![]() exponential progression), while food resources only increase arithmetically (i.e. The Malthusian dilemma was proposed by English clergyman Thomas Malthus who identified that populations multiply geometrically (i.e. For plants, cacti have water storage tissue and spines (prevent water loss) because of the infrequent rainfall in the desert. They have hollow fur to aid in insulation as well. They are strong swimmers, aided by their strong forearms and layer of blubber for buoyancy. ![]() They have a large layer of blubber to keep them warm. Polar bears are well adapted to life in the Arctic.In other words their structure allows them to function in that environment.Where and how an organism lives is largely due to its specific adaptations that allow it to survive and reproduce in a particular area or habitat.The product of natural selection is the adaptation of populations of organisms to their environment.Natural selection occurs through an interaction between the environment and the variability inherent among the individual organisms making up a population.Developmental: Variable changes that occur across the life span of an organism (e.g.Biochemical: Differences in molecular composition of cells and enzyme functions (e.g.Physiological: Variations in detection and response by vital organs (e.g.Behavioural: Differences in patterns of activity (e.g.Structural: Physical differences in biological structure (e.g.Evolution – Over time, there is a change in allele frequency within the population gene poolĪdaptations are features of organisms that aid their survival by allowing them to be better suited to their environment adaptations may be classified in a number of different ways:.Adaptations – Individuals with beneficial traits will be more likely to survive and pass these traits on to their offspring.Selection – Environmental pressures lead to differential reproduction within a population.Competition – There is a struggle for survival (species tend to produce more offspring than the environment can support).Inherited Variation – There is genetic variation within a population which can be inherited.The process of natural selection occurs in response to a number of conditions: If there was no variation within a species, then all individuals would be the same and no individual would be favoured over the other and natural selection would not take place. Individuals that are best suited for their environment will survive and reproduce. Within a species, different individuals of that species show genetic variation. According to this theory, it is not necessarily the strongest or most intelligent that survives, but the ones most responsive to change. There was a change in the color of the landscape.ī.The theory of natural selection was posited by Charles Darwin (and also Alfred Wallace) who described it as ‘survival of the fittest’. What environmental change gave a selective advantage for oneĪ. Light substrate than there were light mice on the dark coloredĢ. Dark fur because there were many more dark furred mice on the ![]() The dark substrate than there were dark mice on the light coloredĭ. Light fur because there were many more light furred mice on Light fur because more of the mice in both types of habitatĬ. Dark fur because more of the mice in both types of habitatī. ![]() We consider comparative overall fitness for the entire area, whichįur color seems to have the greatest overall selective advantage,Ī. Shows that there are more dark mice living on the dark substrateĪnd more light mice living on the light colored substrate. The numbers of each genotype of mice in the questions above It's called "Natural Selection and the Rock Pocket Mouse — HHMI BioInteractive Video." Thank you.Īnswer the following questions about natural selection and evolution:ġ. There is a video on YouTube that's 10 minutes long that you can watch to answer these questions if you don't understand. Please answer with full sentences please. What does this tell you about the various dark-colored rock pocket mouse populations? Scientists studying rock pocket mice noted while dark-colored mice from two different populations living hundreds of miles apart looked nearly identical, their dark color was caused by two different genes. In the case of rock pocket mice, explain the specific pressure that the mice are facing on a regular basis.Įxplain why the rock pocket mice in the dark lava environment have dark fur over their backs, heads, and legs, but have white underbellies. What is the process that maintains the differences in mouse fur color? The mice maintain their different colors in different habitats over time. How does this process occur biologically? SOLVED: Answer the following questions about natural selection and evolution:ĭark-colored mice first appeared in a population of light-colored rock pocket mice.
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