PPT-23 The Evolution of Populations

The Smallest Unit of Evolution A common misconception is that organisms evolve during their lifetimes Natural selection acts on individuals but only populations evolve Consider for example a population of medium ground finches on Daphne Major Island. A. Darwin’s . Ideas revisited. - it . was more than 50 years after Darwin started to develop . his theory . of evolution before biologists could determine . how evolution . takes place. - about . 10.3 Gene Pools and Speciation. Nature of Science. Looking for patterns, trends and discrepancies—patterns of chromosome number in some genera can be explained by speciation due to polyploidy. Gene Pool. metallicity. gradients . in disk galaxies from . integrated stellar populations. Patricia Sánchez-. Blázquez. . And the CALIFA collaboration. Evolution of the . metallicity. gradients in cosmological simulations. There is overwhelming evidence for the evolution of life on Earth. . Evolution in summary. Evolution occurs when heritable characteristics of a species change. . Evolution at its most fundamental level simply describes a . EVOLUTION OF POPULATIONS. Genes and Variation 16–1. Section 16-1. . A _______________ is a . group of individuals of the same species that can interbreed and produce fertile offspring.. POPULATION. A mechanism for change in populations.. Any change in the . inherited . traits within a population across generations. Individuals better adapted to their environment tend to survive and . produce more offspring. Question? . Is the unit of evolution the . individual. or the . population?. Answer = while evolution effects individuals, it can only be tracked through time by looking at populations. So what do we study? . Question? . Is the unit of evolution the . individual. or the . population?. Answer = while evolution effects individuals, it can only be tracked through time by looking at populations. So what do we study? . Individuals do not evolve, populations do…Darwin. Lynn English High School Science. Biology/Ms. Mezzetti. Population Genetics and Speciation. Genetic Equilibrium. Genetic Variation. Population genetics is the study of evolution from a genetic point of view. Vestigial Structures. DNA & The Genetic Code. Fossil Record. Strata & Superposition. Relative Age vs. Absolute Age. Fossil Record. Per the theory - You would expect older rock to contain mostly organisms that are less complex and less like current (living) organisms. Chapter 22 – Descent with Modification. The Era of Evolutionary Biology. On November 24, 1859, . Charles Darwin. . published his hypothesis in . On the Origin of Species by Means of Natural Selection. Change in . allele frequencies . in a population over generations. Microevolution. Speciation. = origin of species. Microevolution. : changes . in allele frequencies within . a single gene pool. Macroevolution. Chapter 11 Biology Textbook. KEY CONCEPT . Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve.. . Hardy-Weinberg equilibrium describes populations that are not evolving. . What is . Biodiversity. ?. It is the variety of earth’s species, the genes they contain, the ecosystems in which they live, and the ecosystems processes such as energy flow and nutrient cycling that sustain all life..