Jonathan Olson Unit 1 18 March 2014
1.1 Evolution and Life on Earth
How all organisms are the same
o Composed of one or more cells
o Uses energy
o Has metabolism
o Responds to stimuli
o Supposedly all cells have DNA, but I don’t think that red blood cells do
• Cell membrane
o Unifies all organisms
o Made of the same building blocks, has the same shape (even though sometimes it is circular, sometimes
it is in chromosomal xs), act the same way, and very commonly twists in the same direction.
o Is horizontal gene transfer not considered evolution?
o The first step was the recognition of diversity
o Formally called taxonomy
o Aristotle was classified as the father of taxonomy, creating the “Ladder of Life”, in which he placed
animals according to the function and complexity. Most complex (humans) were at the top.
o He believed that a species (a group or organisms that looked and behaved alike), could never
This is the Doctrine of Fixed Species
Carl Linnaeus introduced Binomial Nomenclature, not Aristotle
o Linnaeus published the final edition of his classification system (Systema Naturae) in 1758
o Both Aristotle’s and Linnaeus’ classification techniques focused more on visual, phenotypic
characteristics, rather than on DNA sequence (as they didn’t know of DNA specifically), or on
o Systematics – The newer model of classification, first developed by Charles Darwin, organizes
the diversity of life according to natural, evolutionary relationships through time.
o Darwin receives much acclaim for the progression of the Theory of Natural Selection, because of
his writing On the Origin of Species
o As I said earlier, Darwin also did not know specifically of DNA
o Darwin was one of many to speculate on inheritance, but when he was in the Galapagos, he
found many fossils of birds, showing the possible ancestors of those he saw live. Their beaks and
bone structures varied, guiding him to believe that the birds passed down something to their
offspring, which can eventually offer great variation between distant relatives.
o Darwin noticed that some organisms were better fit to survive and reproduce, thus passing on
their genome more than those that cannot survive as easily to pass on their genome.
Competition for limited resources
“Struggle for Existence”
o Gregor Mendel was researching the inheritance patterns of peas, leading his to his idea of
discrete particles being passed from parent to offspring, leading to the phenotype. [Type text] [Type text] [Type text]
o Speciation – the process by which new species derive
o Microevolution – the change in frequency of an allele in a population
o Macroevolution – the actual growth to speciation of a population, in which, over time, the
frequency of alleles in a population change so much, that speciation occurs.
o Macroevolution relies on the same mechanisms as microevolution, but generally, requires a
physical barrier to separate two populations.
o Land barriers are not always needed, such as in the event of polyploidy, so that polyploidic
organisms can no longer breed with diploidic organisms, of the same “species”. (But no longer of
the same species, according to the Biological Model of speciation, in which a “species” is a
group of organisms that can reproduce fertile offspring.
Evolution: The Core Theme In Biology
o Darwin said “descent with modification”, instead of “evolution”
o Extinction occurs when a species cannot adapt to a changed environment
o Mutation rates in organisms can be used to help determine when speciation occurred
o Natural selection acts on individuals
o The consequences of natural selection are felt at the population level
o Competition leads to increased prevalence of adaptations
1.2 Energy and Matter
o Energy – the capacity to do work or cause change
o Cells of all organisms use Adenosine Triphosphate (ATP)
o Organic molecules – compounds that contain carbon atoms, although some such compounds – such as
carbon dioxide –