What is the first filial generation?
F1 generation - generation after parents
For Mendel, this generation was the heterozygous offspring of homozygous dominant and homozygous recessive parentage.
When does the Mendelian ratio appear and what is it?
When a heterozygous F1 generation is self-pollinated.
F2 generation expresses 3:1 dominant:recessive traits
F2 = grandchildren to parent generation
What is the phenotype?
The physical apperance/expression of a trait. Pink, blue, etc.
What is genotype?
The genetic makeup of a trait that produces a certain phenotype. i.e. Tt individual is heterozygous for being tall
An individual has 2 chromosomes for any trait ... these chromosomes will be homologous, meaning that they code for the same trait and have the same gene loci BUT differ in the alleles that they express
What is an allele?
The unique contribution of each homologous chromosome - A is an allele and a is another allele
The Law of Segregation
Alleles segregate independently to offspring.
i.e. even though each parent has two alleles for a given trait, they contribute only one allele to their offspring - this relates to meiosis
What does inbreeding do?
It increases the number of homozygous individuals but DOES NOT change the frequency of an allele
Incomplete dominance vs. co-dominance
Incomplete dominance - white and red flowers make pink flowers
Co-dominance- Human blood type AB antigens both expressed on blood cell membranes
Law of Independent Assortment
If genes coding for different traits are found on different chromosomes, they do not affect each other during gamete formation
What is they're on the same chromosome? The closer together they are, the more likely they'll stay together...but if they're far apart, crossing-over may separate them
- Independent assortment generates genetic variation.
- A cell has 2 copies of each somatic chromosome- one from mom, one from dad (homologous
- chromosomes). Independent assortment shuffles these chromosomes, and then places only one
- copy of each into the gamete. This way, the gamete may have chromosome 1 from mom,
- chromosome 2 from dad, chromosome 3 from dad, ... etc.
What results in a 9:3:3:1 ratio?
A dihybrid cross - i.e something that is heterozygous (hybid) for TWO traits that are being passed together.
WwGg x WwGg
The resulting PHENOTYPIC
ratio will be 9:3:3:1
- 9- dominant, dominant
- 3- dominant, recessive
- 3- recessive, dominant
- 1- recessive, recessive
The 23rd chromosome is the sex chromosome and establishes a person's gender
When is a gene considered to be sex-linked?
When it appears on the 23rd chromosome pair, the sex chromosomes
Usually, the Y chromosome does not carry sex-linkage
Where is the allele for the sex-linked trait carried and what implications does it have?
On the X chromosome
For men, the trait will always be expressed whether it's dominant or recessive because their Y chromosome does not carry a sex-link allele
For women, expressage of sex-linked traits depends on whether the allele is dominant or recessive
What is the Barr body?
The second X chromosome in somatic cells shrivels up and its genes inactivate
If a female is a carrier for a trait she must...
Be carrying the recessive allele for a sex-linked trait on one of her sex chromosomes
What kind of disease is hemophilia?
Are the X and Y chromosomes homologous to one another?
Is evolution a change in:
a.) an individual’s alleles?
b.) a family’s alleles?
c.) a population’s alleles?
d.) a species’ alleles?
C - A population's alleles or GENE POOL
As long as the frequency of alleles in a gene pool remains constant, evolution has not occured
What is the order of taxonomical classification?
King Philip Comes Over for Good Sex
Within each are subgroups --- should know the subphylum Vertebra
What is Vertebra?
A Subphylum falling under the Phylum Chordata
What is more specific, Vertebra of Chordata?
Vertebra = subphylum
Organisms within the same ___ have similar genetic structures.
What is Mammalia?
What is Chordata?
What are domians?
Bacteria ; Archea ; Eukarya
What is a species?
Organisms that can produce fertile offspring with one another
1. Geographic isolation
2. Habitat isolation
3. Seasonal isolation
4. Mechanical isolation
5. Developmental isolation
6. Behavioral isolation
7. Gametic isolation
- 1. Geographic - separated in space
- 2. Habitat- live in the same region but occupy different habitats
- 3. Seasonal - mate in different seasons
- 4. Mechanical - physically impossible to mate with one another
- 5. Developmental - embryo unable to develop
- 6. Behavioral - different mating rituals
- 7. Gametic - gametes are incompatible
Survival of the fittest
No two species can occupy the same niche indefinitely
The fittest organism can survive to produce progeny and ensure that reproduction continues
- Type I - K strategist : few offspring, parental care, slow to mature, SIGMOIDAL GROWTH CURVE THAT LEVELS OFF AT CARRYING CAPACITY , DENSITY-DEPENDENT factors
- Habitats that do not change very often characterize k strategists
Type III - R strategist : many offspring, mature rapidly, no parental care, found in unpredictable environments affected by DENSITY INDEPENDENT FACTORES (environmental fluctuations)
What is speciation and when does it occur?
The formation of a new species
Occurs when gene flow in a population is cut off
What causes speciation?
Geographic, seasonal, and behavioral isolation --- anything that affects gene flow
What is adaptive radiation?
When several species arise from the same ancestral species
What is an evolutionary bottleneck?
When an allelic shift occurs in the members of the species
A SEVERE reduction in population size (natural disaster)
When two species that have similar ancestry have homologous structures
When two unrelated species develop analogously similar structures
Ana = anew
Distinct forms of a phenotypic trait
What satisfies HW equlibrium?
- 1. Large population
- 2. Mutational equilibrium (backward=forward)
- 3. Immigration or emmigration must not change gene pool
- 4. Random mating
- 5. No selection for the fittest organism
What is genetic drift?
Where an allele in lost in a population because all people carrying that allele die off
Caused by random events, not selective pressures
p^2 + 2pq + q^2 = 1
p + q = 1
- Express frequencies in decimal terms
- p^2 = frequency of the homozygous pp
- 2pq = frequency of the heterozygous pq
- q^2 = frequency of the homozygous qq
- p = frequency of p allele
- q = frequency of q allele
First attempt to recreate the atmosphere of early earth
Lipid/protein bubbles through to be the first cells evolved
Chordata is a phylum
Chordates have bilateral symmetry
Chordates are deuterostomes = anus develops near blastopore
Have coelom, notochors, pharyngeal slits, hollow nerve cord, and a tail
What is a coelom?
A characteristic of chordates : a body cavity with mesodermal tissue
What are the classes of vertebra?
- 1. Agnatha
- 2. Cartilaginous fish
- 3. Bony fish
- 4. Amphibians
- 5. Reptiles
- 6. Birds
- 7. Mammals
Do catastrophic events change HW?
No. Nothing like floods, earthquakes etc change HW
Can migratory birds be of the same species?
Yes, migratory birds aren't geographically isolated
What is mutualism?
When both things depend on each other for survival or equal benefits
i.e. GM Corn cannot survive without human intervention so it benefits from humans just the way that we benefit from eating it
The Molecular Clock Theory
We can find how much time has passed by measuring the amount of neutral mutations
From whom are cellular organelles inherited?
Phenotype is affected by?
Fitness = the ability to pass on traits to offspring.
If an individual is healthy, but cannot reproduce, he/she is not fit. It's all about the ability to reproduce and produce viable offspring!! Predation has nothing to do with it.
Human taxonomical classification
- Domain: Eukarya
- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Primata
- Family: Homididae
- Genus: Homo
- Species: Sapiens