1. N ATURAL SELECTION

2. B ELL RINGER Define natural selection Define biological evolution Acquired Trait Define mutation

3. O BJECTIVES : Relate Lamarck to acquired traits and Darwin to natural selection List the principals of natural selection

4. L AMARCK ’ S IDEAS ON EVOLUTION Jean Baptiste Lamarck (1744-1829) French biologists Supported the idea that populations of organisms change over time Thought that simple organisms could arise from nonliving matter

5. L AMARCK ’ S IDEAS ON EVOLUTION Thought that simple organisms inevitably developed into more complex forms Proposed that individuals could acquire traits during their lifetimes as a result of experience or behavior – then passed on the traits to offspring This idea is known as inheritance of acquired traits Acquired traits (or characters) are those changes in the structure or function of an organism that are the result of use, disuse, environmental influences, disease, or mutilation.

6. D ARWIN ’ S IDEA OF EVOLUTION In the mid 1800’s Charles Darwin formed a theory to explain how evolution takes place Darwin was a naturalist on the H.M.S Beagle who sailed to the Galapagos Islands Darwin published a book entitled On the Origin of Species by Means of Natural Selection Darwin used the phrase “descent with modification” to describe the process of evolution

7. D ARWIN ’ S IDEA OF EVOLUTION Darwin saw animals of the Galapagos Islands as evidence Islands are home to 13 similar species of finches – Darwin suspected that all 13 species descended from and diverged from just a few ancestral finches – these finches came from the coast of South America

8. D ARWIN ’ S F INCHES

10. D ARWIN ’ S IDEA OF EVOLUTION Darwin proposed the theory of natural selection as the mechanism for descent with modification Natural selection has four principles: 1. overproduction 2. genetic variation 3. struggle to survive 4. differential reproduction

11. P RINCIPLES OF NATURAL SELECTION 1. overproduction – more offspring can be produced than can survive to maturity Example: in a population of rabbits, female rabbits can produce a large number of offspring – each rabbit requires food and is vulnerable to predators and disease so not all live very long. 2. genetic variation – in a population individuals have different traits – some deer in a population may have longer hair which they pass on to the offspring

12. P RINCIPLES OF NATURAL SELECTION 3. struggle to survive – individuals must compete with each other – some variations improve an individual’s chance to survive A trait makes an individual successful in its environment 4. differential reproduction – organisms with the best adaptations are most likely to survive and reproduce Natural selection is also known as “the survival of the fittest”

14. A RTIFICIAL S ELECTION

16. O BJECTIVES Relate current organisms to past organisms based on the included evidences Cite examples supporting scientific evidence

17. F OSSIL RECORD Fossil is the remains of an organism that died long ago Fossils show that different types of organisms appeared at different times and places on Earth

18. A GE OF FOSSILS 1669, Danish scientist Nicolaus Steno (1638- 1686) proposed the principle of superposition Principle of superposition states that if the rock strata at a location have not been disturbed, the lowest stratum was formed before the strata above it. Geologist put together a timeline for the order in which group of rocks and fossils were formed Time line is known as the geologic time scale Geologists can tell a fossils relative age – age compared to that of other fossils

19. A GE OF FOSSILS Absolute age of rock is determined by radiometric dating Radioactive dating using carbon dating Uses radioactive isotopes to determine the age of fossils – based on half-life of the isotopes By using the relative dating and absolute dating scientist can determine the age of fossils.

20. D ISTRIBUTION OF FOSSILS 1 st we can infer that different organisms lived at different times 2 nd we can infer that today’s organisms are different from those of the past Trilobites were unlike any organism alive today 3 rd we can infer that fossils found in adjacent layers are more like each other than to fossils found in deeper or higher layers 4 th by comparing fossils and rocks from around the planet – we can infer when and where different organisms existed

21. B IOGEOGRAPHY AND ANATOMY AND EMBRYOLOGY Is the study of the locations of organisms around the world Anatomy is the study of body structure of organisms Embryology is the study of how organisms develop Page 305 figure 15-8 Homologous structures – are anatomical structures that occur in different species and that originate by heredity from a structure in the most recent common ancestor

22. B IOGEOGRAPHY AND ANATOMY AND EMBRYOLOGY Analogous structures have closely related functions but do not derive from the same ancestral structure Vestigial structures serve no function but resemble structures with functional roles in related organisms Human tailbone is made of four fused vertebrae that resemble the bones in an animal’s tail

23. B IOLOGICAL MOLECULES Look at the DNA and RNA of organisms – scientists compare the DNA of organisms – the closer related the organisms the closer the DNA samples are