Evolutionary Biology Practice Flashcards

A comprehensive set of 300 vocabulary flashcards covering key concepts from Evolutionary Biology Chapters 1-5, including HIV evolution, evidence for evolution, natural selection mechanisms, phylogenetic estimation, and genetic variation.

Active site

The region of an enzyme where a substrate binds and a chemical reaction occurs.

AIDS

Acquired immune deficiency syndrome, the advanced stage of HIV infection in which immune function has severely declined.

Antiretroviral drug

A medication that interferes with the reproduction of a retrovirus such as HIV.

Assembly

The stage when viral RNA and proteins come together to form a new virus particle.

Attachment

The first stage of HIV infection, when viral proteins bind to CD4 and a coreceptor.

AZT

Azidothymidine, a thymidine-like reverse transcriptase inhibitor that terminates viral DNA synthesis.

Budding

Exit of a new virus from the host cell while taking part of the host membrane as its envelope.

Bushmeat

Wild animals hunted for food; handling infected primates may have helped SIV enter humans.

CCR5

A coreceptor on immune cells that many HIV-$1$ strains use with CD4 to enter the cell.

CCR5-Delta32

A $32$-base-pair deletion in CCR5 that can provide strong resistance to CCR5-dependent HIV when homozygous.

CD4 receptor

A surface protein on helper T cells and some other immune cells that HIV binds during infection.

CD4 T-cell count

The number of CD4 helper T cells in the blood, used to monitor immune-system damage.

Chain termination

Stopping DNA growth because the next nucleotide cannot be added.

Coreceptor

An additional cell-surface receptor HIV uses after binding CD4.

Coreceptor inhibitor

A drug that blocks HIV from using a coreceptor such as CCR5.

Drug resistance

The ability of a virus to survive and reproduce despite exposure to a drug.

Entry or fusion inhibitor

A drug that prevents HIV from entering or fusing with a host cell.

Evolutionary medicine

The application of evolutionary principles to health, disease, pathogens, and treatment.

Fusion

Joining of the HIV envelope with the host-cell membrane.

Group M

The major HIV-$1$ group responsible for about $95$\text{ percent} of global infections.

Group N

A rare HIV-$1$ group found mainly in Cameroon.

Group O

An outlier HIV-$1$ group concentrated in West-Central Africa.

Group P

An extremely rare HIV-$1$ group associated with gorilla-related ancestry.

HAART

Highly active antiretroviral therapy, a combination of more than $2$ drugs that attack different parts of the HIV life cycle.

Helper T cell

A CD4-positive immune cell that coordinates other parts of the immune response.

HIV

Human immunodeficiency virus, the retrovirus that attacks key immune cells and can cause AIDS.

HIV-1

The most widespread and generally more virulent type of HIV.

HIV-2

A less virulent and less transmissible type found mainly in West Africa.

Host

The organism or cell used by a parasite or virus for survival and reproduction.

Integrase

The HIV enzyme that inserts viral DNA into the host genome.

Integrase inhibitor

A drug that blocks insertion of HIV DNA into host DNA.

Integration

Insertion of viral DNA into the host cell's DNA.

Lethality

The ability of a disease to cause death.

Macrophage

An immune cell that engulfs pathogens and can be infected by HIV.

Maturation

The final step in which protease cuts viral precursor proteins, producing an infectious virion.

Microevolution

Small-scale evolutionary change within a population, such as drug resistance evolving inside one patient.

Obligate intracellular parasite

A virus or organism that can reproduce only inside a living host cell.

Opportunistic infection

An infection that becomes dangerous when the immune system is weakened.

Phylogeny

A hypothesis of evolutionary relationships among organisms or viral lineages.

Precursor protein

A long viral protein that must be cut into smaller functional proteins.

Protease

The HIV enzyme that cleaves precursor proteins during maturation.

Protease inhibitor

A drug that blocks viral maturation by inhibiting protease.

Provirus

Viral DNA that has been integrated into the host genome.

Reverse transcriptase

The error-prone HIV enzyme that copies viral RNA into DNA.

