Lesson Overview Lesson Overview Darwin’s Voyage of Discovery Daily Review #2 3.What were Larmark and Malthus’s theories that impacted Darwin’s thinking? 4.What is artificial selection?

Lesson Overview Lesson Overview Darwin’s Voyage of Discovery On the Origin of Species Knew it was a radical idea Hesitated publishing Wallace – 1858 – To be published essay – Similar ideas Lead to publication in 1859

Lesson Overview Lesson Overview Darwin’s Voyage of Discovery Natural Selection Natural acts like artificial selection Struggle for existence Variation – Natural genetic variation – Some better for that environment – Passed on to offspring – Born with adaptations….organisms don’t adapt, have adaptations Survival of the fittest – Fitness – Adaptations effect fitness – High fitness = survival = reproduction = offspring with same adaptation

Lesson Overview Lesson Overview Darwin’s Voyage of Discovery

Lesson Overview Lesson Overview Darwin’s Voyage of Discovery Big Picture – Natural selection is a mechanism – Organisms better suited leave more offspring – Environment influences fitness – Continual change due to environment changing – Change not in predetermined direction

Lesson Overview Lesson Overview Darwin’s Voyage of Discovery Common Descent Adaptations eventually create new species Descent with modification – Living species share common ancestor Ancestor is different from all existing species Old age of Earth Drew a tree to show possible relationship

Lesson Overview Lesson Overview Darwin’s Voyage of Discovery

Lesson Overview Lesson Overview Darwin’s Voyage of Discovery With what we have talked about so far in this unit, what question(s) do you have?

Lesson Overview Lesson Overview Darwin’s Voyage of Discovery Daily Review #3 5.What is natural selection? 6.What is the difference between variation and adaptation? 7.Give an example of survival of the fittest.

Lesson Overview Lesson Overview Darwin’s Voyage of Discovery Darwin’s Evidence Biogeography – Patterns of distribution between living species and ancestors – Closely related but different Natural selection acts on separate populations Explains Galapagos Island organisms – Distantly related but similar Similar habitats = similar species Similar environment leads to similar adaptations being better suited

Lesson Overview Lesson Overview Darwin’s Voyage of Discovery Age of Earth More accurate age – 4.5 billion years – Radioactive dating of rocks Fossils – Give more ancestors to compare with living species – Many more discovered since Darwin – Fossil record still incomplete

Lesson Overview Lesson Overview Darwin’s Voyage of Discovery Comparing Anatomy Homologous structures – Definition – Darwin’s conclusion – Study Anatomical details Development in embryos – Determine how recently shared ancestor

Lesson Overview Lesson Overview Darwin’s Voyage of Discovery Analogous structures – Share function but not structure – Example Vestigial structures – Homologous structures – Reduced in size – Examples – Still present because don’t reduce fitness

Lesson Overview Lesson Overview Darwin’s Voyage of Discovery Embryology – Developmental stages look similar – Groups of cells become similar things – Common ancestor evidence