Biology 100 #3

The offspring of two different varieties

Genes that produce a feature

Fully expressed (visable)

No noticable effect on the organisms appearance

Identical alleles

Two different allels for the same trait

Hybrids appearence in intermediate between parental varieties

When parents differ in one characteristic, their hybrid offspring resemble one of the parents; not a blend of the two characteristics!

When hybrids reproduce they have two types of reproductive cells: ¹/₂transmitting the dominate characteristic, the other ¹/₂ transmitting the recessive characteristic of the other parent

Dominence & segregation occur independently if there are two or more characteristics

Genetic makeup

Physical (expressed) traits of an organism

A glycogen protien on the surface of the blood cell

• Can take transfusions from type O only!
• Geno Type = ii
• Antigens = A & B

• Can take transfussions from type O & type A
• Geno Type = iAiA; iAii
• Antigen = B

• Can take transfusions from type O & type B
• Geno Type = iBiB; iBii
• Antigen = A

• Can take transfusions from any blood type!
• Geno Type = iAiB
• No antigens!

• Where a single gene affects more than one characteristic
• Ex. Sickle Cell gene, Marfan Syndrome

• When two or more genes affect a single characteristic
• Ex. Skin color

Mask the expression of other genes

Plants that produce both egg & sperm

Animals that produce both egg & sperm

• 1. Individuals not alike (some differances inherited)
• 2. Individuals differ in reproductive sucess
• 3. Individuals chances for reproductive sucess partly dependent on heredity
• 4. Long time favoritism for more fit individuals over less fit individuals

Are those that leave behind the most genes

A group of individuals with potential to interbreed and produce viable offspring

• 1. Genetic Drift
• 2. Gene Flow
• 3. Mutations
• 4. Non-Random Mating
• 5. Natural Selection

• Agent of evolution
• Change in a gene pool of a small population due to chance
• Ex. Following a volcanic eruption

• Agent of evolution
• Gain of loss of different alleles due to movements of individuals
• Isolation reduces gene flow

• Agent of evolution
• Change in an organisms DNA that creates a new allele
• Very slow process

• Agent of evolution
• Ex. Feminine selection

• Agent of evolution
• Most likely to cause change in a gene pool

When a population includes two or more forms of a phenotypic character

A graded change in inherited characheristics over a geographic continuum

Evolution of a new species

• 1. Mutations
• 2. Sexual recombiations (independent assortment & crossing over)

Reduced variation

Prevents mating by the less able

• Temporal Isolation
• Habitat Isolation
• Behavioral Isolation
• Mechanical Isolation
• Gametic Isolation

• Pre-zygotic barrier
• Breed at different seasons, times of day

• Pre-zygotic barrier
• Live in the same areas but not the same places

• Pre-zygotic barrier
• No sexual attraction

• Pre-zygotic barrier
• Sexual parts dont fit

• Pre-zygotic barrier
• Can mate, but no zygote is formed

• Hybrid Inviability
• Hybrid Sterility
• Hybrid Breakdown

Hybrids don't survive

Hybrids are viable & will mature, but cannot reproduce

First generation viable & fertile, but second generation feeble / sterile

• 1. New, different niche
• 2. Reproductive barriers

• Land masses convege , forming Pangea
• Reshaped biological diversity
• Massive extinctions!!

Pangea begins to break apart

• Modern continents begin to take shape
• Cool climate
• Seas receed from coastal lowlands
• Plants begin to die
• Massive extinctions!!
• Geologist find a thin layer of Iridium mixed with clay that corosponds to this date (common to asteroids / meteors)

India crunches into eurasia, beginning the formation of the Himalayan Mountains

Marine algae

Plants appear on land

Fish

Forests

• Massive extinctions!!
• Incects

First dinosaurs

Dinosaurs rule

• Massive extinctions!!
• Dinosaurs go extinct

Radiation of mammals

Humans Appear

Similar structure due to common ancestry

• Similarities due to convergent evolution
• Ex. Coral snake vs king snake

• Amino Acid sequencing
• DNA sequencing
• DNA - DNA hybridization

• Compare amino acid sequences in a protien
• 104 amino acid positions
• Human vs chimp = 100% match

Measures nucleotide sequence of DNA segments

Ex. Wednesday's lab exercise