mendel, pea plants, and inheritance patterns ap biology fall 2010
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Theory of Natural Selection did not fit with prevailing view of inheritance ◦ Blending Blending would produce uniform populations; such populations could not evolveTRANSCRIPT
Mendel, Pea Plants, and Inheritance Patterns
AP BiologyFall 2010
Late 19th century, natural selection suggested that a population could evolve if members show variation in heritable
Variations that improved survival chances would be more common in each generation ◦ In time, population would change or evolve
Theory of Natural Selection did not fit with prevailing view of inheritance ◦ Blending
Blending would produce uniform populations; such populations could not evolve
Many observations did not fit blending ◦ White horse and black horse did not produce gray
ones
Gregor Mendel used experiments in plant breeding and knowledge of mathematics to form his hypotheses
Mendel used the garden peas for his experiments This plant can fertilize itself; true breeding
varieties were available to Mendel Peas can be cross fertilized by human
manipulation of pollen
Self fertilizing: flowers produce both male and female gametes
True breeding: successive generations will be like parents in one or more traits ◦ White flowered parent plants give rise to white flowered
offspring
Mendel hypothesized that clearly observable differences might help him track the trait and identify inheritance patterns and heredity
Genes: units of information about specific traits, each located at a particular locus on a chromosome
Homologous Chromosome: diploid cells have 2 genes (a gene pair) for each trait- each on a homologous chromosome
Mutation: alters a gene’s molecular structure Alleles: are various molecular forms of a
gene for the same trait
◦ Page 171, figure 11.4
True Breeding Lineage: occurs when offspring inherit identical alleles, generation after generation
Hybrid Offspring: what non-identical alleles produce
Homozygous: when both alleles are the same
Heterozygous: when the alleles differ When heterozygous one allele is dominant
(A) and the other allele is recessive (a)
Homozygous dominant: AA Homozygous recessive: aa Heterozygous: Aa Genotype: is the particular alleles an
individual carries Phenotype: is how the genes are
expressed physically (what you observe) P: true breeding parental generation F1: first generation offspring F2: second generation offspring of self
fertilized or intercrossed F1 individuals
Jeopardy