Disambiguation Links – Darwinian Evolution (C/N)
In general, “evolution” describes the process by which successive change occurs, resulting in the development of a new entity from a previously-existing one. The concept of evolution is one of the vital aspects of our understanding of biology; however, in common parlance, it is also used to describe changes in society, technology, and the character of an individual person.
All living things are inherently evolving from one generation to the next. All currently-known organisms use RNA and DNA to carry genetic information; when a parent organism reproduces, its genetic information is inherited by its offspring. Genes may also be controlled by smaller particles which can be inherited as well; this regulatory process is called epigenetics. Mutations, which are random alterations to the genetic code caused by external or internal factors, often occur during cellular reproduction. Most mutations have no effect, but some can be harmful, while on rare occasions a random mutation may actually benefit the organism. These imperfections drive the process of biological evolution.
Changes in the environment may cause a previously-harmless mutation to become beneficial or harmful, or cause a beneficial mutation to no longer be advantageous. In any given population of organisms, there will be some level of genetic diversity; some of the organisms will have traits that benefit them in that particular environment, while others may have traits that hinder them. Those with more beneficial traits will have a better chance at reproducing, and thus passing on the genes and epigenes that cause those beneficial traits. This is called adaptation. After several generations, these adaptations will be more common in the population, while traits that decrease the creature’s chance of survival and reproduction will be less common. This process is called natural selection, and is often termed “survival of the fittest.” In this case, “fitness” does not exclusively mean physical strength, but instead refers to the organism’s ability to survive in its environment.
In the short term, only small changes within a population will be observed. The overall evolution of life is often thought of as a series of massive, dramatic changes that occurred throughout the past, but this is a highly simplified interpretation. In reality, the incredible diversity of life known today is only possible due to the immense age of Earth. Life is believed to have first occurred on the planet shortly after its formation over four billion years ago, and has evolved continuously since then; every generation is capable of only small change, but over billions of years, the extent of change that is possible becomes much greater. Furthermore, one species does not simply become another, but rather slowly progresses from one form to one or more different forms, which should be seen as a continuum. Viewing the entire family tree of life as a continuum is difficult for many people to visualize, so it is frequently simplified for ease of understanding.
The physical environment (including conditions such as temperature, atmosphere, humidity, climate, and soil type) is a major cause of natural selection, but it is not the only one. Ecology is another significant force that drives evolution. All living things must obtain energy to carry out their basic biological functions, and so many of the most noticeable adaptations are centered around this. In predators, adaptations serve to help the creature successfully capture and kill its prey. Predatory species may have adaptations such as sharp claws, serrated teeth, powerful limbs, and increased intelligence. Other, more passive feeders do not have these features; for example, the expansive leaves found on some plants have evolved to maximize the surface area where photosynthesis can occur.
Natural selection is also driven by competition with other creatures for resources. Organisms that have traits that allow them to dominate resources will usually do better than their less competitive neighbors. This does not only apply to species that compete with one another, but also to competition within the same species. In many animal species, mate selection is one of the most important drivers of evolution. It is common for male animals to compete with one another using both sensory and physical displays, with the male who possesses the most desirable traits often winning the competition. Females will usually choose the males with the greatest evolutionary fitness; however, in some cases, a trait that actually reduces fitness may be selected for instead, such as the tail of the male peafowl. In this case, sexual selection can put more evolutionary pressure on a species than other forms of natural selection. Males also have some influence in sexual selection, as they can choose to mate with females that they believe have the most desirable traits.
No species exists in isolation; they all interact with other forms of life. As a result, many adaptations are the result of coevolution, or two or more species influencing one another’s evolution. One of the classic examples is pollination. Flowering plants have coevolved with insects such as beetles, butterflies, and bees; those flowering plants that can best attract animals capable of carrying their pollen will have better reproductive success. Other examples include predator-prey interactions, which encourage the evolution of defense mechanisms in the prey (such as camouflage, horns, and poisonous qualities) and hunting mechanisms in the predators.
Coevolution also results from other ecological interactions, especially where symbiosis occurs. Many organisms that exist in symbiotic relationships benefit one another, but a great many are also parasites. Some parasitic organisms have coevolved with their hosts to such a degree that they cannot survive or reproduce without the host at all.
