21. Describe the contributions of Malthus and Lamarck to Darwin’s hypothesis for
ID: 178032 • Letter: 2
Question
21. Describe the contributions of Malthus and Lamarck to Darwin’s hypothesis for the mechanism of change in animal form over time. What did they propose and how did it affect Darwin’s thinking?
22. Describe Lamarck’s hypothesis about inheritance of acquired characteristics. What evidence do we have that Lamarck’s hypothesis is incorrect?
23. Compare AND contrast Lamarck’s and Darwin’s hypotheses about change in animal form over time.
24. Consider the different types of evidence Darwin used to formulate his hypothesis. 25. What is the mechanism for organisms changing to match their environment over time (adaptation)?
Explanation / Answer
21. Describe the contributions of Malthus and Lamarck to Darwin’s hypothesis for the mechanism of change in animal form over time. What did they propose and how did it affect Darwin’s thinking?
Malthus' view on population growth is:
Malthus noted that humans were being born faster than people were dying. He reasoned that if the human population wasn't balanced, there would not be enough living space and food for everyone.
According to Lamarck's theory "inheritance of acquired characteristics":
He believed that all organisms have an inborn urge to become more complex and perfect.
As a result, organisms change and acquire features that help them live more successfully in their environment, and then pass the acquired traits to their offspring.
In Darwin’s book the Origin of Specieshe combined his own thoughts with ideas from Malthus and Lamarck.
22. Describe Lamarck’s hypothesis about inheritance of acquired characteristics. What evidence do we have that Lamarck’s hypothesis is incorrect?
According to Lamarck’s hypothesis about inheritance of acquired characteristics; h e believed that all organisms have an inborn urge to become more complex and perfect. As a result, organisms change and acquire features that help them live more successfully in their environment, and then pass the acquired traits to their offspring.
Lamarck's theory on evolution was wrong because organisms pass down traits through predetermined genetic information, not based on environmental adaptations during their lifetime. Lamarck proposed that if an organism used a certain muscle differently, like a giraffe having to consistently reach up higher on a tree for leaves, the offspring would naturally have a longer neck but this does not happen (reference, science).
23. Compare AND contrast Lamarck’s and Darwin’s hypotheses about change in animal form over time.
The dissimilarity between the theory proposed by Lamarck and that of Darwin is the fact that:
What does make a difference is that Darwin proposed a mechanism whereby such changes were effected. Changes in species was due to procreation or breeding. Those species that spawned changes which helped to adapt to the new conditions, survived, while those that didn’t eventually died. Incontrast according to Lamarck's theory species underwent changes in response to changes in their environment. One notable example quoted by him was the case as it might exist with respect to Giraffes. Lamarck contended that as trees began to grow taller, giraffes responded to the change by growing longer necks so that they could continue to feed. His second contention was that this change was permanent for as long as the new environmental conditions continued to apply.
24. The different types of evidence Darwin used to formulate his hypothesis are:
Fossil record
Geologic time scale - Earth in ancient; shows that time existed for organisms to develop from ancestral forms
Vestigial traits - Darwin was the first to describe and interpret these traits, which are common
Evidence that species are related - similar finch species (and other flora and fauna) on different Galapagos islands. Darwin reasoned that they shared a common ancestor.
Structural homologies - Darwin pointed out that if all mammals descended from a common ancestor, and if that ancestor had a limb with the same basic arrangement, then it would be logical to observe that its descendants had a modified form of the same arrangement.
Analogous features
What is the mechanism for organisms changing to match their environment over time (adaptation)?
Adaptation is any heritable characteristic that increases an organism's ability to survive and reproduce in is environment. Thus according to Darwin some traits are better suited to life in their environments than others. Thus, only the stronger/faster survive.
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