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Published byHendri Wibowo Modified over 6 years ago
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VARIATION Variation - heritable differences of a genetic trait
Within populations, individuals may vary in observable traits Ex: Peppered Moth In most populations, traits will typically follow a bell curve shape Most individuals in the middle of the traits; lesser individuals at the extremes New variations in populations are often caused by mutations
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NATURAL SELECTION Natural Selection - Organisms with traits that are favorable to the environment will reproduce at a higher rate 4 Types of Natural Selection: - Stabilizing Directional Disruptive Sexual Stabilizing Selection: individuals with an average form of a trait have the highest fitness Ex: Large lizards: seen easily; eaten first Small lizards: slow; eaten first Medium sized lizards are the most fit since they can hide easily and be fast enough to escape predators
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NATURAL SELECTION Directional Selection: Organisms with a more extreme variation of a trait will be most fit Ex: Giraffe with long neck during a drought Disruptive Selection: Organisms with either extreme variation are more fit Ex: Limpets are a marine animal that live in the shallow waters on rocks. The rocks are light or dark colors…
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NATURAL SELECTION Sexual Selection: selection based on mating preference Intrasexual: males fighting other males and winner gets to mate with female Ex: Elephant Bull Seal Intersexual: attracting a mate Ex: Peacock Frigate bird
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NATURAL SELECTION
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