patterns of heredity chapter the big idea chapter outline in sexual reproduction, genes are passed...
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Patterns of Heredity
CHAPTER
the BIG ideathe BIG idea
CHAPTER OUTLINE
In sexual reproduction, genes are passed from parents to offspring in predictable patterns.
Living things inherit traits in patterns.4.14.1
Patterns of heredity can be predicted.4.24.2
Meiosis is a special form of cell division.4.34.3
VOCABULARY
KEY CONCEPT CHAPTER HOME
4.14.1
SECTION OUTLINESECTION OUTLINE
Living things inherit traits in patterns.
gene
sexual reproduction
heredity
allele
phenotype
genotype
dominant
recessive
Offspring inherit alleles, which are forms of genes, from their parents. Alleles come on chromosome pairs and can be dominant orrecessive.
alleles
a gene
The alleles you have are your genotype; the observable characteristics that come from your genotype are your phenotype.
VOCABULARY
KEY CONCEPT CHAPTER HOME
Patterns of heredity can be predicted.4.24.2
SECTIONOUTLINESECTIONOUTLINE
ratio
Punnett square
B b
B
b
BB Bb
Bb bb
B = black furb = brown fur
Punnett squares show possible outcomes of heredity.
Ratios and percentages can be used with Punnett squares to express the probability of particular outcomes.
percentage
probability
VOCABULARY
KEY CONCEPT CHAPTER HOME
4.34.3
SECTIONOUTLINESECTIONOUTLINE
Meiosis is a special form of cell division.
egg
gamete
sperm
• At the beginning of meiosis I, the parent cell has two copies of each chromosome pair.• During meiosis I, the homologs of the chromosome pair separate; there are two cells, each with two copies of one homolog from each pair.• During meiosis II, the two copies of each homolog separate; each daughter cell has one homolog.
Meiosis I
Meiosis II
fertilization
meiosis
1n
1n
1n
1n
VOCABULARY
KEY CONCEPT CHAPTER HOME
I. Living things inherit traits in patterns.
A. Parents and offspring are similar.
B. Genes are on chromosome pairs.
4.14.1
KEY CONCEPTSUMMARYKEY CONCEPTSUMMARY
Living things inherit traits in patterns.
1. One Example
C. Gregor Mendel made some important discoveries about heredity.
2. Mendel’s Conclusions
gene
sexual reproduction
heredity
allele
phenotype
genotype
dominant
recessive
1. Phenotype and Genotype
D. Alleles interact to produce traits.
2. Dominant and Recessive Alleles
VOCABULARY
KEY CONCEPT CHAPTER HOME
II. Patterns of heredity can be predicted.
B. Ratios and percentages can express the probability of outcomes.
4.24.2
KEY CONCEPTSUMMARYKEY CONCEPTSUMMARY
A. Punnett squares show possible outcomes for inheritance.
Patterns of heredity can be predicted.
ratio
Punnett square
percentage
probability
VOCABULARY
KEY CONCEPT CHAPTER HOME
III. Meiosis is a special form of cell division.
A. Meiosis is necessary for sexual reproduction.
1. Meiosis I
B. Cells divide twice during meiosis.
4.34.3
KEY CONCEPTSUMMARYKEY CONCEPTSUMMARY
Meiosis is a special form of cell division.
2. Meiosis II
egg
gamete
sperm
fertilization
meiosis
C. Meiosis and mitosis differ in some important ways.