phylum
Class
Order
Family
Genus
Oxygen on earth
-little or no oxygen for the first 2 billion years
-more oxygen became available (about 1%-10% of todays oxygen)
-oxygen levels finally increased about 580 million years ago and animal fossils also are present at this time
earths atmosphere
-primary atmosphere of H2 and He quickly lost
-secondary atmosphere of reducing gases from volcanic gases (anaerobes and chemotrophs dominated)
-photosynthetic cyanobacteria evolved and O2 slowly increased
-about 2 billion years ago the atmosphere became oxygenating and aerobes became dominant
morphological species concept
-what looks different is different
-developed pre darwin
Biological species concept
-reproductive isolation
-shared derived traits rather than relative difference
-populations and not unconnected individuals
Phylogenetic species concept
-share a combination of derived traits
-species are monophyletic groups that contain all of the known descendants of a single common ancestor and hence share an evolutionary history
-populations must have been evolutionarily independent long enough for diagnostic traits to appear
synapomorphy vs plesiomorphy
Synapomorphy: shared derived characteristic
Plesiomorphy: primitive character
bacterial cells
-single circular chromosome
-additional dna as plasmids
-cell wall made of peptidoglycan
-flagella for locomotion but not the same as in eukaryotes
-asexual reproduction by binary fission
-“sexual” reproduction by conjugation (swap genes) through pilus
proteobacteria
-most diverse bacteria
-key to how C, N, and S move in environment
-ecological relationships with eukaryotes (beneficial and harmful)
-some bad pathogens
myxobacteria
-type of proteobacteria
-cells aggregate to form fruiting bodies
-fruiting bodies form myxospores enclosed in a walled structure (cyst) and are very resistant
-always haploid
gram staining bacteria
Gram Positive:
-purple
-lack outer membrane
Gram Negative:
-red
-have an outer membrane
actinomycetes bacteria
-filamentous gram positive bacteria
-form “fungal” mycelium like masses of filaments
-spores are produced on sometimes-elaborated branching structures
Archaea Vs Bacteria Vs Eukarya
Ribosome Size: 70S, 70S, 80S
Membrane lipid linkages: ether, ester, ester
methanogenesis: yes, no, no
Sensitive to certain antibiotics: no, yes, no
Nitrogen fixation: yes, yes, no
characteristics of archaea
-unique membrane lipids
-no peptidoglycan or chitin in cell wall
-RNA polymerase and ribosomes more similar to eukaryotes
-antibiotics that work on bacteria have no affect indicating difference in translation
producers
-autotrophs
Chemotrophs:
-some bacteria and archaea
-metabolize inorganic chemicals to generate energy for other chemical reactions
Phototrophs:
-produce complex organic molecules by capturing solar energy and use it to make simple organic molecules
consumers
-consume other organisms for their own metabolic processes
-some heterotrophs form symbiotic relationships with autotrophs
-most are herbivores
-some are predators which consume herbivores or other carnivores
-some are omnivores which eat consumers and producers
decomposers
-break down complex organic matter
-saprophytes consume dead organisms and organic matter
-parasites do not wait for organism to die
metabolism in prokaryotes
Bacteria:
-often producers or decomposers
Archaeans:
-often anaerobes
-often producers but not oxygenic phototrophs
-important decomposers especially in man made habitats such as water treatment
metabolisms
Energy source:
-chemo –> chemical reactions
-photo –> electromagnetic radiation (photons)
Electron donor:
-litho –> inorganic chemicals
-organo –> organic chemicals
Carbon source:
-auto –> inorganic carbon
-hetero –> organic carbon
what are microbial mats
-low lying tropical coastlines, carpets of deep blue green cover
-bacteria and archaea able to grow where animals/seaweed cannot
-densely packed communities that differ by depth
pigments in microbial mats
Blue Green:
-on top
-cyanobacteria
-oxygenic, photosynthetic
-well lit, oxygen rich surface
Purple:
-middle
-purple bacteria
-anoxygenic photosynthetic
-light but no oxygen
Black:
-subsurface
-anaerobic respiration and fermentation
how do pigment molecules absorb light
-chemical structure differences allow different wavelength of light to be absorbed
-pigment molecules complex with proteins in membranes of the cell to form photosystems
-two photosystems work in series in oxygenic photosynthesis to harvest enough energy to pull electrons from H2O and subsequently produce ATP
-a single photosystem occurs in anoxygenic photosynthesis and these bacteria use electron donors more easily oxidized
info about cyanobacteria
-blue green algae
-chlorophyll a
-accessory pigments: Carotenoids (orange), phycocyanin (blue green), phycoerythrin (red)
-pigments can be organized along thylakoid membrane as phycobilisomes
-cyanophyte starch
-no flagella
-cellulose and pectin in cell wall; often within sheath
-mostly fresh water
what is Chroococcales
-unicellular and colonial prokaryotic algae
Filamentous Algae
-cyanobacteria
-form filaments of multiple individuals
-individual cells may specialize
-akinete may form which is a thick walled cell filled with food resources
-heterocyst may form which is an anaerobic cell that makes usable N and it lacks chlorophyll to prevent formation of oxygen (nitrogenase cannot function in presence of oxygen)
what are the 5 eukaryote supergroups
- Opisthokonta
- amoebozoa
- archaeplastida
- S.A.R.
