An Introduction to Evolution (Main Source: University of California Museum of Paleontology Website) • The Definition: Biological evolution, simply put, is descent with modification (Darwinian evolution). • Evolution is currently defined as a change in the gene frequencies of a population through generations. Evolution occurs when population composition changes. • Macroevolution and Microevolution
An Introduction to Evolution (Main Source: University of California Museum of Paleontology Website). The Definition: Biological evolution, simply put, is descent with modification (Darwinian evolution). - PowerPoint PPT Presentation
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An Introduction to Evolution(Main Source: University of California Museum
of Paleontology Website)
• The Definition:Biological evolution, simply put, is descent with modification (Darwinian evolution).
• Evolution is currently defined as a change in the gene frequencies of a population through generations. Evolution occurs when population composition changes.
• Macroevolution and Microevolution
An Introduction to Evolution
• Biological evolution is not simply a matter of change over time
An Introduction to Evolution
• The central idea of biological evolution is that all life on Earth shares a common ancestor
The History of Life:Looking at the Patterns
• The central ideas of evolution are that life has a history—it has changed over time—and that different species share common ancestors.
The Family Tree
Descent with Modification 1. Beetles on a diet
Imagine a year or two of drought in which there are few plants that these beetles can eat. All the beetles have the same chances of survival and reproduction, but because of food restrictions, the beetles in the population are a little smaller than the preceding generation of beetles.
Descent with Modification2. Beetles of a different
colorMost of the beetles in the population (say 90%) have the genes for bright green coloration and a few of them (10%) have a gene that makes them more brown. Some number of generations later, things have changed: brown beetles are more common than they used to be and make up 70% of the population.