Viral Life Cycles
This term describes the cycle where a virus immediately hijacks a cell to make copies and then bursts it open.
What is the lytic cycle?
This 19th-century scientist is known as the "Father of Evolution" for his work on the Galapagos Islands.
Who is Charles Darwin?
Unlike living cells, viruses lack these tiny "protein factories."
What are ribosomes?
These preserved remains of ancient organisms provide a chronological record of life on Earth.
What are fossils?
On a phylogenetic tree, the "tips" or "leaves" represent these, which are groups of similar organisms that can breed together.
What are species?
In this quieter cycle, viral DNA integrates into the host's genome and remains "hidden" for many generations.
What is the lysogenic cycle?
This is any inherited trait that increases an organism’s chance of surviving and reproducing in its environment.
What is an adaptation?
This fatty outer layer, stolen from the host cell’s membrane, helps some viruses sneak past immune systems.
What is an envelope?
These are body parts that share a similar structure across different species, suggesting a common ancestor.
What are homologous structures?
This is the point on a tree where a branch splits in two, representing a common ancestor "dividing" into new groups.
What is a node?
This viral enzyme is used by retroviruses to turn their RNA "blueprints" into DNA.
What is reverse transcriptase?
This "ship" carried Darwin on his five-year voyage around the world.
What is the HMS Beagle?
These "keys" on the surface of a virus allow it to bind to specific receptors on a host cell.
What are surface proteins (or glycoproteins)?
These "leftover" structures, like the human tailbone, have lost their original function over time.
What are vestigial structures?
If two species are right next to each other on the tree and share the same most recent node, they are called these "siblings."
What are sister groups (or sister taxa)?
This is the specific term for a virus that infects and kills bacteria.
What is a bacteriophage?
This measure of reproductive success determines how well an organism's genes are passed to the next generation.
What is fitness?
Most viruses consist of genetic material surrounded by this protective protein shell.
What is a capsid?
This modern field compares DNA sequences to determine how closely related two species are.
What is molecular biology (or comparative genomics)?
This term refers to an ancient individual that two different species both descended from.
What is a common ancestor?
These small, circular RNA molecules are even simpler than viruses and typically infect plants.
What are viroids?
This type of selection occurs when humans, rather than nature, choose which traits are passed on, such as in dog breeding.
What is artificial selection?
This is the technical term for the complete, infectious form of a virus outside of a host cell.
What is a virion?
This term describes the study of how and why plants and animals live where they do around the world.
What is biogeography?
This is the starting point at the very bottom of the tree that represents the oldest ancestor of every group shown.
What is the root?