- Excavata
Ploidy in eukaryotic cells
Diploid: 2n
-through meiosis (reduction division) reaches haploid
Haploid: 1n
-through cell fusion (plasmogamy) reaches dikaryotic
Dikaryotic: 1n + 1n
-through nuclear fusion (karyogamy) reached haploid
alternation of generations basics
-Diploid sporophyte
-Haploid gametophyte
Genes lost in chloroplast due to endosymbyosis
- genes once needed for the free living cyanobacteria
- genes similar to nuclear genes (redundancy)
- genes migrated to the nucleus of host cell
what is a nucleomorph
-remnant nucleus of engulfed eukaryote
-proof of endosymbiotic theory
evidence of endosymbiotic theory
- chloroplast DNA
- Chlorophyll
- Membranes
- Nucleomorph
supergroup amebozoa
-several phyla of amoebae
-several phyla of slime moulds
-all include at least one life stage by amoeboid movement
-feed by phagocytosis
-most lack flagella
-mitochondria have branching tubular cristae
-mitosis may differ from metamitosis
amoeboid cells
-cells with flexible cell shape
-moving using cytoplasmic extensions (pseudopodia)
-not all cells producing pseudopodia are amoebozoa
-predators
-feed by surrounding prey
-cause amoeba caused diarrhea
-may be naked or testate
naked amoebas
-no hard exterior covering
-pelomyxa (giant free living multi nucleate herbivorous amoeba that lacks most organelles)
testate amoebas
-surrounded by hard shell (test)
-may produce their test or collect foreign particles
-produced tests may be organic (protein), siliceous, or calcareous
cell division in amoebas
-promitosis
-mesomitosis
-metamitosis
promitosis
-nuclear membrane and nucleolus remain intact
-most similar to binary fission
-chromosomes are not clear
mesomitosis
-nucleolus disintegrates
-nuclear membrane persists into anaphase
-no centrioles
-spindle fibers terminate on the nuclear membrane
metamitosis
-more typical mitosis
-membrane loss
-spindle fibers
-still no centrioles but spindle fibers converge to points
-recognizable chromosomes
myxostelida
-plasmodial slime mold
-enormous single cell with thousands of nuclei
-giant cell can move in search of food
-produces fruiting bodies that disperse individual spores
myxostelida life cycle
Diploid:
zygote –> (mitosis) –> feeding plasmodium –> mature plasmodium (preparing to fruit) –> young sporangium –> mature sporangium
Haploid:
spores (formed by meiosis from sporangium) –> germinating spores –> amoeboid cell or flagellated cell –> forms zygote through syngamy
cellular slime mold
-spend most of life as free living individual amoeboid protists
-when in bad conditions cells mass together and form a sporangium which produces spores that form microcysts
-microcysts release amoeboid cells which can fuse (plasmogamy + karyogamy) to form a macrocyst (diploid) in which meiosis occurs
cellular slime mold life cycle
Diploid:
-zygote –> undergoes meiosis and becomes haploid
Haploid:
-amoebas –> aggregated amoebas –> migrating colony –> fruiting bodies –> spores (microcysts) –> emerging amoeba –> solitary cell –> aggregated amoebas –> syngamy to form diploid zygote of necessary
supergroup excavata
-structural feeding groove
-flagellated organisms
-now considered paraphyletic
-simplified mitochondria or lack them completely
-among most primitive protists
-include many anaerobes, endocommensals and parasites
jakobea class
-in supergroup excavata
-small heterotrophs
-found in soil, freshwater, and marine
-aerobic or anaerobic
-not pathogenic
-primitive mitochondrial genome
phylum metamonada
-in supergroup excavata
-anaerobic
-amitochondriate
-may contain hydrogenosomes or mitosomes
-flagella present in group of 4 and associated with nucleus
-diplomonads have 2 sets of nuclei/ flagella groups
parabasalia (metamonad)
-endosymbiotic/endocommensal
-lack feeding groove (secondary loss)
-includes the most common STI in north america
phylum Euglenozoa
-heterotrophs but some have chloroplasts from secondary endosymbiosis (green algae) and are facultative autotrophs
-have chlorophyll a and b and carotenoids
-paramylon is the storage product
-1 tinsel type apical flagellum and a short secondary flagellum
-no cell wall but have a pellicle
-mostly fresh water
movement in euglenids
-contracting and extending the cell
-metaboly
cell division in euglenids
-duplicate organelles
-split from apical end backwards
-nuclear membrane persists through division
-primitive form of cell division
-promitosis
subphylum kinetoplastida
-heterotrophic
-feed on bacteria unless parasitic
-no chloroplasts
-internal parasites of vertebrates
-prominent flagella
-kinetoplast is a DNA containing organelle within the mitochondria
