INTRO TO EVOLUTION PT. 1 & 2 Flashcards
Define evolution. (3)
- decent with modification
- change over time
- all organisms are related through an unbroken chain of events
Why is evolution both fact and fiction?
fact: there is a genealogical connection between living things
theory: propositions used to explainthe causes of evolutionary change (i.e. darwin’s theory of natural selection)
what year did darwin propose his theory of natural selection?
1859
what ship did Darwin travel on?
HMS Beagle
what were Darwin’s three arguments for Natural Selection?
- living things tend to multiply
- progeny cannot all survive due to resources
- living things vary; some are better equipped
who coined the term ‘survival of the fittest’?
Herbert Spencer
Darwin + Mendel =
Neodarwinism
Neo-Darwinism
Darwinism as modified by the findings of modern genetics
Darwin’s Theory of Pangenesis
‘Blending’ of genes
What Mendel called a ‘heritable factor’ is what we now call a ______.
gene
An organism with two identical alleles for a character is said to be ______ for the gene controlling that character
homozygous
An organism that has two different alleles for a gene is said to be ______ for the gene controlling that character
heterozygous
are heterozygotes or homozygotes true-breeding?
homozygotes
What concept did Mendel work with?
Inheritance
how many pairs of genes are in humans?
22 autosome, 1 sex chromosome
August Weisemann
germ plasm theory, inheritance takes place by means of the germ cells. Somatic cells do not function as agents of heredity
germ cell
gametes (egg or sperm cells)
Somatic cell
non-reproductive cells
mitosis
cell growth
2N > 2N
meiosis
chromosome number halved
2N>1N
what are four causes of gene variations?
- combination
- reassortment
- dominance/supression
- mutation
who revealed an elegant double-helical model for the structure of DNA?
Watson and Crick
what does DNA stand for?
Deoxyribonucleic acid
what traits does DNA pass on?
biochemical, anatomical, physiological and behavioural
Four bits that make up DNA
Adenine, Thymine, Guanine, Cytosine
What pairs with Adenine?
Thymine
what pairs with Guanine?
Cytosine
what is Watson and Crick’s model’s name? what does it mean?
semiconservative model of replication. when the double helix replicates, each daughter molecule will have one old strand and one new strand
DNA replication
DNA>DNA
Transcription
DNA>RNA
what is another name for polypeptide?
protein. many amino acids
what does PCR stand for? what does it mean?
Polymerase Chain Reaction.
can produce many copies of a specific target segment of DNA
what are the three steps of PCR, and what is this process called?
thermo cycling.
- heating
- cooling
- replication
what is the ‘key’ to PCR?
Taq polymerase, a heat-stable dna polymerase.
three things that DNA cloning allow researchers to do:
- compare genes and alleles between individuals
- locate gene expression in a body
- determine the role of a gene in an organism
sister taxa
groups that share an immediate common ancestor
what is a ‘rooted’ phylogenic tree?
includes a branch to represent the last common ancestor of all taxa in the tree
basal taxon
diverges early in the history of a group and originates near the common ancestor of the group
PCR: basic concept
- allows us to sequence DNA
- used to understand relationships and produce phylogenetic hypothesis
Watson and Crick discovered:
DNA
what are three problems associated with Natural Selection?
This theory strips comforts as:
- a guaruntee of progress
- a principle of natural harmony
- any notion of an inherent goal or purpose
