CHAPTER  8 Heredity KSEEB SSLC CLASS 10 SCIENCE SOLUTIONS

CHAPTER  8 Heredity KSEEB SSLC CLASS 10 SCIENCE SOLUTIONS

 

CHAPTER  8 Heredity KSEEB SSLC CLASS 10 SCIENCE SOLUTIONS English medium Karnataka state board,the Answers Are Prepared By Our Teachers Which Are Simple ,Pointwise,Easy To Read And Remember

 

CHAPTER  8 Heredity KSEEB SSLC CLASS 10 SCIENCE SOLUTIONS

1. If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
– Trait B is likely to have arisen earlier.
– Reason: A trait found in a higher percentage of the population has had more time to spread and accumulate.
– In this case, 60% indicates more widespread occurrence compared to 10%.

2. How does the creation of variations in a species promote survival?
– Different advantages: Variations provide different advantages to individuals in changing environments.
– Environmental adaptation: Variations help some individuals adapt better to environmental changes (e.g., bacteria surviving heat).
– Natural selection: Variations that provide survival advantages are selected by nature.
– Evolution: This process leads to the evolution of species over time.
– Example: Heat-resistant bacteria surviving a heat wave illustrates the advantage of beneficial variations.

 

  1. How do Mendel’s experiments show that traits may be dominant or recessive?
    • Mendel’s experiments with pea plants illustrate dominant and recessive traits.
    • Dominant traits are expressed when at least one gene copy is present, masking recessive traits.
    • For instance, tallness (T) was dominant over shortness (t) in Mendel’s pea plants.

 

  1. How do Mendel’s experiments show that traits are inherited independently?
  • Mendel’s pea plant experiments demonstrate independent inheritance of traits.
  • Traits such as plant height and seed shape are inherited independently.
  • This is evident in the F2 generation where new trait combinations appear.

 

  1. A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?
  • Information about blood group inheritance isn’t enough to determine dominance.
  • Blood group inheritance is complex with multiple alleles.
  • The daughter having blood group O could inherit two O alleles or one A and one O allele.

 

  1. How is the sex of the child determined in human beings?
  • In humans, sex determination relies on sex chromosomes.
  • Females have two X chromosomes (XX), males have one X and one Y chromosome (XY).
  • The presence of a Y chromosome determines male development, while absence leads to female development.
  • The child’s sex is determined by what they inherit from their father, as mothers always pass on an X chromosome.
EXERCISES
  1. A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggests that the genetic make-up of the tall parent can be depicted as

(a) TTWW

(b) TTww

(c) TtWW

(d) TtWw

Answer;- (c) TtWW

Reasone :-For the Mendelian experiment with tall pea plants bearing violet flowers crossed with short pea plants bearing white flowers:

  • The progeny all bore violet flowers, indicating dominance of the violet flower trait.
  • Almost half of the progeny were short, suggesting the segregation of the short trait.
  • This suggests that the genetic make-up of the tall parent can be depicted as:

 

2.A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not?

Regarding the study on children with light-colored eyes:

  • It indicates that children with light-colored eyes are likely to have parents with light-colored eyes due to the inheritance of traits.

Based on this, we cannot conclusively determine whether the light eye color trait is dominant or recessive without further breeding experiments or genetic analysis

3.Outline a project which aims to find the dominant coat colour in dogs.

Outline of a project to find the dominant coat color in dogs:

  • Collect data on coat colors of parent dogs and their offspring, ensuring a large sample size for statistical significance.
  • Analyze the frequency of coat colors among offspring to identify any patterns or trends.
  • Utilize genetic analysis techniques to determine the inheritance pattern of coat color traits.
  • Perform breeding experiments to test the dominance of certain coat colors and observe the phenotypic ratios among offspring.
  • Draw conclusions regarding the dominant coat color trait based on the observed data and analysis.

 

4.How is the equal genetic contribution of male and female parents ensured in the progeny?

Ensuring equal genetic contribution of male and female parents in progeny:

  • Each parent contributes one set of chromosomes to offspring during sexual reproduction.
  • Fusion of male and female gametes ensures equal genetic contribution.
  • Meiosis produces gametes with half the chromosome number, ensuring diversity.
  • Random assortment and crossing over during meiosis increase genetic variation.
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