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The Geographic Secrets of Life: Do you know why animals look different in different places?
We often find animals with various characteristics in different regions. What scientific principles are hidden behind this? An animal's appearance, behavior, physiological condition, etc. are all affected by the environment in which it lives. The specific manifestation of this influence is reflected in the concept of "cline". A CL is a measurable trait gradient that varies continuously across a species' geographic range and that responds not only to the environment but is also closely associated with gene flow and natural selection.
The existence of Klein is closely related to the evolution of biodiversity. It can be said that Klein is a natural phenomenon formed in the process of organisms fighting against survival challenges in a specific environment.
The formation of clades is driven primarily by two forces: selection and gene flow. Selection forces organisms to adapt to the local environment, so the genotype or phenotype of organisms will show obvious differences in different environments. For example, in Australia, birds in the north are generally smaller than those in the south, a result of selective evolution caused by climate change and resource limitations in the north.
In addition, the emergence of Klein also requires a certain degree of gene flow, which allows organisms in different geographical areas to maintain certain genetic interactions even if they are different, thereby reducing the differences caused by natural selection. However, stronger gene flow may weaken local adaptation and lead to smaller Klein. For example, the dramatic color changes of the peppered moth in Britain in the 19th century due to industrial pollution vividly illustrate Klein's formation process.
The term "klein" was first coined by Julian Huxley in 1938 and is derived from the Greek word meaning "to tilt".
The formation and evolution of Klein
After years of evolution, Klein usually occurs in two situations: original differentiation and secondary contact. Primitive differentiation is caused by environmental changes. When a certain organism survives in a new environment, it will produce characteristic changes to adapt to the local environment. This is a gradual evolutionary process, in which differences in the external environment provide selection pressure.
Secondary contact occurs when two previously isolated species come together again due to environmental changes. Such a reunion usually results in a situation such as a "hybrid zone". The same genes adapt to changes in the environment, resulting in significant differences in certain traits between the two groups. At this time, natural selection will exert pressure on the corresponding genotypes to maintain differentiation between different groups.
It is further stated that the structure and morphology of the Klein reflect the degree of variation in characteristics within a geographic range, which is affected by a variety of factors, including gene flow between populations and environmental selection forces.
This phenomenon not only occurs in animals, but also in plants and invertebrates, which are also affected by Klein. In the case of the black lead moth, its color changes in different environments reflect how geographic features and selection pressures are intertwined.
Klein's Type
According to Huxley's classification, Klein can be divided into continuous Klein and discontinuous Klein. The former means that all populations maintain gene flow and form gradual changes, while the latter shows breaks between populations and gradual differentiation.
Most organisms show continuous adjustment within their geographic range, maintaining diversity through the exchange of genes between them. Some are isolated and broken due to geographical barriers or other factors, thus forming discontinuous Kleins. This allows us to observe these organisms and trace their evolutionary trajectory and the forces of natural selection at work.
As Gottes observed, climate change is linked to the evolution of plants and animals, a phenomenon that went hand in hand with the formation of Klein.
For example, under environmental selection, birds living at different latitudes will have variations in color and size, and even their behavior patterns will change accordingly. This phenomenon not only makes people think, but also promotes biologists' understanding of biological evolution and its environmental adaptation. Have you ever wondered how these changes affect the survival and reproduction of animals?
