The Animals Say, "Evolution Ain't Bunk" Quiz

Answer: Allopatric speciation

Lakes act as islands for these guppies, each lake separated by dry land, preventing interbreeding of the different populations. Different lakes may have different selective pressures, e.g. types of predator or muddiness of the water, and therefore different genes will be advantageous. High levels of predation in one lake will favour duller, less conspicuous guppies, whereas in lakes with fewer predators, brightly coloured males can flourish and attract more females. Over time, the gene pools of separate populations will become so different so as to prevent interbreeding (i.e. speciation occurs). Because this speciation is due to physical barriers, it is known as allopatric.

Answer: The fratricide of hatchling pelicans

Artificial selection is similar to natural selection, but with more rapid results due to harsher selection pressures imposed by humans. The breeding of wild dogs (wolves) to create the myriad of dog breeds found today, and the breeding of cows to produce huge amounts of milk, are two ways in which humans have engineered animals to be of more use to humankind.

Answer: Hybrid zones

The fire-bellied toads (Bombina bombina) and the yellow-bellied toad (Bombina variegata) are classed as two distinct species and form a 10 km wide hybrid zone. In this zone, hybrids flourish, but not to the extent that their parent species are threatened. Both yellow-bellied and fire-bellied toads therefore remain distinct species.

Answer: Sexual dimorphism

In the animal kingdom, it is usually the females who chose who to mate with, as producing offspring generally requires much more input from the mother. Males will therefore compete with one another for mating rights, leading to an evolutionary arms race to acquire the biggest muscles, the brightest feathers, the loudest call, etc. Sperm whales are a great example of sexual dimorphism brought about by sexual selection. Males of the species engage in vicious fights, using their large heads, filled with a substance called spermaceti, as battering rams.

The larger the male, the better the chance they have at emerging victorious from such a skirmish, and this has led to them being up to three times larger than female sperm whales.

Answer: The C-Value Paradox

This paradox generally applies to eukaryotes (animals, plants, fungi etc.). Prokaryotes (e.g. bacteria) have been around for much longer than lions, or conifers, or mushrooms, but generally do not display this trait of junk DNA accumulation. This is because prokaryotic genomes survive in nature by their ability to replicate. Those which replicate most rapidly will be the most successful, and having a small genome (i.e. little/no junk DNA) will accommodate rapid replication.

Answer: Bad design

Bad design (or unintelligent design, when used in a deliberate effort to contrast creationism) describes how the products of evolution, though functional, are often imperfect.
The laryngeal nerve was present in fish, which evolved into our tetrapod ancestors. Although this route between the brain and the larynx was direct in fish, its modification during evolution into modern-day mammals left it unnecessarily long. The laryngeal nerve of a giraffe takes a 5 metre long detour before reaching its destination. This is a more modest (but still wasteful) 1 metre in humans.

Answer: Enzymes which alter genes in the face of selective pressures

Whereas most animals take several years before producing offspring, bacteria can do the same in just days, or hours, or minutes. The inevitability of mutation is not only enhanced by this rapid rate of replication, but the lack of efficient proof-reading complexes (such as those found in many eukaryotes).

The random appearance of a gene coding for penicillin resistance will give a bacterium a selective advantage when in the presence of the antibiotic. Whereas other bacteria die, those which contain the gene coding for resistance survive and replicate, passing on this gene to its offspring. Penicillin resistant bacteria not only pass on their genes vertically (via binary fission), but horizontally, literally sharing their genetic information with other bacteria, which do not necessarily have to be of the same species.

Answer: Runaway sexual selection

The drive to become more visually spectacular (and therefore more attractive to the opposite sex) must be balanced by the ability to stay alive in the face of predation. An animal with a colourful coat may attract more females, but will also be more conspicuous and therefore more susceptible to predation. If there are no predators, runaway sexual selection can occur.

This is clearly seen in the birds of paradise on the island of New Guinea.

Answer: Fin to limb

Tiktaalik caused waves of excitement upon its discovery in 2004. Well-preserved fossils of this creature from the Devonian period were found on Ellesmere island and it was immediately embraced as the "missing link" which explained how fins evolved into limbs around 370 million years ago.

Answer: Convergent evolution

Though almost so similar to make some think they belong to the same genus, the flying squirrel and the sugar glider do not even belong to the same order of animals. The reason for their similarity is due to them experiencing similar environmental pressures, and evolving similar structures (e.g. flaps of skin joining their front and hind limbs) to deal with such pressures.