Systematics
Classifies organisms and determines their evolutionary relationships. Use fossil,molecular and genetic data to infer relationships.
Phylogeny
Evolutionary history of a species or group of related species
Taxonomy
Ordered division and naming of organisms
Binomial nomenclature
Two parts for naming a species, called binomial. First part is called genus, second part called specific epithet, first part capitalized and the entire name is it italicized.
Hierarchical classification
Broad to narrow, domain, kingdom, phylum, class, order, family, genus, species
Taxon
A unit at any level of hierarchy
Phylogenetic tree
Represents a hypothesis about evolutionary relationships. Branch point shows divergence of two species and a sister taxa are groups that share a common ancestor.
Homologies
Phenotypic and genetic similarities due to shared ancestry, example: is the four limbs of tetrapods.
Analogy
Similar because of convergent evolution, example: the wings of bats, birds, and insects evolved independently from each other but all are used to perform the function of flying.
Outgroup
Species that is closely related to the ingroup, it is a group that has diverged before the ingroup.
Ingroup
The various species being studied. This and outgroup are used to study to see the difference between shared derived and shared ancestral characteristics.
Clade
a group of organisms believed to have evolved from a common ancestor
Five kingdoms
Prokaryotes, protists, plants, fungi and animalia
Three domains
Bacteria, archaea and eukarya
Eukaryotes are closely related to Archaea than to bacteria
Eukarya have plants, animals, fungi. Archaea have halophiles, thermophiles. Bacteria have cyanobacteria, plastids that have chloroplasts.
Prokaryotes are divided to two domains, archaea and bacteria.
Live anywhere, acidic, hot, cold, are microscopic, very small but their is alot of them.
Prokaryotic cells, are unicellular so it only has one cell, they are very small.
Have three shapes, spheres, rods and spirals.
Bacteria cell walls have peptidoglycan.
Sugar polymers cross linked with polypeptides
Gram stain classifies bacteria cell wall composition.
Gram(+): have simpler walls with a large amount of peptidoglycan. Gram(-): have less peptidoglycan and an outer membrane that can be toxic.
Antibiotics target peptidoglycan and damage bacterial cell walls.
Gram(-) is more likely to be antibiotic resistant.
Archaea has polysaccharides and proteins, no peptidoglycan.
A protein layer is called a capsule and covers many prokaryotes.
Fimbriae
Allows prokaryotes to stick on their substance or other individuals.
Bacteria exhibit taxis. Chemotaxis is the movement toward or away a chemical stimulus.
Taxis is the ability to move toward or away a stimulus.A stimulus is anything that can trigger behavior.
Prokaryotes, have endospores.
They remain successful in harsh conditions. Thats why prokaryotes can live anywhere.
Phototrophs
Obtain energy from light
Chemotrophs
Obtain energy from chemicals
Autrotrophs- photoautotroph and chemoautotroph
Require CO2 as carbon source. Photo- need light and CO2.
Chemi- need inorganic chemicals for energy and CO2 for carbon source.
Heterotrophs- photoheterotrophs and chemoheterotrophs
Require an organic nutrient to make organic compounds.
Photo- need light and organic compounds.
Chemo- need organic compounds for energy and carbon source
Obligate aerobes
Need O2 for respiration
Obligate anaerobes
Are poisoned by O2 and use anaerobic respiration.
Faculative anaerobes
Can survive with or without oxygen
Nitrogen fixation
Some prokaryotes convert atmospheric nitrogen (N2) to ammonia (NH3)
Metabolic cooperation
Prokaryotes use environmental resources because they cant do it by themselves. Ex: photosynthetic cells and nitrogen fixing cells called heterocysts exchanged metabolic products.
Biofilms
Metabolic cooperation occurs in this surface coating colony
Molecular systematics
Led to splitting of prokaryotes into bacteria and archaea, and continue to work on the phylogeny of prokaryotes
Archaea live in extreme environments called extremophiles
Halophiles- live in saline environments
Thermophiles- live in hot environments
Methanogens
Live in swamps, produce methane and are poisoned by oxygen making them anaerobes.
Chemical recycling
Chemoheterotroph prokaryotes are decomposers and break down dead organisms and waste products
Symbiosis
Relationship in which two species live in close contact. Larger called host and smaller called symbiont. Do this with larger organisms.
Mutualism
Both organisms benefit
Commensalism
One organism benefits and the other is not harmed or helped
Paratism
An organism is a parasite and harms but doesn’t kill the host. Parasites that cause disease are pathogens.
Mutualistic bacteria
Human intestines are home to 500-1000 species of bacteria and break down food
Exotins
Cause disease even if the prokaryote isn’t present
Endontoxins
Released only when the bacteria die and their cell walls break down.