Human Biology Essay Chicken Business Plan
Even traits that develop reliably in all individuals, such as the vertebrate eye, require environmental inputs over the course of development.Place a patch over the eye of a developing vertebrate, and the eye will fail to develop.” The first question is inherently about the relationship between the organism and its environment and arises primarily when the current environment becomes different from the EEA. To provide a concrete example, imagine a lizard species adapted to live in the rainforest that is suddenly transported to the desert (alternatively, the lizard can stay where it is and the climate can change).The phenotypic properties of the lizard don’t change; they simply have different consequences in the new environment than they did in the old environment.”—which I take to mean “What are the phenotypic properties of species X?”—must be answered on the basis of the past environments inhabited by species X.” Now imagine placing any given species in a different environment than its past range of environments.
Any given phenotypic trait therefore cannot be analyzed in isolation from other traits, but rather as part of a genetically influenced developmental system. Nikko Tibergen, who shared the Nobel Prize in 1973 for helping to found the science of ethology, stressed that four questions must be addressed to fully understand any particular trait: (1) Why does the trait exist, compared to many other traits that could exist, often (but not always) based on the winnowing action of natural selection? (3) How did the trait evolve over a period of generations?(4) How does the trait develop during the lifetime of the organism?Tinbergen posed these questions in an article titled “The Methods and Aims of Ethology,” but they also describe the methods and aims of evolutionary biology as a whole. In this fashion, evolutionary biologists provide answers to the question, “What does it mean to be species X?It is important to recognize these as separate questions before relating them to each other.We can begin by asking a third question—“What does it mean to be species X?Monarch butterflies sequester the toxic compounds of milkweed plants for their own defense and undertake an amazing migration to survive the seasons.Polar bears are white to conceal themselves from their prey and have myriad other adaptations to survive the arctic environment.No species is perfectly adapted to its environment, and all species bear vestiges of the far distant past, reflecting the fact that evolution is a path-dependent historical process.The first vertebrates were fish and all subsequent vertebrates, such as mammals, bear the marks of their fishy origin. In addition, all organisms are a product of development over the period of their lifetimes.Perhaps it is so maladapted that it goes extinct immediately—like a fish out of water.Perhaps it survives and reproduces well enough to remain in existence as a population, in which case natural selection will begin to change its properties so that it becomes better adapted to its new environment.