Victoria's Voyage of Evolution

 I think in general speciation takes a pretty long time, but there are factors that can affect the speed of speciation. Speciation is gradual and occurs along a spectrum, with lineages diverging and hybridizing over time. Speciation also depends on how exactly you define a species - there are many different species concepts, each with their own merits and limitations.  Speciation can occur more rapidly if selection is particularly strong and the resulting change in traits results in reproductive isolation. An example of this is the anole lizards I mentioned in my second blog post. For the anoles, speciation starts to occur over only a few generations. However, even though changes can occur rapidly, they might not persist. Like I stated earlier, species can move up and down the spectrum. According to a study from Oregon State University, lasting evolutionary change often takes about one million years, because the underlying forces driving the adaptation need to also persist, wh...

Pipefish females exhibit elaborate and colorful courting displays in order to compete for males. This is unusual for the animal kingdom as in most other species with strong sexual selection like this, it is the males who court the choosy females. The question is, why are pipefish different?   In the theory of sexual selection, sexually dimorphic species have differing constraints on their reproductive success. In species with different levels of parental care (one essentially does all the raising of offspring while the other only contributes genetic material then dips), one is constrained by the time and energy it has and the other is constrained by how many mates it can have. The parent who will be raising the offspring and investing the most time and energy should therefore be choosy of potential mates so as to ensure the success of their precious offspring. On the other hand, the parent who just needs to get with as many mates as possible will need to compete with others fo...

 One of the cutest creatures in the animal kingdom is the fennec fox, no argument. It's those enormous ears on a little face and body that make it so precious. You might wonder, why does it have such big ears? How/why could they have evolved? The fennec fox's ears are an incredible adaptation for their environment and lifestyle. Fennec foxes are native to the deserts of Northern Africa, such as the Sahara, the hottest desert in the world. Their habitat is incredibly dry, sandy, and hot. So, not the easiest place to live. One way these foxes can survive the extreme heat is because of their ears. The large surface area of the ears helps to dissipate heat and keep the fox cool. Their ears also give fennec foxes incredible hearing that allows them to locate prey hiding in the sand. Pretty neat! You could test if large ears are adaptive by first determining if they are a heritable trait and second if foxes with large ears have a fitness advantage over those without. Sources: https:/...

 Genetic variation is maintained in populations over time through several mechanisms. One of the most basic mechanisms is mutation. Even deleterious alleles that are highly selected against may never fully disappear as there is always the chance for mutation to occur. New mutations can crop up at any point and be passed on to the individual's offspring, adding more genetic variation to the gene pool. As discussed in a previous blog post, high mutation rates can even be selected for under certain conditions such as highly variable environments.  Another mechanism for maintaining genetic variation within a population is immigration. When new individuals from a different population immigrate to a new population and begin interbreeding, their genes are added to the gene pool. Their genes may be different due to novel mutations or adaptations to different environmental conditions in where they immigrated from.  While it is assumed selection eliminates genetic variation, some f...

 Inbreeding is a common form of non-random mating that has both benefits and costs. One form of inbreeding is self-fertilization, which is commonly seen in plants. A single plant in possession of both male and female parts fertilizes itself. A benefit of this is that one individual can reproduce and populate an area by itself. However, there will not be any genetic variation which can be detrimental as the plant population won't be able to adapt well to environmental changes with such a limited gene pool.  Inbreeding can also just be mating between related individuals. A benefit of this is to possibly keep advantageous alleles in your family by only mating with individuals who also possess those alleles. A cost of inbreeding is that it causes a decreases in heterozygosity over time. This can be detrimental to the fitness of the population because it increases the likelihood of an individual being homozygous for recessive deleterious alleles. This results in negative fitness co...

 Mutations - any change in DNA sequence - are the ultimate source of genetic variation and therefore the base material for evolution. There are many different types of mutations, all with varying effects on an individuals fitness. Mutation rates are also important to consider.  Yes, mutation rates themselves can evolve to be higher or lower. Mutation rates can vary from individual to individual, and a higher or lower mutation rate may be beneficial or not based on the type of environment. This means that selection can act on mutation rates, which may lead to evolution. Mutation rates are heritable based on the ability of organism to replicate DNA sequences and repair mistakes, which is encoded in the genome.  High mutation rates would be beneficial in environments with high variation. If the environment is always changing, the ability of the populations that live there to adapt to varying conditions would be paramount. Adaptations arise from mutations, so the more amount ...