r-selected species

High rate of per capita population growth

poor  competitive ability

Grows quickly 

age early, 

devoting much energy to producing  large number of progeny 

Small in size, and individuals do not live long. 

Random matting

TLS Online TPP Program

#Id: 6753

#Unit 8. Inheritance Biology

Lederberg and Tatum’s experiment demonstrated that bacteria undergo genetic exchange.

TLS Online TPP Program

#Id: 6754

#Unit 8. Inheritance Biology

TLS Online TPP Program

#Id: 2046

#Unit 8. Inheritance Biology

Autosomal Recessive Trait

a. Usually appears in both sexes with equal frequency.

b. Tends to skip generations.

c. Affected offspring are usually born to unaffected parents.

d. When both parents are heterozygous, approximately one-fourth of the offspring will be affected.

e. Appears more frequently among the children of consanguineous marriages.

TLS Online TPP Program

#Id: 2047

#Unit 8. Inheritance Biology

Autosomal Dominant Trait

a. Usually appears in both sexes with equal frequency.

b. Both sexes transmit the trait to their offspring.

c. Does not skip generations.

d. Affected offspring must have an affected parent unless they possess a new mutation.

e. When one parent is affected (heterozygous) and the other parent is unaffected, approximately half of the offspring will be affected.

f. Unaffected parents do not transmit the trait.

TLS Online TPP Program

#Id: 2048

#Unit 8. Inheritance Biology

X-Linked Recessive Trait

a. Usually more males than females are affected.

b. Affected sons are usually born to unaffected mothers; thus, the trait skips generations.

c. Approximately half of a carrier (heterozygous) mother’s sons are affected.

d. Never passed from father to son.

e. All daughters of affected fathers are carriers.

TLS Online TPP Program

#Id: 2049

#Unit 8. Inheritance Biology

X-Linked Recessive Trait

a. Usually more males than females are affected.

b. Affected sons are usually born to unaffected mothers; thus, the trait skips generations.

c. Approximately half of a carrier (heterozygous) mother’s sons are affected.

d. Never passed from father to son.

e. All daughters of affected fathers are carriers.