Resources in nature are limited, but under theoretical ideal conditions, the growth of life is not. As a result, not all organisms will survive until old age, and many will not manage to reproduce. When the last member of a genetic lineage dies without any offspring, its lineage is said to have become extinct. This can happen on a small scale, as with families and other genetically distinct groups, or on a very large scale with entire groups of species dying. Extinction may occur for any number of reasons; perhaps the lineage was outdone by a more competitive one, or perhaps a change in the environment occurred too quickly and severely for it to adapt over the generations. When an event results in the death of extreme numbers of species within a relatively short time, it is called a mass extinction event. There have been several mass extinction events throughout prehistory, as well as one that is presently occurring.
An intelligent species that understands heredity can intentionally cause evolution. This is called artificial selection, and it has been practiced by the human species for thousands of years. Among the most classical examples is the domestic dog (Canis familiaris), which evolved from wolves (Canis lupus) under the direction of humans who controlled their breeding as much as 15,000 years ago. Humans have guided the evolution of many other animals and plants by selecting traits that they desired in the species and breeding individuals with those traits. Some of the species bred by humans include cats, goats, cattle, chickens, pigs, and plants such as bananas.
Advances in our understanding of genetics, along with improved technology, has allowed artificial selection to go a step further. Using modern genetic engineering techniques, scientists are now able to manipulate genes directly (though the epigenome is still being understood). Instead of choosing desirable traits and breeding organisms with those traits for generations, a team of scientists can identify the functions of particular genes and edit them as needed to express the desired traits in a single generation. This may involve the insertion of a new gene, removal of a certain gene, or some combination of the two. When genes from more than one species are involved, the process may be called genetic hybridization. This was first accomplished in 1972, with simian vacuolating virus 40 and the lambda virus being combined by Dr. Paul Berg. Genetic modification has been greatly advanced by International Genetics Technologies, Inc. chief geneticist Dr. Henry Wu, who has used genetic engineering to pioneer de-extinction and eventually the creation of entirely new genera of plants and animals.
While evolutionary adaptations can be observed in every living thing, some particularly exciting examples can be found in the field of paleontology (and, since InGen, de-extinction as well). This gives insight into how life on Earth has evolved in the past, and how selective pressures could cause it to evolve in the future.
The public has always been fascinated by predatory dinosaurs, so their evolutionary adaptations are likely the most familiar. Early theropods such as Herrerasaurus already possess many of these traits, such as sharp teeth and claws, grasping hands and feet, and powerful leg muscles. These become even more prevalent in later theropods; in Herrerasaurus one can observe the groundwork for the incredible speed of Velociraptor and Deinonychus, and the immense crushing jaws of Tyrannosaurus. However, while these species share a common ancestor, it is plainly clear that they have adapted to their roles as predators in different ways. The smaller Velociraptor is adapted for intelligence and fast pursuit, with its long tail counterbalancing its body and its enlarged sickle-shaped raptorial claws for clinging to its prey. Meanwhile, the Tyrannosaurus can still move rather fast, but is more designed for ambush, short chases, and brawling. Its arms, unlike the lanky limbs of Velociraptor, are very small. Some scientists believe that this is an adaptation to allow more energy to go into the development of its incredibly powerful jaws.
Both of these theropods’ coloration, though likely affected by InGen’s genetic engineering techniques, serve to camouflage them in their environment. This makes them less visible to both predators and prey alike, and is common among animals. Some theropods feature brighter colors that are used in social displays, such as the crests and frill of Dilophosaurus, bright head and nasal horn of Ceratosaurus, and the tall sail of Spinosaurus. Social display structures are also found in other types of dinosaurs; the head crests of hadrosaurs like Corythosaurus and Parasaurolophus are used both for visual displays and to create vocalizations to communicate. Some adaptations serve a dual purpose, such as the horns and bony frill of Triceratops, which are used for both display and combat; they may be used to establish dominance among others of their species, or to attack and defend against predators. Others, such as the armor of Ankylosaurus, is used predominantly for defensive purposes.
Herbivores also have adaptations for feeding, even though their prey is often easier to overcome than the prey of carnivores. Plants do have defense mechanisms, which herbivorous animals must adapt to. They also must adapt to competition from other herbivores. Hadrosaurs such as Edmontosaurus evolved the ability to chew their food, making them more efficient eaters and able to target a wider variety of plants. The famously long necks of sauropods are another example of feeding adaptations; some, such as Apatosaurus, are adapted to feed lower to the ground, while the impressively tall Brachiosaurus is adapted to feed at the tops of trees. Long necks are taken to an extreme in Mamenchisaurus, which has the longest neck of any known animal.
