biology 1108 exam 1

exam one

Evolution (LO1)

A change in allele frequency in a population over time.

Population (LO1)

A group of individuals of the same species.

Alleles (LO1)

Variants of genes.

Adaptations (LO1)

Heritable traits that help individuals survive and reproduce in their current environment.

Natural selection (LO1)

Increases the frequency of the advantageous traits in the population over time; a mechanism of evolution.

Fitness (LO1)

An individual’s ability to survive and reproduce.

Stabilizing selection (LO1)

Favors survival of individuals with intermediate phenotypes.

Directional selection (LO1)

Favors individuals at one extreme of a phenotypic range.

Disruptive selection (LO1)

Two or more extreme phenotypes are favored.

Genetic drift (LO1)

Changes in allele frequency due to random chance events, such as bottlenecks or founder effects.

Gene flow (LO1)

Involves the movement of genes into or out of a population.

Mutation (LO1)

Creation of new alleles; the original source of all genetic variation.

Speciation (LO2)

The formation of 2 species from an ancestral species.

Biological species concept (LO3)

A species is one whose organisms can actually or potentially reproduce viable fertile offspring.

Morphological species concept (LO3)

A species defined by members having similar morphology (physical structure).

Phylogenetic species concept (LO3)

A species is the smallest tip on a phylogenetic tree, indicating common ancestry.

Reproductively isolated species (LO1.)

Organisms that can breed within their own group but not outside of it.

Prezygotic mechanisms (LO1.0)

Mechanisms that prevent the formation of a zygote.

Postzygotic isolating mechanisms (LO1.0)

Mechanisms where a zygote is formed but may not develop properly or may be sterile.

Allopatric speciation (LO3.0)

Reproductive isolation due to a geographic barrier.

Dispersal (LO3.0)

When individuals colonize a new habitat that is geographically isolated.

Vicariance (LO3.0)

A physical barrier forms that separates populations.

Sympatric speciation (LO3.0)

Populations become reproductively isolated without physical separation.

Polyploidy (LO3.0)

Having more than 2 sets of chromosomes.

Autopolyploidy (LO3.0)

Diploid plant reproduces diploid gametes due to an error in meiosis.

Allopolyploidy (LO3.0)

Chromosomal changes resulting when gametes from 2 different species combine to form a hybrid.

Phylogeny (LO4.1)

The evolutionary history and relationships of a group of organisms.

Phylogenetic trees (LO4.1)

Diagrams used to depict evolutionary history and relationships.

Monophyletic group (clade) (LO4.1)

A group including a common ancestor and all descendants of that ancestor.

Paraphyletic group (LO4.1)

A group that includes a common ancestor and some descendants.

Synapomorphies (LO4.1)

Shared derived characters of monophyletic groups.

Homologous traits (LO4.1)

Traits similar due to common ancestry.

Analogous traits (LO4.1)

Traits that are similar but were not inherited from a common ancestor.

Convergent evolution (LO4.1)

Independent evolution leading to similar features.

Maximum parsimony (LO4.1)

Grouping taxa in ways that minimize the number of evolutionary changes.

Sister groups (LO4.1)

Descendants that split from the same node; closest relatives to each other.

Outgroup (LO4.1)

A taxon outside the groups of interest, often used to help construct a phylogeny.

Taxonomy (LO5.1)

The science of classifying organisms.

Binomial nomenclature (LO5.1)

The two-word convention of naming species (Genus species).

Domain (LO5.2)

The broadest taxonomic group, including Bacteria, Archaea, and Eukarya.

Bacteria (LO5.2)

Prokaryotes; cells that lack a membrane-bound nucleus, have little to no organelles, reproduce via binary fission, and have a peptidoglycan cell wall.

Archaea (LO5.2)

Prokaryotes; distinct cell membrane chemistry, no peptidoglycan, reproduce via binary fission, and can live in extreme environments.

