Exam #1 Flashcards
Scientific Law
A generalization about something in nature. The “what”
Scientific Theory
the explanation of a phenomena. the “why”
Evolution
biological change from generation to generation
Uniformitarianism
earth is changed by natural processes operating both today and in the past
Catasrophism
theory that the Earth has been affected in the past by sudden, short-lived, violent events, possibly worldwide in scope. This was in contrast to uniformitarianism, in which slow incremental changes, such as erosion, created all the Earth’s geological features.
Taxonomic Classifications
Kingdom, Phylum, Class, Order, Family, Genus, species
Carolus Linnaeus
(1707) Came up with taxonomic classifications
Lamarck
(1744) Inheritance of acquired characteristics
Inheritance of acquired characteristics
Actions during life cause new traits in the body. These traits are passed onto offspring
Problems with Inheritance of acquired characteristics
Not seen in real life (ear cropping, circumcision), DNA in sperm/egg doesn’t change, could emphasize current traits but not create new ones. Did lead to epigenetics.
Epigenetics
Some behaviors or conditions may influence genes in the next generation
Year that Origin of Species was published
1859
Two discoveries from his travels
Variation in environment = variation in characteristics.
Similar species in different locations have a common ancestor
Thomas Malthus
population growth vs food supply. More are born than can survive.
Equation for natural selection
Variation. Heritability. Selection.
Adaptation
spread because they increase a parent’s fitness
Fitness
average # of offspring from a parent with a given trait
Misconceptions about Evolution
Evolution is a theory about the origin of life. Evolution cannot be measured or tested. Evolution is random. Evolution gives organisms what they need. Evolution results in progress. All traits are adaptations.
Sexual Selection
A trait is appealing to the opposite trait but it may decrease fitness.
Natural Selection
theory for the process of biological change from generation to generation
Gene
discrete physical unit responsible for each trait. Sequence of base pairs on a strand of DNA.
allele
different versions of the same trait
chromosomes
fibers in the nucleus of the cell
prokaryote
single cell bacteria with no internal membrane bound compartments
eukaryote
cells with internal compartments separated by membranes
nucleus
Stores DNA containing majority of genes
mitochondria
produces energy. Has its own DNA with a few genes
Nitrogenous Base
bases on one backbone form a hydrogen bond on another backbone. They are uncharged and face inwards.
Phosphate Group
On backbone. Negatively charged and face outward.
Four Nitrogenous Bases
Adenine, Guainine, Thymine, Cytosine
Complementary Base Pairs
Guainine + Cytosine
Thymine + Adenine
DNA Replication
occur’s in a cell’s nucleus. uses base-pair rule to make a copy of itself so the cell can divide.
Four Steps of Replication
- Helicase breaks hydrogen bonds to separate strands. 2. DNA primase adds a shorter primer 3. Free-floating nucleotides added by DNA polymerase III 4. Lagging strand is copied in the opposite direction in pieces which are later joined in one strand
RNA
Ribonucleic Acid. Used to copy DNA.
Transcription
Gene to mRNA. DNA strand separates near the gene. Complementary mRNA bases attach to make mRNA. Thymine turns into Uracil. (A now pairs with U)
Transfer RNA
tRNA matches the correct amino acid to each codon on the mRNA.
Translation
mRNA to protein. mRNA to protein
Intron
doesn’t code but may be responsible for turning genes on and off
Exon
coding portion of DNA. Codes for a specific protein
mtDNA
mitochondrial DNA. contains only 37 genes vs 2,000 in DNA. Passed down through mother’s lineage.
Diploid
has full chromosome number
homologous chromosomes
a pair of chromosomes coming from the mother and father that carry the same genes
homozygous
both alleles are the same
heterozygous
alleles are different
Somatic Cells
non-sex cells. 22 pairs
Mitosis
Somatic cell division. Starting cell has 46 chromosomes and produces two daughter cells with 46 chromosomes each.
Gamete
Sexual reproduction cell
zygote
offspring
haploid
only half the full number of chromosomes
Meiosis
creates gametes. 4 unique haploids
crossing over
for a given gene, the maternal and paternal version of a chromosome switch alleles.
genotype
the two alleles that an individual has for a given gene
Phenotype
the physical expression of a given gene
homozygous dominant
both alleles are dominant
homozygous recessive
both alleles are recessive
Mendel’s Law of Segregation
A parent will contribute only one of its two alleles for its given locus to the gamete. Segregation is due to the pairs of maternal and paternal chromosomes separating during Meiosis I
Mendel’s Law of Independent Assortment
different traits are inherited independently of each other. ex: coat color and tail length are inherited separately
ratio of independent traits
9:3:3:1
Polygenic Traits
phenotypic traits influenced by two or more genes. May be influenced by the environment. Continuous variation
Mendelian Traits
phenotypic traits produced by a single gene, not influenced by the environment. discontinuous variation
Antigens
proteins on the surface of cells that tell your body the cells belong to you. ABO blood types
AB blood type
co-dominant
high heritability
trait expression is largely controlled by genes. more susceptible to natural selection
low heritability
trait largely controlled by environment. Less susceptible to natural selection
