Question

.1 Imagine a small fish that lives in a rocky coastal area. The fish is a light color almost white but the rocks in which it hides are dark black and grey. Describe how this population of fish could change to be a darker color (to be more camouflaged in the rocks) through the process of natural selection. Include a list of steps for this fish that would have to take place for natural selection to work.

2. Answer each part listed below • Describe what is meant by “There is unity in the diversity of life” and give an example. • Describe what is meant by an emergent property in life and give and example • Explain how are both ideas supported by and connected via Darwinian evolution ?

3. Describe a controlled experiment that you could set up to demonstrate natural selection in the fish example above (question 1). What would be the hypothesis? List which aspects of the experiment are the control, experimental variable, the independent and the dependent variable.

4. Compare and contrast prokaryotic cells and eukaryotic cells? Can a single cell be a living organism? Explain your answer 5. Draw the basic structure of DNA. Label the parts. How do physical traits such as eye color arise from such a simple structured molecule? In other words, how are genes “expressed” physically? Read the pdf article about Environmental DNA. In three sentences describe the main ideas in the article. 6. Charles Darwin made many observations of organisms all over the world. He noted the differences in similar organisms (finches, tortoises, etc) that lived in different environments. Also, also noted similarities between different organisms that live in similar environments, like large flightless birds that looked like ostriches in south America and Africa that are not related. From these various observations, he concluded that organisms are adapted to the environmental conditions in which they live. Is this an example of inductive or deductive reasoning? Explain you reasoning and use a different example as an analogy.

Answer 1

ANSWER

1. Populations adapt and evolve because of natural selection. The individual organisms who happen to be best suited to a particular environment, do survive and reproduce successfully. In the fish population, individuals that will develop beneficial traits like dark colour, will have better chances of survival as because they will be properly camouflaged among the black and grey rocks. The fishes who cannot blend with the rocks, will be seen and eaten by predators. The greater the variety of traits that exist in a population, the greater is the population's chances of survival. This is how natural selection works.

Natural selection occurs in the following steps:

Step 1 - Reproduction.

For natural selection to act, the fish must reproduce to create new generation. Over the generations, the fishes that will have traits for dark colour will reproduce more than the light coloured fishes. Natural selection in course of time, maximises the number of individuals with favoured traits and those with less favoured traits, perish gradually.

Step 2 - Heredity.

Heredity works in tandem with reproduction. The dark, better camouflaged fishes will pass on their advantageous traits to the next generation for natural selection to act.

Step 3 - Variation in characters.

Variation in colour among the fishes is very essential for natural selection to act. This variation allows nature to select the 'fittest' individuals, who are better camouflaged and evade the predatory eyes.

Step 4 - Variation in Fitness.

In the fish population, some individuals must have traits that favour them to adapt more than others. This allows them to reproduce more frequently and pass on the beneficial traits.