Eukarya (LO5.2)

Eukaryotes; contain a membrane-bound nucleus, internal organelles, can be multicellular, and reproduce by mitosis and cytokinesis.

Adaptive Radiation (LO5.4)

The rapid speciation of an ancestral lineage into many descendants adapted to diverse niches.

Niche (LO5.4)

A species’ role within the environment (space it occupies, resources used, behavior, etc.).

Mass Extinction (LO5.5)

Events that wipe out most species within a relatively short period; five mass extinctions have occurred in the past 500 million years.

Age of the Earth (LO5.3)

~4.6 billion years

Appearance of prokaryotic fossils (LO5.3)

~3.5-3.8 billion years

Prokaryotes (LO6.1)

Oldest, structurally simplest, and most abundant forms of life; 90 to 99% are unknown and undescribed; less than 1% cause disease; fall into two domains: Bacteria and Archaea.

Tracing the Lineages (LO6.1)

The ancestor to modern archaea is believed to have given rise to Eukarya.

Binary Fission (LO6.1)

The process where genomic DNA is replicated and divided, along with the cytoplasmic contents, resulting in 2 identical daughter cells.

Plasma Membrane (LO6.1)

Bacterial lipids are unbranched and use ester bonds; archaeal membranes are formed on a glycerol skeleton with ether linkages; hydrocarbons may be branched or have rings; tetraether polymer allows extremophiles to withstand high temperatures

Glycocalyces (LO6.1)

Gelatinous sticky substance surrounding outside of the cell, composed of polysaccharides, polypeptides, or both.

Glycocalyces Capsule (LO6.1)

Structured layer composed of organized repeating units of organic chemicals, firmly attached to the cell surface, may prevent bacteria from being recognized by the host.

Glycocalyces Slime layer (LO6.1)

Loosely attached, water-soluble, sticky layer that allows prokaryotes to attach to surfaces.

S-layer (surface layer) (LO6.1)

Rigid protein or glycoprotein layer found in some bacteria and archaea, providing protection, structural support, and adhesion.

Flagella (LO6.1)

Slender, rigid helical structures composed of the protein flagellin, involved in locomotion, spinning like a propeller.

Pilus (pili) (LO6.1)

Short, hairlike structures found in gram-negative bacteria that aid in attachment and conjugation.

Prokaryotic morphology (LO6.1)

The shapes of prokaryotes: cocci (spherical), bacilli (rod), spirilla (spiral).

Endospores (LO6.1)

Thick walls that develop around the genome and a small portion of the cytoplasm, highly resistant to environmental stress.

Symbiosis (LO6.1)

Ecological relationship between different species that live in direct contact with each other.

Mutualism (LO6.1)

Type of symbiosis where both parties benefit.

Commensalism (LO6.1)

Type of symbiosis where one organism benefits and the other is unaffected.

Parasitism (LO6.1)

Type of symbiosis where one organism benefits and the other is harmed.

Bacterial Cell Walls (LO6.2)

Provide structure, shape, protect the cell from osmotic forces, and assist in attachment and resistance to antibiotics.

Peptidoglycan (LO6.2)

Forms a rigid network in bacterial cell walls, maintains shape and withstands hypotonic environments.

Gram stain (LO6.2)

Stains bacteria purple or pink based on cell wall characteristics.

Gram-positive (LO6.2)

Bacteria with a thicker peptidoglycan wall that stain purple.

Gram-negative (LO6.2)

Bacteria that contain less peptidoglycan, stain pink, and have a bilayer membrane that often impedes disease treatment.

Extremophiles (LO6.3)

Organisms that thrive in extreme environments, such as oceans, hot springs, polar regions, deserts, and more.

Halobacteria (LO6.3)

salt-loving bacteria

Microbial Nutrient Utilization (LO7.1)

Organisms use a variety of nutrients for energy needs and to build organic molecules and cellular structures; most common nutrients contain necessary elements (C, O, N, H).