Reverse transcriptase inhibitor

A drug that blocks reverse transcriptase or imitates DNA building blocks.

Reverse transcription

The production of DNA from an RNA template.

Selection pressure

An environmental factor that causes some heritable variants to reproduce more successfully than others.

SIV

Simian immunodeficiency virus, a group of primate viruses closely related to HIV.

Transcription

Production of RNA from a DNA template.

Translation

Use of RNA instructions by ribosomes to produce proteins.

Transmission rate hypothesis

The hypothesis that frequent transmission can favor greater virulence, while limited transmission can favor lower virulence.

Uncoating

Release of viral RNA and enzymes from the viral capsid inside the host cell.

Viral load

The amount of HIV present in a person's blood.

Virion

A complete virus particle capable of infecting a host cell.

Virulence

The severity or harmfulness of a disease or pathogen.

Absolute dating

Determining a numerical age, usually in years.

Ambulocetus

An early whale relative with both terrestrial and aquatic adaptations.

Analogous structure

A structure with a similar function or appearance that evolved independently.

Archaeopteryx

A transitional fossil with bird-like feathers and dinosaur-like skeletal traits.

Artificial selection

Human-directed breeding in which individuals with desired inherited traits are chosen to reproduce.

Biogeography

The study of the geographic distribution of living and fossil organisms.

Catastrophism

The idea that Earth's major features were formed mainly by sudden catastrophic events.

Codon

A three-nucleotide sequence that specifies an amino acid or stop signal.

Common ancestry

The principle that different organisms share ancestors in their evolutionary history.

Continental drift

The movement of continents over geological time.

Convergent evolution

Independent evolution of similar traits in unrelated lineages exposed to similar selection pressures.

Daughter isotope

The product formed by radioactive decay.

Descent with modification

Darwin's phrase for inheritance from ancestors combined with evolutionary change over time.

Developmental homology

Similarity in developmental processes caused by common ancestry.

Epigenetics

Persistent or heritable changes in gene activity that occur without changing the DNA sequence.

Evolution

Change in inherited characteristics of populations over generations.

Extinction

The permanent disappearance of a species or lineage.

Fossil

Preserved evidence of an organism that lived in the past.

Fossil biogeography

The study of the geographic distribution of fossils.

Fossil record

The total collection and chronological pattern of fossils in rock layers.

Genetic homology

Similarity in genes or DNA sequences caused by common ancestry.

Geological time scale

A chronological framework dividing Earth's history into intervals based on rocks and fossils.

Half-life

The time required for half of a radioactive parent isotope to decay.

Homologous structure

A structure inherited from a common ancestor that may perform different functions in descendants.

Homology

Similarity caused by common ancestry.

Homoplasy

Similarity that did not arise from common ancestry.

Immutable

Unable to change.

Inheritance of acquired characteristics

Lamarck's idea that changes acquired during life are passed to offspring.

Intron

A noncoding section removed from an RNA transcript before translation.

Isotope

A version of an element that differs in neutron number.

Law of succession

The observation that fossils in a region resemble living species from that region.

Natural selection

The process in which individuals with favorable heritable traits leave more offspring.

Parent isotope

The original unstable radioactive isotope.

Plate tectonics

The theory that Earth's outer surface is divided into moving plates.

Processed pseudogene

A nonfunctional gene copy produced when processed mRNA is reverse transcribed and inserted into the genome.

Promoter

A DNA region involved in starting transcription.

Pseudogene

A gene-like DNA sequence that has lost normal function.

Radioactive decay

The spontaneous conversion of an unstable isotope into another isotope.

Radiometric dating

A method that determines rock ages using radioactive isotopes.

Relative dating

Determining whether one rock or fossil is older or younger than another without assigning an exact age.

Seafloor spreading

Formation and outward movement of new oceanic crust at mid-ocean ridges.

Selective breeding

Another term for artificial selection.

Special creation

The historical belief that species were independently created, immutable, and placed on a young Earth.

Speciation

The evolutionary formation of new species.

Structural homology

Similarity in anatomy caused by common ancestry.