Exam 2 Flashcards
What are systematics?
Reconstruction and study of evolutionary relationships
What is phylogeny?
Hypothesis about relationships among taxonomic groups, depicted as a phylogenetic tree or cladogram.
Think of a family tree.
What are analogous characters (homoplasy)?
Similar due to functional or ecological constraints/pressures.
Characters can be very similar in appearance due to evolutionary convergence.
Convergence occurs in unrelated taxa when characters are shaped by similar ecological or evolutionary constraints.
What is outgroup analysis?
Used to estimate which attributes are shared derived characters in each group of organisms.
Homologous characters?
Similar due to evolutionary origin
Based on genetics and developmental origin
Look similar but not always, same purpose.
What are shared derived characteristics (synapomorphy)?
Arose(derived) within the larger clade, distinguishes those that share it from those who don’t. Provides information about relatedness within the larger group. Used to identify branch points (nodes) within the larger clade.
What is the rule of parsimony?
Choose the simplest cladogram with the fewest steps or events.
Monophyletic group (monophyly)?
Includes all descendants of a given ancestor, includes the most recent common ancestor and all descendants, each clade represents a single cut.
Paraphyletic group?
Contains a common ancestor and some, but not all, of its descendants, shares ancestral characters.
Polyphyletic group?
Consists of several evolutionary lines that do not share the same recent common ancestor, unnatural grouping that misrepresent evolutionary relationships.
Bacteria plasma membrane?
Bacterial lipids are unbranched and use ester bonds.
Archaea plasma membrane?
Archaean membranes are formed on glycerol skeleton with ether linkages.
Bacteria cell wall, DNA replication and gene expression?
Bacteria have peptidoglycan, both have single replication origin
Archaea cell wall, DNA replication and gene expression?
Archaea lack peptidoglycan, archaeal DNA replication is more similar to that of eukaryotes, archaeal transcription and translation are more similar to those of eukaryotes.
What is molecular classification?
Amino acid sequences of key proteins, percent guanine-cytosine content, nucleic acid hybridization, gene and RNA sequencing, whole genome sequencing.
Basic bacterial shapes?
Cocci, bacilli, spirilli
What’s the S layer (prokaryotes)?
Rigid procrystalline layer found in some bacteria and archaea. Outside of peptidoglycan or outer membrane layer in gram neg, and gram pos bacteria. Diverse functions, often involves adhesion.
What’s the capsule (prokaryotes)?
Gelatinous layer found in some bacteria, aids in attachment, protects from immune system.
What is transformation?
Cell takes up prokaryotic DNA directly from environment.
What is transduction?
A bacteriophage injects DNA into the cell that contains small fragment of DNA from a different prokaryote.
What is conjugation?
DNA is transferred from one cell to another via a pilus that connects the 2 cells.
Dental caries (tooth decay)?
Plaque consists of bacterial biofilms, streptococcus sobrinus ferments sugar to lactic acid, tooth enamel degenerates.
Peptic ulcers?
Heliobacter pylori is the main cause. Treated with antibiotics
Autotrophs?
From inorganic CO2
Photoautotrophs?
Energy from sun
Chemolithoautotrophs?
Energy from oxidizing inorganic substances
Heterotrophs?
From organic molecules
Photoheterotrophs?
light as energy source but obtain organic carbon made by other organisms
Chemoheterotroph?
Both carbon atoms and energy from organic molecules
Major groups of prokaryotes?
Endospores form when exposed to environment stress, bacteria cause tetanus, botulism and anthrax.
Prokaryotes Un cellularity
Single-celled, may stick together to form associations and biofilms
Prokaryotes cell size
much smaller than eukaryotes, most are less than 1 mm in diameter
Prokaryotes nucleoid?
Chromosome is single, circular, double-stranded DNA, found in nucleoid region of cell, often have plasmids.
Prokaryotes cell division & genetic recombination.
Most divide by binary fission, exchange genetic material extensively.
Flagella (major group of prokaryotes)?
Slender, rigid, helical structures, composed of the protein flagellin, involved in locomotion - spins like propeller.
Pili (major group of prokaryotes)?
Short, hairlike structures, found in gram negative bacteria, aid in attachment and conjugation.
