PPT-5.5 Variation and Evolution

What is variation Define Variation What controls variation in a population Most characteristics are controlled by multiple genes Any character that shows a gradation from one extreme found in the population to the other is called . Genetic Variation- the raw material for evolution. Evolution. A change in allele frequencies across generations. Evolution. A change in allele frequencies across generations. Selection. Genetic Drift. Basic Forces (what is needed for an evolvable system). Evolution – Basic Forces. Self-replication - reproduction. Heritability - a system by which characteristics can be passed from one generation to the next (here on Earth, DNA is that system). . B. razil. W. el. l. . li. t. an. d . low-nu. t. rient . habitat. Stic. k. y. . underg. r. ound leaves. Eat. s . worms!. P. ereir. a. e. t. . al. . 2012. Th. e. . Pl. a. n. t. o. f. th. e. . D. Keywords: . B1 Topic 1 Classification, Variation and Inheritance. This topic looks at:. General characteristics of animals and plants. Problems surrounding classification. Adaptations of organisms that can survive in extreme environments. Lifeforms. Introduction to Unit. Vocab. for 8.L.4.2. Powell – 8. th. Grade Science. Watch:. “Isn’t Evolution Just a Theory?”. http://www.pbs.org/wgbh/evolution/educators/teachstuds/. svideos.html. 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. Define the term variation.. Discuss the fact that variation occurs within, as well as between, species.. Describe the differences between continuous and discontinuous variation, using examples of a range of characteristics found in plants, animals and other organisms.. Evidence from around the world, experimentation, geology, fossils, discussion with other scientists (Alfred Wallace) lead to:. Theory of evolution . (Biology only). Charles. Darwin ‘On the Origin of the Species’ (1859). Unit:09. Lesson: 01. Be prepared to share your response to the following:. Biological evolution happens at the __________ level, not the individual organism level.. All three definitions mention genetic changes or changes in allele frequency within a population from one generation to the next.. Early scientists proposed ideas about evolution. . Evolution is the biological change process by which descendants come to differ from their ancestors.. A species is a group of organisms that can reproduce and have fertile offspring.. Sexual and asexual reproduction. Reproduction. advantages/disadvantages. Sexual. Asexual. Needs two parents.. Only one parent needed (quicker).. Produces variation in the offspring.. Identical offspring (no variation).. Human variation: defined . Human variation refers to the fact that there are a range of possible values for each of the numerous physical characteristics of human beings.. People of the same species can have differing phenotypic traits that can be related to:. Unit 1 – Microbial life. Unit 1 – Microbial life. Unit 2 – Animal biology. Unit 2 – Animal biology. Unit 2 – Animal biology. Unit 3 – Plant biology. Early life on Earth. Respiration & diffusion. . Fossils provide a record of evolution. . Paleontology is the study of fossils or extinct organisms.. Paleontology provides evidence to support evolution.. Molecular and genetic evidence support fossil and anatomical evidence. .