Evolution

No, natural selection does not create variation within a species. Instead, natural selection acts on existing variations within a population, favoring traits that increase an individual's chances of survival and reproduction in a given environment. The variation itself arises from mechanisms such as mutations, genetic recombination, and gene flow.

Because viruses are single-cell organisms, they can mutate (evolve) quicker than complex, multi-cell organisms, where evolution gradually happens over time spans that humans can hardly fathom. Viral mutations give evolutionary biologists the opportunity to observe the process within timespans a human being can grasp. It not only supports the theory of evolution, but confirms it with demonstrable evidence.

The main cause of evolution is natural selection, which is the process where organisms that are better adapted to their environment survive and reproduce more successfully than those that are not as well adapted. This leads to the passing on of beneficial traits to future generations, causing populations to change over time.

The finches on the Galapagos Islands helped him, as they gave him the basis of his idea of natural selection, which was the backbone of his Theory of Evolution. The birds beaks had altered slightly to enable them to eat the various foods available on their respective islands. This observation then prompted Darwin to extrapolate the data, and say that these small changes could eventually result in a fish turning into a reptile.

It means a synthesis was created between systematic biology, population biology, genetics, paleontology and botany to form the modern theory of evolution by natural selection. Before 1930 all biologists, and other disciplines, were confirmed in evolution but not all were sold on natural selection as the main driver of adaptive change, especially geneticists. By mathematical paraphernalia showing that gradual genetic change over time could drive evolution and a broad agreement among the other branches of biology and earth science we have the modern synthesis, some times called the Neo-Darwinian synthesis.

Can identical twins have babies? Yes.

A cloned animal, except for its age, is indistinguishable from an identical twin. Depending upon how it was cloned, the telomeres of its DNA may be shortened, but this would have little impact on its ability to breed.

In short, yes, cloned animals may have babies, and live out their lives as naturally as uncloned organisms, and this has been demonstrated in numerous cloned species.

Organisms can have physical defenses like camouflage or spines, chemical defenses like toxins or bad taste, behavioral defenses like hiding or fleeing, and immune defenses like antibodies or white blood cells to fight off pathogens.

Can be the basis for evolutionary change. When changes occur in the genes of sex cells, these changes can be passed on to offspring and may result in beneficial adaptations over generations, leading to evolutionary change.

Lamarck was the first to create a theory of evolution. He pretty much stated that animals changed over time because they INHERITED their new trait that they had to have to survive. This was disproved.

Charles Darwin found that animals changed due to NATURAL SELECTION. Natural selection is the process in which animals with a certain trait key to survival would survive in their environment and produce offspring more often than the ones without the new trait therefore passing it on to the next generation, and the next one.

Sloths have evolved to have slow metabolisms, long claws for hanging on trees, and a specialized digestive system to break down their leafy diet efficiently. Their slow movement and greenish tinge help camouflage them in the treetops, protecting them from predators.

It depends on what type of Enzyme. Enzymes have different optimum pH depending on the environment they work in, for example and enzyme in the stomach of a human would have a pH of about 2 but an enzyme in human saliva has an optimum pH of 5.6.

Protein comparisons, ie. DNA comparisons contribute to evolutionary theory by separating organisms in the plant and animal kingdoms. They go so far as to even separate individuals from one another within the same species. AKA Genetic Code.

Organisms that are less fit can die before they reproduce. This is statistically more likely for such organisms. Organisms that are less fit have problems getting mates as they are passed over in greater numbers than fit organisms. Organisms that are less fit can not bring the offspring to term and provide as well for the offspring as fit organisms can. Organisms that are less fit pass on to their progeny the genetic insults that they carry, thus their offspring are less fit also. And many other reasons could be thought of here, so you think of some reasons yourself.

The environment and ecological niche play a large role in determining the kind and size of animals. Factors such as available resources, competition, predation, and evolutionary history all influence an animal's size and species. Natural selection also plays a significant role in shaping the characteristics of different animal species.

Charles Darwin proposed his theory of evolution through natural selection in his 1859 book, "On the Origin of Species." This work revolutionized the field of biology and established him as the father of modern evolutionary theory.

Malthus wrote a book that explained how resources increased arithmetically while human population increased geometrically ( exponentially ). So Darwin used this idea in showing that more organisms are born than can be supported by the environment and this set up a struggle for existence in which those organisms better suited to survive and reproduce in the immediate environment would leave more descendents in the population over time.

There is only one evolutionary theory in biology. It is the population genetics model that explains the emergence of new species as the result of reproductive variation, genetic divergence and differential reproductive success.

1. Natural selection can lead to individuals with certain combinations of polygenic traits having higher fitness, increasing their likelihood of passing on their genes to the next generation.
2. It can drive the frequency of alleles that contribute to favorable trait combinations up or down in a population over time.
3. Natural selection can influence the distribution of phenotypic variations for polygenic traits, favoring those that provide a survival or reproductive advantage in a specific environment.

The mass of the star is the most influential factor in determining its rate of evolution. More massive stars have shorter lifespans and evolve more quickly, while lower mass stars evolve more slowly over much longer timescales.

The discovery of discrete inheritance by Gregor Mendel. This genetic finding was combined with evolutionary findings to form the modern evolutionary synthesis that is still, with modification, the theory of evolution by natural selection today.

Yes, the ventral nerve cord is a character found in chordates, not non-chordates. It is a defining feature of chordates, running along the belly side of the body and often involved in coordinating motor functions.

The evolution of four limbs allowed early tetrapods to transition from the water to land, leading to the colonization of terrestrial environments. This evolutionary change enabled animals to move more efficiently, access new food sources, and escape predators. It also laid the foundation for the diversity of terrestrial vertebrates we see today.

Walking upright allowed humans to free their hands for carrying objects, tools, and weapons. It also improved visibility, allowing them to spot predators and prey from a distance. Additionally, it helped with energy efficiency and endurance when traveling long distances.

The absence of the selection pressure malaria. Without selection, in the form of the malarial environment, the sickle cell allele will be lost in the overall US population. Even the heterozygous condition is somewhat deleterious and, statistically without malarial selection pressure the allele will be selected out.