Autotrophs (LO7.1)

Organisms that obtain carbon from inorganic sources.

Heterotrophs (LO7.1)

Organisms that obtain carbon from organic sources.

Chemotrophs (LO7.1)

Organisms that obtain energy from chemical compounds.

Phototrophs (LO7.1)

Organisms that obtain energy from sunlight.

Horizontal Gene Transfer (LO7.2)

The transfer of genetic material between prokaryotes that allows for genetic variation despite asexual reproduction.

Griffith’s Bacterial Transformation Experiment (LO7.2)

Experiment by Frederick Griffith in the late 1920s that studied virulence in Streptococcus pneumoniae.

Lederberg and Tatum’s Work with E. coli (LO7.2)

Demonstrated genetic transfer between bacterial strains of E. coli with different nutritional requirements.

Bernard Davis’s U-tube Experiment (LO7.2)

Showed that direct cell-to-cell contact is necessary for bacterial conjugation.

Transformation (LO7.2)

The process where a bacterial cell takes up DNA directly from the environment, which may remain as plasmids or integrate into the host genome.

Transduction (LO7.2)

The process by which a bacteriophage injects DNA into a bacterium, incorporating genetic material from another prokaryote.

Conjugation (LO7.2)

The transfer of DNA from one bacterial cell to another through a pilus.

Natural Transformation (LO7.2)

Occurs when bacteria take up foreign DNA from their environment.

Artificial Transformation (LO7.2)

Laboratory methods used to introduce foreign DNA into bacteria.

Antoni van Leeuwenhoek (LO7.3)

Pioneer of microbiology who created simple microscopes to visualize microscopic life, calling them 'animalcules'.

Louis Pasteur’s Swan-Neck Flask Experiment (LO7.3)

Experiment that disproved spontaneous generation of microbial life by showing that no growth occurred in sterile conditions.

Robert Koch (LO7.3)

Studied anthrax and proposed Koch’s Postulates to establish a causal relationship between a microorganism and disease.

Koch’s Postulates (LO7.3)

Criteria to identify the causative agent of disease: must be present in diseased organisms, isolated and grown, cause disease in healthy hosts, and be re-isolated.

Pathogens (LO7.4)

Microbes that cause disease symptoms in host organisms.

Beneficial Prokaryotes (LO7.4)

A small percentage of bacteria that are not pathogenic and play vital roles in ecosystems, such as in nutrient cycles.

Element Fixation (LO7.4)

The process of converting elements from the environment into forms usable by living organisms.

Biofactories (LO7.4)

Microorganisms engineered to produce various chemicals, including insulin and antibiotics.

Bioremediation (LO7.4)

The use of microbes to remove pollutants from the environment, such as in the Exxon Valdez oil spill.

Biostimulation/Bioenhancement (LO7.4)

The addition of nutrients to encourage the growth of naturally occurring microbes.

Primary endosymbiosis (LO8.1)

The process in which a host eukaryotic cell engulfs a cyanobacterium, leading to a symbiotic relationship where the bacterium loses independent function and its genetic material transfers to the nuclear genome, evolving into an organelle.

Secondary endosymbiosis (LO8.1)

The process where a protist engulfs another prokaryotic cell that has already undergone primary endosymbiosis, resulting in the engulfed cell losing its original structure and transferring its genes to the host's nuclear genome.

Evidence of primary endosymbiosis (LO8.1)

Includes DNA found in mitochondria and chloroplasts, organelles with double membranes, highly folded inner membranes, and the presence of ETC and ATP synthase.

Evidence of secondary endosymbiosis (LO8.1)

Some plastids have 3 membranes instead of the usual 4, as seen in organisms like brown algae, diatoms, euglena, and dinoflagellates.

Morphological forms (LO8.2)

Different structural forms of protists, which can be unicellular, colonial, filamentous, or multicellular.