Evolution is a remodeling process in which ancestral structures that functioned in one capacity become modified as they take on new functions. Fossils provide visual records in a complete series showing the evolution of an organism.
Most fossils are found in sedimentary rocks and the oldest known fossils are of prokaryotes. Biogeographic studies show that life in different parts of the world has distinctive evolutionary histories. Modern evolutionary biologists recognize the importance of geological events.
Similarities among the structures of animals occur due to common evolutionary origin. Closely related organisms go through similar stages in embryonic development.
The animals have homologous biochemical processes like homologous structures; so, molecular biology has provided a lot of important information about evolutionary relationships.
Evidence of Biological Evolution
Evolution is a scientific theory supported by an overwhelming quantity of evidence. Some Christians fear that accepting the theory implies rejecting God as a developer. But that just does not follow. Christians accept scientific theories about the weather condition, the development of mountains, and even the conception and development of specific human beings while still acknowledging that God is the creator and sustainer of these things.
So, providing a scientific description for a process does not eliminate a genuine theological description of the procedure too. Advancement leaves observable indications. Darwin’s theory of evolution was mainly based upon the evidence from the geographical distribution of species and from the fossil record. Nevertheless, there has actually been numerous evidence as biology advanced. New discoveries continue to verify the evolutionary view of life. Let us discuss now a few of the pieces of evidence.
The geographic distribution of organisms in the world follows patterns that are best explained by development in conjunction with the motion of tectonic plates over geological time. Broad groups that developed prior to the breakup of the supercontinent Pangaea (about 200 million years ago) are distributed worldwide.
Groups that evolved considering that the break up appear uniquely in regions of the planet, for example the unique flora and animals of northern continents that formed from the supercontinent Laurasia and of the southern continents that formed from the supercontinent Gondwana. The existence of Proteaceae in Australia, southern Africa, and South America is best discussed by the plant family’s existence there prior to the southern supercontinent Gondwana breaking up.
Consider armadillos, the armored mammals that live just in America. The evolutionary view of biogeography forecasts that modern armadillos are modified descendants of earlier forms that inhabited these continents, and the fossil record confirms that such forefathers existed.
The Fossil Record
Fossils are either the actual remains or – traces of organisms that lived in ancient geological times. The organism may be embedded in the sand, resin, or ice, or an impression or cast is made from the body parts, the tissue being changed or petrified by silica or calcium carbonate minerals. The majority of fossils are discovered in sedimentary rocks.
The succession of fossil forms is strong evidence in favor of evolution. It supplies a visual record in a complete series showing the evolution of an organism. For instance, evidence from biochemistry, molecular biology, and cell biology positions prokaryotes as the forefathers of all life, and predicts that bacteria need to precede all eukaryotic life in the fossil record. Certainly, the earliest known fossils are prokaryotes.
Another example is the chronological look of the different classes of vertebrate animals in the fossil record. Fossil fishes, the earliest vertebrates, with amphibians next, followed by reptiles, then mammals and birds. This series follows the history of vertebrate descent. The evolution of the horse provides an example of such a history.
Physiological similarities between species grouped in the same taxonomic classification bring another support to the theory of the Descent with the modification. For instance, the same skeletal components comprise the forelimbs of humans, cats, whales, bats, and all other mammals, although these appendages have really different functions.
The basic similarity of these forelimbs is the consequence of mammals from a common forefather. The arms, wings, clippers, and forelegs of different mammals are variations on a common physiological theme that has actually been modified for divergent functions. The resemblance in characteristics arising from common origins is referred to as homology, and such physiological signs of development are called homologous structures.
Comparative anatomy supports that evolution is a remodeling process in which ancestral structures that operated in one capability ended up being modified as they tale on new functions. The lower parts of a lowering plant are homologous. They are considered to have evolved from leaves, to form sepals, petals, stamens, and carpels.
Homologous organs are functionally different but structurally alike e.g., Forelimbs of humans, bat, horse, whale, and so on are examples of divergent evolution.
Analogous organs are functionally alike but structurally different e.g., wings of a bat, birds, and insects, and so on are examples of convergent evolution.
Vestigial organs are historic remnants of structures that had essential functions in ancestors however are no longer important presently. For example, the skeletons of whales and some snakes retain vestiges of the pelvis and leg bones of walking ancestors, vermiform appendix in carnivores, ear muscles in humans, etc.
Closely related organisms go through similar phases in their embryonic development. For instance, all vertebrate embryos go through a phase in which they have gill pouches on the sides of their throats. At the embryonic phase of development, resemblances between fishes, frogs, snakes, birds, humans, and all other vertebrates are much more evident than differences.
As development advances, the various vertebrates diverge increasingly more, taking on the distinctive attributes of their classes. In fish, for instance, the gill pouches become gills; in terrestrial vertebrates, these-embryonic structures end up being modified for other functions, such as the eustachian tubes that connect the middle ear with the throat in humans.
Relative embryology can often develop homology among structures, such as gill pouches, that become so modified in later development that their typical origin wouldn’t be apparent by comparing their fully developed forms.
The comparison of biochemical processes with ancient species is called comparative biochemistry. For instance, the very same systems for trapping and transforming energy and for structural proteins from amino acids are nearly identical in almost all living systems. DNA and RNA are the mechanisms for inheritance and gene activity in all living organisms.
Evolutionary relationships among species are reflected in their DNA and proteins– in their genes and gene products. If two species have genes and proteins with a series of monomers that match closely, the series should have been copied from a typical ancestor. For instance, a typical hereditary code brings evidence that all life is related.
Molecular biology has therefore provided strong proof in support of evolution as the basis for the unity and diversity of life. Likewise, taxonomically remote organisms, such as humans and bacteria, have some proteins in common. For instance, cytochrome c, a respiratory protein is found in all aerobic forms.