Chapter 4 Flashcards
Origins of Life
How the first living organism came into being
Phylogenies
Genetic lineages (the evolution of genes in a species/group)
Phylogenetic tree
A family tree of all living organisms based on genetic relationships
How many years ago did the origin of life occur?
3.8 billion years ago
Universal ancestor
The first living organism where all living things are descended (where all organisms came from one single ancestor)
What do we know about the origins of life?
That a single-celled organism made copies of itself and led to the creation of many other species
Darwin
Founded natural selection
Gregor Mendel
Founded particulate inheritance (the idea that physical traits can be passed on to their offspring through genes)
Why did Medel’s and Darwin’s ideas fall out of favor?
Their ideas fell out of favor because both of their theories did not explain evolution entirely (both of their theories did not explain the entire picture)
Lamarckian inheritance
The idea that physical traits acquired over one’s lifetime can be passed on to their offspring (cutting hair or an injury)
What don’t we know about evolution?
We don’t know exactly how the first being came to be
Pangenesis
Darwin combined Lamarck’s theory and claimed that the physical traits acquired over one’s lifetime can be passed on through particles sent by all cells of the human body. These particles congregate in the reproductive system. (Incorrect theory)
How was Lamarck’s theory debunked?
It was debunked through an experiment. Weismann cut off mouse tails to see if the cut-off tails would be passed on. However, all of the baby mice were born with intact tails, so Lamarck’s theory was incorrect.
Hugo Marie de Wries
Dutch botanists who created the concept of genes and mutation
Carl Correns
German botanist who discovered the principles of heredity (this was achieved simultaneously but separately from Hugo de Vries)
Mutationists
Group of scientists who believed variation is caused by mutations in distinct inherited cells
Biometricians
A group of scientists believed that individual mutations could not account for a continuous spectrum of variation (the idea that mutations could cause a wide spectrum of variation like height or weight)
Does evolution take place in populations or individuals?
Populations
Population
Group of individuals who are of the same species who are geographically near each other which allows them to reproduce offspring
Species
Organisms of the same group can reproduce with each other because they are biologically and behaviorally compatible to produce with each other
Viable Offpsring
Offspring that are healthy enough to survive to adulthood
William Castle and John Phillips
They discovered that they could breed rats with a wide variety of colors
Thomas Hunt
Conducted studies on fruit flies where he discovered how chromosomes and genes play a role in heredity.
What did Thomas Hunt discover?
Most mutations increased variations within populations rather than creating new species