You are invited to do the probability calculations, but my rough guess is that to get a specific adaptive trait like a color that matches the background, you'd need something in the thousands or maybe millions of tries before it would show up.
Probably a reasonable guess.
13.5 million humans born each year, each with something on the order of 100 mutations.
16.5 million dogs born each year in the US alone.
Variation, Selection and Time: A Recipe for Biodiversity:
quote:
Many varieties of mice are used as model organisms in laboratory experiments all over the world. As a result mice have been extensively studied, including their mutation rates. Mice have 5 billion DNA bases in their genome and mutation at any one base occurs in about 2 out of every billion bases. There are about 1000 bases in an average gene that can be mutated. Multiply 1000 bases per gene times 2 mutations per billion bases and we get that mutation occurs in a specific gene in about 500,000 individuals. Mice breeding labs have found several mice mutants involving fur color traced a gene called MC1R. There are 10 sites within this gene that if mutated cause the mice’s coat color to be black even if they carry only one copy of the gene (all mice have 2 copies of every gene just as human have 2 copies of every gene — 1 from your mother and 1 from your father).
Table 3. Mice Mutation Rates
s
Mutation Rate | 2 per 1,000,000,000 bases
|
Number of sites in MC1R that can be mutated to make a mouse black | 10
|
Number of copies of MC1R gene | 2 |
On your answer sheet, calculate the number of mutant mice having a black causing mutation in the MC1R gene that you would expect in 1 billion mice. What are the odds of just one mouse having a black causing mutation in the MC1R gene? [Answer question 7]
Now let’s look at mice population size and birth rates — factors that play a role in the determining how long it takes for one mutation to arise. Pocket mice live in population sizes that range from 10,000 to 100,000 individuals. These mice also have a high reproductive rate — on average 5 babies are born to every female per year. Calculate the number of babies born in a population of 10,000 individuals each year. [Answer question 8]
Multiply answer 8 by answer 7 [Answer question 9]
Your calculations should reveal that in 1,000,000 years, a black-causing mutation will occur independently 1000 times. Every 1000 years you could say that our population of 10,000 pocket mice {i.e. a small population - JonF}hit the black mutation jackpot! How often would a larger population, say 100,000 individuals hit the jackpot? Show your calculations on your answer sheet. [Answer question 10]