Some of the more spectacular examples of evolution are those that allow species to move into a different medium in nature; the first such example was probably the ability of aquatic creatures to exist in terrestrial environments. Since then, some terrestrial species have adapted back into aquatic environments, while some have developed wings that allow them to fly. InGen has recreated examples of these in the form of mosasaurs (Tylosaurus and Mosasaurus, which are related to monitor lizards) and pterosaurs (Pteranodon, Geosternbergia, and Dimorphodon).
Artificial evolution, of course, has also received much attention over the past few years due to the work of former InGen geneticist Henry Wu. Technically, he and InGen’s other geneticists had practiced genetic engineering since the very beginning of the Jurassic Park project; much of the paleo-DNA recovered from Mesozoic amber was decayed due to its extreme age, so Wu replaced decayed segments with donor genes. These originated from extant animals, including several species of frog. Many of his genetic engineering techniques resulted in unintended traits appearing in the cloned animals, making them appear physically different from their fossil counterparts. Beginning in the early 1990s, he utilized common reed frog (Hyperolius viridiflavus) DNA in species such as Velociraptor, unknowingly using the genes that permit this frog to undergo protogyny in a single-sex environment. These genes integrated successfully into the dinosaurian genomes, allowing them to experience the same protogynous transformation. In many cases, genetic manipulation may have altered the appearances and behaviors of de-extinct life. Particularly dramatic examples have been designated with unofficial species or subspecies names on Jurassic-Pedia to distinguish them from their unmodified counterparts.
Eventually, Wu was able to harness this form of hybridization and intentionally use it to enhance existing species. By 1997, he had succeeded in creating the first scientifically-recognized artificial genus and species, a flowering plant named Karacosis wutansis. His research into artificial evolution would continue for years as he worked in Jurassic World, culminating with the creation of artificial animal genera such as the Stegoceratops and Indominus rex, the latter of which was the first such animal to be fully realized. Further modifying the Indominus genome led to the creation of the genus Indoraptor, which is often considered to have evolved from Indominus due to its being a direct genetic descendant. This would be the first example of a lineage including multiple genera being artificially evolved by genetic engineering.
“Evolution” is often used to describe non-biological phenomena, which may include concepts that are similar to biology or unrelated. It may be applied to the development of social constructs such as language and culture, which change slowly over time as influenced by their environment as well as other internal and external factors. They are affected by small, often random changes, but produce an overall non-random result. This makes societal evolution similar to biological evolution.
The advancement of science and technology are sometimes described as evolution; however, these are unlike biology in that they are almost always purposefully directed. In contrast, biological evolution is non-directional; it simply is the result of selective pressure placed on organisms, and is not goal-oriented. Technological evolution is nearly always goal-oriented and, while it is certainly influenced by environmental factors, is dictated almost entirely by the intentions of its creators.
Individual people, by the biological definition, cannot evolve; the process takes generations. In common speech, though, an individual’s personality traits changing over time as a result of changes in their environment as well as their personal growth are often termed evolution.
Within the Jurassic franchise, the term “evolution” is often used to describe changes and developments that are believed to bring something new. This usually takes the view of evolution being a directional modification process occurring in bold, dramatic steps, which is highly unlike how biological evolution actually works. It was used in one of the taglines for Jurassic Park ///, “Fear Has Evolved,” referencing the idea that the animals in that film were supposed to be more intimidating than those in previous films. The new, vibrant color schemes and overall designs for Jurassic Park /// animals were also said to be “evolved,” particularly in the Velociraptors, which were intended to be more birdlike due to the addition of several bare quills on the head of the male.
The game Jurassic World: Evolution is so titled in reference to its being viewed as a descendant of sorts of earlier park-management games such as Jurassic Park: Operation Genesis, as well as having new designs for management simulators in general.
Evolution as it relates to character development is used in the title of, and theme of, the novel The Evolution of Claire, which gives further insight into the character of Claire Dearing. The book gives more context for her development into a detached business professional, rediscovery of her ability to care for others, and transformation into an animal rights activist.