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