Types of Speciation
What is allopatric speciation?
Speciation that occurs when a population is divided by a geographic barrier
An ancestral population and all of its descendents.
What is a virus?
An obligate intracellular parasite that invades a host and hijacks cells for replication
What are the five stages of the viral life cycle?
Attachment, entry, genome replication & expression, assembly, and exit
Phenotypic or genetic similarities due to shared ancestry
Homology
What is sympatric speciation?
Speciation that occurs in populations living in the same geographic area
An ancestral population and some but not all of its descendants
Paraphyletic Group
What is a capsid?
The protein shell that surrounds a virus’s nucleic acid (RNA or DNA)
What is the Lytic cylce?
The cycle in which a phage replicates and causes the host cell to burst (lyse)
What is the principle that states the phylogenetic tree requiring the fewest evolutionary changes is the most likely
Maximum parsimony
The presence of extra chromosome sets due to errors in cell division; common in plants
Distantly related species that do not share an exclusive common ancestor
What is a viral envelope?
The outer layer of some viruses, made of lipids and sometimes glycoproteins, derived from the host cell membrane and surrounds the capsid
What is the Lysogenic cycle?
The cycle in which the phage genome is integrated into the host chromosome and is replicated without destroying the host
What is Cladistics?
The scientific approach that builds evolutionary trees (phylogenies) using shared derived traits of organisms
What is an autopolyploid?
A polyploid individual whose extra chromosomes come from a single ancestral species
What is a basal taxon
The term for the outgroup lineage (diverged early) that does NOT mean “primitive” or “least evolved”
Viruses that infect bacteria and are the best-understood of all viruses
Phages that can only use the lytic cycle
What are the three ways sympatric speciation occur?
polyploidy, sexual selection, and habitat differentiation
What is an allopolyploid?
A fertile polyploid that arises after two different species form a sterile hybrid that later doubles its chromosomes
What is a sister taxon?
Two taxa that share an immediate common ancestor and are each other’s closest relatives
What are the types of Genomes a virus can have (aka Baltimore classes)?
dsDNA, ssDNA, -ssRNA, +ssRNA, dsRNA, Retrovirus (ssRNA), Retrovirus (dsDNA)
What are temperate phages?
Phages that can use either the lytic or lysogenic cycle
Name the three domains of life and state why viruses are generally not considered alive.
Bacteria, Archaea, and Eukarya. Viruses lack cellular structure and cannot independently metabolize or reproduce