New species are usually formed by speciation - the act of an earlier species splitting into two. This takes place at a certain time and place. These species may then travel to new places. but they may be stopped from doing so due to mountains and seas, and by climate. Some species may never arrive at certain places. This means that two places with similar climate can often have different kinds of animals and plants. For example, marsupials which live in Australia, and animals which moved because of the Great American Interchange - which meant that there were very different species which came to live in North America and South America.
Different types of animals and plants move in different ways. It is easier for birds and insects to fly through the air, but it is easier for fish to swim in the sea. There are very different species in North America and South America, and fresh-water fish do not come in many types.
It can then be said that:
The scientific theory of biogeography grows out of the work of Alexander von Humboldt (1769–1859), Hewett Cottrell Watson (1804–1881), Alphonse de Candolle (1806–1893), Alfred Russel Wallace (1823–1913), Philip Lutley Sclater (1829–1913), and other biologists and explorers.
Wallace studied the distribution of flora and fauna in the Amazon Basin and the Malay Archipelago in the mid-19th century. Wallace and Sclater saw biogeography as a source of support for the theory of evolution. Key findings, such as the sharp difference in fauna either side of the Wallace Line, can only be understood in this light. Otherwise, the field of biogeography would be a purely descriptive one.
Both Darwin and Wallace gave a great deal of attention to oceanic islands as offering examples of evolution, especially speciation. Darwin worked a lot in the Galapagos islands This interest was revived by "The theory of island biogeography" by Robert MacArthur and E.O. Wilson in 1967. They showed that the variation in species in a single area could be predicted if one knew the habitat area, immigration rate, and extinction rate.
It was realised that habitat fragments are like islands. They can be investigated by the same methods. This spurred the development of conservation biology.
Genome analysis allows scientists to test theories about the origin and dispersal of populations, such as island species. It allows biologists to test theories about where the species come from.
Biophysics
Biophysics is a science where the laws of physics are used to study biology, the science on life and living things. Unlike biochemistry and molecular biology, sciences where macromolecules or "large" groups of molecules are studied, biophysicists study single or small groups of molecules.
Macromolecule
A macromolecule is a molecule with a large number of atoms. The word is usually used only when describing polymers, molecules which are made up of smaller molecules called monomers. All organic monomers are based on carbon, usually with hydrogen, oxygen and nitrogen. There are inorganic macromolecules based on other monomers.
Examples:
Dendrology
Dendrology is the science of trees and other woody plants such as shrubs or lianas. The word "dendrology" comes from Greek words δένδρον meaning "tree" and λόγος meaning "study".
Entomology
Entomology is the science of insects. People who study insects are called entomologists. Insects have been studied since prehistoric times, but it was not until as early as the 16th century that insects were scientifically studied.
Some entomologists study how insects are related to each other. Others study how insects live and reproduce because we do not know very much about some kinds of insects. Other entomologists study ways to keep insects away from crops that people use for food. There are billions of unknown species throughout the world and taxonomists categorize the newly found.
Entomologists meet to talk about their study of insects and to share ideas, just as all scientists do.
Ethology
Ethology is the scientific study of animal behaviour (U.S. "behavior"), and a sub-topic of zoology. Ethology overlaps, to some extent, with psychology. Psychology is a social science which studies human behaviour, but many psychologists have done experiments on learning in animals. Ethology studies animal behaviour, but many ethologists have been interested in human behaviour.
An American specialist on ants, William Morton Wheeler, first used the term 'ethology' in English in 1902.
The study of animal behaviour, which had been going on in an anecdotal way since Aristotle, had its roots in natural history. It became more scientific during the 19th century. The French zoologist Étienne Geoffroy Saint-Hilaire was the founder of ethology in Europe, and his son Isidore produced a three-volume encyclopaedia "Histoire Naturelle Générale". In the third volume he talked about animal behaviour in almost modern terms. The entomologist J.-H Fabre (1823–1915) was a remarkable observer of natural life. His popular writing on natural history kept ethology alive in Europe.
Douglas Spalding (1841–1877) was a British biologist who was the first to notice the effect called imprinting. Instinct and imprinting were the first scientific concepts in ethology.
He was able to prove that the behaviour of chicks after hatching from the egg happened even when they had no experience, practice or even information from the senses. Therefore, the capacity was inherited.
Studies by Charles Otis Whitman, Oskar Heinroth and Julian Huxley set the tone in the 20th century. This work was mostly on bird behaviour, especially mating behaviour. The behaviour of birds played a big part in early ethology, but there was a start to studying our nearest relatives. Wolfgang Köhler's "Mentality of Apes" was a landmark in the study of primates. In 2020, Dr. Tobias Starzak and Professor Albert Newen from the Institute of Philosophy II at the Ruhr University Bochum proposed that animals may have beliefs despite these being more difficult to determine than humans.
The next generation began during the 1930s with the work of Austrian biologists Konrad Lorenz and Karl von Frisch, and the Dutch biologist Niko Tinbergen. The three men were joint winners of the Nobel Prize in Physiology or Medicine for 1973.
Lorenz is famous for his 'longitudinal' studies: he lived with the animals he researched, and made observations throughout their lives. Then he wrote about what he had discovered in long, very readable papers. He researched instinctual behaviour, which he called 'fixed action patterns' (FAPs). Lorenz popularized FAPs as instinctive responses that would occur reliably in the presence of specific stimuli (called sign stimuli or releasing stimuli). von Frisch worked on communication in honey bees: the famous 'bee dances'. Tinbergen experimented with the stimuli which trigger fixed action patterns. He found out that artificial super-stimuli could often work better than the natural stimuli.
Ethology is a combination of laboratory and field science, with a strong relation to certain other disciplines—e.g., neuroanatomy, ecology, evolution. Ethologists are typically interested in a behavioural process rather than in a particular animal group and often study one type of behaviour (e.g. aggression) in a number of unrelated animals.
In the 1960s Nico Tinbergen set out a framework for research on behaviour. It involved four questions and their answers.
The only scientific explanation for an animal’s behaviour is that it is well adapted for survival and reproduction in its environment. A trait is the result of its past contribution to survival. In practice, this is simple. For instance, birds fly south in the winter to find food and warmth, and mammalian mothers nurture their young, thereby having more surviving offspring.