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Evolution. Descent with Modification: A Darwinian View of Life. Evolution Defined . Evolution : gradual hereditary changes in groups of living organisms over time. . November 24, 1859. Lamarck’s Theory. Jean Baptiste de Lamarck , 1809
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Evolution Descent with Modification: A Darwinian View of Life
Evolution Defined Evolution: gradual hereditary changes in groups of living organisms over time. November 24, 1859
Lamarck’s Theory • Jean Baptiste de Lamarck, 1809 • First theory of evolution- how species change
Lamarck’s Theory • **Inheritance of acquired characteristics-The changes acquired during an animals lifetime from use and disuse may be passed on to its offspring. • Law of use and disuse-parts used by animal become stronger, parts used less become weaker
Charles Darwin • Father of Evolution • Developed the theory of evolution after his trip on the H.M.S Beagle • Published the Origin of Species on November 24,1859
The finches beaks were different based on the type of food they ate.
Keep in mind…… • Populations or species evolve, not individuals
Major pieces of Evidence for Evolution • Fossils • Comparative Anatomy (homologous structures) • Selective Breeding of Animals and Plants
1. Fossil Evidence Fossils: remains and traces left behind by organisms -most direct evidence for evolution -provides a record of ancient organisms that have existed -able to generate a timeline -ancestral descent and lineages can be generated Types of Fossils: imprints, hair, nails, tissue, and other remains Locations: sedimentary rock, ice, amber, tar, quicksand, petrification
Evidence: 1. The Fossil Record • Shows succession of forms over time • Transitional links • Vertebrate descent
Evolution Evidence: 2. Comparative Anatomy Homologous Structures Types of Structures: • A. Homologous structures (same structure, diff. use) • Shows possible descent from a common ancestor
6. Selective Breeding • We have bred various animals and plants for specific purposes, selecting the traits WE want them to acquire. • The process in which humans select which plants or animals to reproduce based on certain desired traits is called selective breeding. • Ex- horses, dogs, strawberries, corn • This is controlled evolution.
Darwin’s Theory • Variation- There is a natural variation in any population. Every individual has its own combination of traits. • Overproduction- more offspring are born than survive. 3. Struggle to Survive- members of a species compete for food, habitat, etc. (limits population) 4. Reproduction- individuals that are best adapted to their environment are likely to have many offspring that survive. Natural selection- “survival of the fittest”- The species most fit for their environment will survive to pass on their traits.
Darwin’s Theory of Natural SelectionWhat Is Natural Selection? Darwin proposed the theory that evolution happens through a process that he called natural selection. Individuals that are betteradapted to their environment survive and reproduce more successfully than less well adapted individuals.
7. Examples of Natural Selection • Peppered moth • antibiotic resistance
Examples of Modern (Recent) Evolution • Peppered Moth- during day sits on tree trunk. More active at night. • Before 1850 tree trunks were light in color, and most moths were gray. • After 1850 (industrial revolution), the predominant color of moth was black, which matched the soot on the trees. peppered moth activity
Key Points to Remember • A population evolves not an individual organism • The accumulation of small changes over long periods of time results in larger changes • A new species emerges with slightly different characteristics usually because of being isolated. • How and why organisms are able to transmit heritable traits to the next generation was not explained by Darwin. • Common Ancestry!
Final words…... • “Absence of evidence is not evidence of absence.”