Darwin And Evolution (15)
What ship did Charles Darwin travel on in 1831?
HMS Beagle
What are homologous structures?
Body parts with similar structure that show common ancestry
What is a population?
A group of individuals of the same species that interbreed
What is speciation?
The formation of a new species.
What is the Human Genome Project?
An effort started in 1990 to sequence all human DNA.
Who wrote On the Origin of Species in 1859?
Charles Darwin
What are vestigial organs?
Unused structures inherited from ancestors (example: appendix)
What is a gene pool?
All the genes in a population.
What is reproductive isolation?
When populations cannot interbreed and produce fertile offspring.
Which DNA fragments move farther in gel electrophoresis and why?
Smaller fragments move farther because they pass through pores more easily.
What does “survival of the fittest” mean?
Organisms best adapted to their environment survive and reproduce.
What did Darwin observe on the Galápagos Islands that supported evolution?
Finches, tortoises, and iguanas showed variation adapted to environments.
What is relative frequency?
How often an allele appears in a population.
What is geographic isolation?
Separation by physical barriers like rivers or mountains.
What causes Down syndrome?
Nondisjunction resulting in trisomy 21.
Name the 5 main points of natural selection.
Overproduction, variation exists, variation is inherited, competition, best adapted survive & reproduce
What is comparative embryology?
Study of embryos to show evolutionary relationships.
What are two main sources of genetic variation?
Mutation and genetic reshuffling
What is directional selection?
When one extreme phenotype is favored.
What is sickle cell anemia?
A disorder caused by one amino acid change in hemoglobin that misshapes red blood cells
How did Darwin’s theory differ from Jean-Baptiste Lamarck’s theory?
Lamarck believed acquired traits were inherited; Darwin believed variation exists before environmental change and populations evolve
What is artificial selection?
Humans selecting traits for breeding (selective breeding).
What does the Hardy-Weinberg principle state?
Allele frequencies remain constant unless evolutionary forces act on the population
Compare stabilizing and disruptive selection.
Stabilizing favors the middle; disruptive favors both extremes.
Why is the X chromosome more important than the Y chromosome?
The X chromosome contains many more genes; the Y has very few.