-most common non viral STI
Symapomorphies of archaeplastida
-cellulose cell wall
-lack centrioles
-chloroplast surrounded by 2 membranes
-starch as storage molecule
-mitochondria have flat cristae
phylum glaucophyta
-green unicellular algae
-freshwater ponds/lakes
-plastids = cyanelles
-peptidoglycan wall
-chlorophyll a and phycobilins (no phycoerythrin)
-cyanelles retain more features of ancestral cyanobacteria endosymbiont than any other algae
phylum phodophyta
-red algae
-primary capture of chloroplast
-chlorophyll a, d, phycoerythrin, phycocyanin, and allophycocyanin
-floridean starch
-no flagella
-cellulose, pectin, agar, and carrageenan
-mostly marine
heteromorphic
-sporophyte looks distinct from gametophyte
isomorphic
-sporophyte looks identical to gametophyte
life cycle of pyropia (red algae)
Diphasic
Diploid
fertilization leads to carposporangium –> carpospore –> carposporothallus –> undergoes meiosis
Haploid
meiospores –> immature gametothallus –> gametothallus –> spermatium or carpogonium –> fertilization
life cycle of polysiphonia
-Triphasic
-mixed isomorphic and heteromorphic
-dioecious
Diploid
carposporothallus –> carpospore –> tetrasporothallus –> tetrasporangium –>meiosis
Haploid
Tetraspores (meiospores) –> female or male gametothallus (isomorphic) –> carpogonium or antheridium which produce spermatia –> fertilization –> pericarp (1n) and carposporothallus (2n) (heteromorphic stage)
corallina (red algae)
-macroscopic branching filamentous thallus
-grows on coral reefs
-calcifies
lithothamnion (red algae)
-crustose thalli
-calcified
-grow at bottom of light column or undersea caves
chondrus (red algae)
-irish moss
-source of agar and carrageenan
palmaria (red algae)
-dulse
-macroscopic deeply lobed sheet
-can be eaten
viridiplantae clade
-green algae and land plants
-cellulose in call wall
-chlorophyll a and b
-lack phycobilins
major clades in archaeplastids
-chlorophyta
-charophyta
-embryophyta (land plants)
-streptophytes (may include plants and green algae but excludes chlorophytes
green algae to plants
-one line of green algae gave rise to plantae (land plants)
-paraphyletic if excluded
phylum chlorophyta
-green algae
-chlorophyll a and b and carotenoids
-primary chloroplast
-starch
-2 or 4 apical whiplash type flagella
-cellulose and pectin in cell wall
-mostly fresh water
class chlorophyceae
-phylum chlorophyta
-mixed group
-order volvocales
-order chlorococcales
-order chaetophorales
life cycle of chlamydomonas
-vegetative haploid cells
-forms haploid gametes (+/-), both flagellated
-isogamy
-not flagellated zygote
-dormant stage in soil
-meiosis releases four flagellated haploid cells
life cycle of volvox
-cell on outside of colony undergo multiple mitotic divisions
-form invagination, first with the flagella on the inside and they need to flip
-eventually break out of mother colony
-dominant haploid gametothallus stage
-egg not formed by meiosis; vegetative outer cells are haploid
-sperm with 2 flagella swim to fertilize egg
-diploid zygote as a resting stage over winter
-zygote undergoes meiosis to form new colonies
-zygote is the only cell of the 2n sporothallus stage
class ulvophyceae
-macroscopic marine algae
-order ulvales
-order clasophorales
-order dasycladales
-order caulerpales
siphonocladous
-multicellular with multiple nuclei
siphonous macronucleate
-giant cell with one nucleus
-incomplete mitotic division
siphonous
-giant cell with multiple nuclei
-incomplete mitotic division
life cycle of ulva (sea lettuce)
-isomorphic
Diploid
-zygote –> grows through mitosis into lettuce like sporothallus –> undergoes meiosis
Haploid
-spores –> grow through mitosis into lettuce like gametothallus –> haploid gametes fuse
life cycle of codium
-dominant gametophyte stage
-meiosis forms a haploid, multinucleate, siphonous pseudoparenchymatous gametothallus
Diploid
-zygote –> young sporothallus –> meiosis
Haploid
adult gametothallus –> utricles –> gametangia –> anisogametes –> fertilization
charophytes
-includes several clades
-none have all the traits to be the direct ancestor of land plants but together they do
life cycle of spirogyra
conjugation
class charophyceae (stoneworts)
-oogamy
-egg in protective layer of cells
-macroscopic branching gametothalli
-zygote is the only cell of the sporothallus stage
life cycle of chara corallina
Diploid
-zygote
Haploid
-meiosis in zygote forms haploid cells –> one cell develops into multicellular algae –> sperm released into water which egg is on plant –> fertilization in oogonium –> zygote formed on plant is released for dispersal
