Answer to Question #181123 in Evolution for dima

Question

The acoustic lesser wax moth, Achroia grisella, are obligate symbiotes of honeybees (live in association with them).  Males attract females by emitting ultrasonic pulses from their wings. The sound the moth emits can also attract their predators, bats. Wing pulse rate has been demonstrated to be controlled by one gene with two alleles, F (dominant, fast) and f (recessive, slow).  

This population is not currently in Hardy-Weinberg equilibrium, but scientists have determined that environment and other selection factors such as bat predation are stable over recent time. In paragraph form, discuss two other mechanisms of evolution that could be acting on this population, and what information and/or data you would need to support each evolutionary agent. You will be marked according to the written answer rubric on your answer, use of scientific reasoning, and avoiding misconceptions. (5 points) You should have a maximum of 6 sentences.

Answer 1

MUTATIONS

Surviving organisms generally possess traits or characteristics that bestow benefits that help them survive (e.g., better camouflage, faster swimming, or more efficient digestion). Each of these characteristics is the result of a mutation, or a change in the genetic code. Mutations occur spontaneously, but not all mutations are heritable; they are passed down to offspring only if the mutations occur in the gametes. These heritable mutations are responsible for the rise of new traits in a population.

For example, a mutation may allow organisms in a population to produce enzymes that will allow them to eat certain food materials. Over time, these types of individuals survive, while those that don’t have the mutations are more likely to die (natural selection). This is therefore a beneficial mutation.

However, for the mutation to passed down to offspring and help bring about evolution, it has to affect the DNA in the gametes (egg cell or sperm cell).

So in summary, creatures pass on their traits (in the form of DNA) to their offspring via the heredity process. Random recombination and mutations result in offspring with random mixes of traits, which in turn, mix these randomly, and pass them on to their offspring. This allows genetic diversity in the species.

NATURAL SELECTION

Just as mutations cause new traits in a population, natural selection acts on the frequency of those traits. Because there are more organisms than resources, all organisms are in a constant struggle for existence. In natural selection, those individuals with superior traits will be able to produce more offspring. The more offspring an organism can produce, the higher its fitness. As novel traits and behaviors arise from mutation, natural selection perpetuates the traits that confer a benefit.

Natural selection (also known as “survival of the fittest”) is the process by which species adapt to their environment. 

Natural selection leads to evolutionary change when individuals with certain characteristics have a greater survival or reproductive rate than other individuals in a population, and pass on these genetic characteristics to their offspring. 

Selection is a process that each individual is subjected to. Every creature has a unique mix of traits and characteristics. This mix may or may not help them to survive in their environment. Anyone with an unsuitable mix may lead them to death and/ or prevent them from producing offspring. However those with the right mix survive, and have the chance to pass on these traits that helped them to their offspring.

Environmental influences have an effect on all living creatures, and these are known as selection factors. These selection factors can include:

• Predators
• Parasites
• Animals of the same species
• Toxins
• Changes in habitat
• Climate

A good example of natural selection is Darwin’s finches, a type of bird living on a remote island. They are some of the most famous animals in the world of science, and are named after their discoverer, Charles Darwin, how natural selection caused different species to arise from an initial group of stranded mainland finches

Several types of natural selection appear to affect populations. One type, stabilizing selection, occurs when the environment selects against organisms of a population with extreme versions of a trait. Another type of natural selection is disruptive selection. Here, the environment favors extreme types in a population at the expense of intermediate forms, thereby splitting the population into two or more subpopulations. A third type of natural selection is directional selection. In this case, the environment selects for an extreme characteristic.