Objectives Section 1 Early Ideas About Evolution Contrast the pre-darwin world view w/ the post-darwin world view Examine early ideas about evolution.
Section 1 Science Before Darwin God created man in his own image, in the image of God he created him; male and female he created them. (Genesis 1:27)
Section 1 Contrast of World Views Pre-Darwin World View Post- Darwin World View 1) Earth is only a few thousands years old. Earth is old (a few billions years old). 2) Each species is specially created. Species DON T change. Species CHANGE and are related by descent.
Section 1 3) Adaptation to the environment is God s work. Any variations are imperfections. Adaptation to the environment is the interplay between environmental conditions and genetic variations.
Section 1 God created life all species are the way they were originally created (unchanging over time). But the fossils indicate changes.
Section 1
Section 1 Evolution is the process of biological CHANGE by which descendants come to differ from their ancestors Before Darwin, there were scientists who believed that species evolve.
Section 1 Carolus Linnaeus rejected the notion that organisms were fixed and unchanging Georges Buffon proposed that: species shared ancestors instead of arising separately Earth was a lot more than 6,000 years old
Section 1 Erasmus Darwin all living things descended from a common ancestor More complex life forms arise from less complex Jean Baptiste Larmarck 1) Over a lifetime, physical features increase in size because of use or reduce in size because of lack of use. 2) These changes are passed on to offspring.
Section 1
Section 2 Darwin s Observations Charles Darwin
Section 2 Darwin and Evolution Charles Darwin (1809-1882) A naturalist Made observations that led him to think that species go through a process of change.
Section 2 Artificial Selection
Section 2
Section 2
Section 2 Giant Ground Sloth Three-toed Sloth
Section 2 Capybara
Section 2 Marsupial and Gray wolves
Section 2
Section 2 Galápagos Islands
Section 2 Iguanas
Section 2 Darwin s Voyage
Section 1 Galápagos Islands Giant Tortoises
Section 2
Section 2 Galápagos Finches
The Finches of Galápagos Section 2 Observations The Galápagos finches: - resemble those of South America (Warbler finch) - have different beak shapes and diets (insects, cactus nectar, seeds, etc.) Explanation Their ancestors migrated from South America long ago and changed (or evolved ) over time to adapt to the new environment. But how did evolution take place?
Malthus & Struggle for Existence Section 2 Thomas Malthus human populations are limited by the environment s carrying capacity. In other words, NOT everyone will make it!
Fitness
Fitness Section 2 If NOT everybody will make it, who will? Only the individuals who are able to adapt to a given environment will make it (survive) and reproduce.
4 Principles of Theory of Natural Selection Section 2 1. Overproduction 2. Variation 3. Adaptation 4. Descent with modification
Section 2 OVERPRODUCTION VARIATION
Section 2 ADAPTATION DESCENT WITH MODIFICATION
Section 2 Evolution by Natural Selection Individuals with traits that help them to adapt to their environment are more likely to survive and reproduce than those that do not.
Chapter 13 Section 1 The Theory of Evolution by Natural Selection Adaptation An adaptation is a trait that helps an organism be more suited to its environment.
Section 4 Evidence of Evolution Objectives Describe how the fossil record supports evolution. Infer on how comparative anatomy and development of living species provides evidence of evolution. Summarize how proteins and DNA are used as evidence of evolution. Summarize the process of species formation.
Section 4 The Fossil Record Fossils (impressions onto shale, organisms trapped in amber) are at least 10,000 yrs old Fossils show succession of life forms over time. Ex: Fossil Archaeopteryx is an intermediate between reptiles and birds
Section 4 Reptilian features: jaws w/ teeth and long, jointed tail Bird features: feathers and wings
Section 4 The fossils indicate the following line of descent: Fish amphibian reptile bird mammal
Section 4 Fossil Record Evidence of Whale Evolution
Section 4 Comparative Anatomy
Section 4 All vertebrate forelimbs contain the same sets of bones organized in similar ways despite their different functions. Explanation?
Homologous Structures Section 4 Basic forelimb plan originated with a common ancestor and modified along the way
Section 4 Another example Whales and hummingbirds have skeletons inherited from a common ancestor.
Section 4 Analogous Structures serve the same function in different species but is NOT derived from a common ancestor
Section 4 Homology vs. Analogy Homology = similarity due to common ancestry Analogy = similarity due to convergent evolution
Vestigial Structures Section 4 Vestigial structures: certain bones are reduced in size and have become leftover structures. Ex: Hind leg bone in whales Ex: Leg bone in snakes
Section 4
Section 4 Comparing Embryonic Development
Comparative Embryonic Development Section 4 At some time in their development, all vertebrate embryos have a tail, buds that become limbs, and gill slits. The tail remains in most adult vertebrates. Only adult fish and immature amphibians retain gill slits.
Section 4 Protein (Hemoglobin) Comparison Species descended from a recent common ancestor should have fewer amino acid differences between their proteins than do species that shared a common ancestor in the distant past.
Section 4
Formation of New Species Section 4 Divergence: related species evolve to differ from each other Ex: penguins and owls Convergence: non-related species evolve to resemble each other Ex: marsupial wolf and gray wolf Speciation: the process by which new species form. Over time, populations of the same species that differ genetically because of adaptations to different living conditions become subspecies.
Section 4 Misconceptions Fitness does NOT refer to strength rather about producing the most offspring Organisms do NOT develop certain traits because they need them (Larmarck). There is no such thing as genetic perfection.