CHAPTER 4 – REPRODUCTION AND INHERITANCE Inherited characteristics


A person’s traits are controlled by genes from the male parent’s sperm and the female parent’s egg, which join together during sexual reproduction. These are known as inherited characteristics. Examples of inherited characteristics are hair colour, blood type and the ability to roll your tongue.


Inheritance is the study of how genes are passed from parents to their offspring across generations.


Acquired characteristics


Other characteristics are not genetically controlled. Instead, they are learned throughout life. These are known as acquired characteristics. Examples of acquired characteristics are the ability to read, the ability to ride a bicycle and your accent.


? TEST TUBE


4. Where are genes located? 5. What are chromosomes made from?


6. Is the ability to play a musical instrument an inherited characteristic or an acquired characteristic? Explain your answer.


: Fig. 4.8 The ability to ride a bicycle is an acquired characteristic


EXPERIMENTAL INVESTIGATION 4.1


How can we investigate the percentage frequency of traits for inherited characteristics?


Equipment Pen


Method


1. In pairs, collect the following data for both partners: a. Handedness: left-handed or right-handed?


b. Arm-fold preference: left arm on top or right arm on top?


c. Ear lobe: attached or detached?


2. Compare your data to that of your partner. 3. As a class, compile the data.


4. Use the following formula to calculate the percentage frequency of each trait and record the values:


percentage frequency = number of people with trait total number of people


× 100 j Go to page 6 of your Experimental Investigations Log to write up this investigation.


d. Freckles: freckles or no freckles? e. Hair: curly or straight? f. Chin: cleft or no cleft?


Paper


: Fig. 4.7 The ability to roll your tongue is an inherited characteristic


Elements of Science 33


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