Grade 12 Biology Past Paper PDF - Ethiopian Curriculum 2023

## The Theory of Evolution ### Lamarckism - Developed by French biologist Jean-Baptiste Lamarck. - Claimed that organisms pass on acquired traits to their offspring. - Explained by the inheritance of acquired characters, use and disuse of organs and speciation. - **New Needs:** Organisms have to a...

## The Theory of Evolution ### Lamarckism - Developed by French biologist Jean-Baptiste Lamarck. - Claimed that organisms pass on acquired traits to their offspring. - Explained by the inheritance of acquired characters, use and disuse of organs and speciation. - **New Needs:** Organisms have to adapt to new environmental factors like: - Light - Temperature - Medium - Food - Air - **Use and disuse of organs:** Organisms develop traits to meet new needs: - Greater use of certain organs - Lesser use of others (no use). - **Inheritance of acquired characters:** Acquired characters are passed down to offspring. - **Speciation:** New characters acquired each generation lead to the formation of new species over time. ### Activity 4.5 Debating the origin of life - Students are divided into small groups based on the following theories: - The creationists - The spontaneous generationists - The Eternalists - The Cosmozoans - The Abiogenesists - Each group must prepare a case for their theory of the origin of life. - Each group will present their case in a debate, stating, "This house believes that only (Creationism, for example) can truly account for the origin of life." - The group will have 5 minutes to state their case and then answer questions from the other group members. - The rest of the class will vote on whether the group proposing the theory or the group questioning the theory won the debate. ### Darwinism (Theory of natural selection) - Proposed by Charles Darwin. - Based on observations made on the Galapagos Islands. - The islands were inhabited by various species of finches, each adapted to their specific environment. **Basic postulates of Darwinism:** - **Geometric increase:** Species tend to produce more offspring than can survive. - **Struggle for existence:** There is competition for resources between organisms. - **Variation under nature:** Individuals within a species show variations. **Natural selection:** - Individuals with advantageous traits are more likely to survive and reproduce. These traits are then passed on to their offspring. - Over time, these traits become more prevalent in the population, leading to evolution. ### Activity 4.6 - Small groups are to research evidence supporting Lamarck's theory and critiques against it. ### Activity 4.7 - Small groups are tasked with reading from different books about evidence supporting Darwin's theory and critiques against it. - Discuss the reasons why Darwinism is referred to as "descent with modification". - Explain the evolution of the giraffe according to both Darwinism and Lamarkism. ### Activity 4.8 - Form small groups to discuss Lamarck and Darwin's theories of evolution. - Prepare charts comparing and contrasting their explanations. ### Neo-Darwinism theory - Incorporates genetics into Darwin's theory of evolution. - Explains how gene action drives evolution.