1. Evolution and Natural Selection Change over time…

2. Origins of Life on Earth Fig. 4-2, p. 84 Variety of multicellular organisms form, first in the seas and later on land ___________ __________ (3.7 billion years) _________ ___________ (1 billion years) Formation of the earth’s early crust and atmosphere Small organic molecules form in the seas Large organic molecules (biopolymers) form in the seas First protocells form in the seas Single-cell prokaryotes form in the seas Single-cell eukaryotes form in the seas

4. Jean Baptiste Lamarck Lamarck was in charge of the invertebrate collection in a Paris museum; he spent his time there comparing the fossils in the collection Lamarck was in charge of the invertebrate collection in a Paris museum; he spent his time there comparing the fossils in the collection In 1809, he proposed that organisms evolve into more and more complex forms through ______________________________ ______________________________ ______________________________ In 1809, he proposed that organisms evolve into more and more complex forms through ______________________________ ______________________________ ______________________________ Essentially, Lamarck believed that organisms constantly strive to improve. This effort to improve causes the most used body structures to develop, while the “unused” structures disappear. These modifications are then passed on to offspring Essentially, Lamarck believed that organisms constantly strive to improve. This effort to improve causes the most used body structures to develop, while the “unused” structures disappear. These modifications are then passed on to offspring Lamarck’s theory is ______accepted by scientists today! Lamarck’s theory is ______accepted by scientists today!

5. Charles Darwin and the Beagle? In 1831, at the very young age of 21, Charles Darwin took a job as a _________on a British ship known as the H.M.S. Beagle In 1831, at the very young age of 21, Charles Darwin took a job as a _________on a British ship known as the H.M.S. Beagle On this five-year journey through the South Pacific, Darwin studied and collected many different organisms On this five-year journey through the South Pacific, Darwin studied and collected many different organisms When Darwin reached the___________ ________, he was very intrigued by the odd variety of species he saw there… When Darwin reached the___________ ________, he was very intrigued by the odd variety of species he saw there…

6. The Galapagos Islands This small group of islands is home to many unique creatures, such as the giant tortoise, large marine iguanas, and a flightless bird known as a cormorant In particular, Darwin noticed that there were many varieties of________. Each variety was similar to the finch species he had seen on the mainland of South America, yet each was specially adapted to its _____________ in a unique way _________________= Any inherited characteristic or behavior that helps an organism better survive in its environment (e.g., camouflage, mimicry, etc.)

7. The Origin of Species When Darwin returned to England, he wasn’t sure how to explain what he had observed; he spent many years conducting additional experiments and discussing his ideas with others When Darwin returned to England, he wasn’t sure how to explain what he had observed; he spent many years conducting additional experiments and discussing his ideas with others In 1859, Darwin published his groundbreaking book, The Origin of Species By Means of Natural Selection, to explain his theory In 1859, Darwin published his groundbreaking book, The Origin of Species By Means of Natural Selection, to explain his theory In this book, Darwin proposed that evolution happens through a mechanism called_____________ ___________________________ In this book, Darwin proposed that evolution happens through a mechanism called_____________ ___________________________

8. Natural Selection Darwin proposed that a process he called Natural Selection causes species to change over time 1. Organisms produce more offspring than can survive, which causes competition for resources(food, water, shelter, mates, etc) 2. ____________________________ 3. Some variations help the organism better survive in its environment. These organisms are ______ _______to survive and reproduce, passing their genes on to the next generation 4. Over time, there will be more and more individuals in the population with the favorable trait. So, the whole population gradually changes (EVOLVES) over time to become better adapted to its environment.

9. Evidence for Evolution Darwin’s Theory is supported by many different types of scientific evidence, such as: Darwin’s Theory is supported by many different types of scientific evidence, such as: Fossils clearly show that many species have changed over time; some fossils show transitional forms (intermediate species between the old and new species) Fossils clearly show that many species have changed over time; some fossils show transitional forms (intermediate species between the old and new species)

10. More Evidence for Evolution ___________ ___________– many species with common ancestry show similar structures. For instance, the forelimbs of many mammals show similar bone structure, implying that there are all modified versions of structures that occurred in a common ancestor __________ ____________ – unrelated species living in similar habitats often have similar structures that serve the same function, such as the fins of a dolphin and a shark _________ ___________ – many species have body parts that no longer serve any useful purpose, like the pelvic bones of a whale, or your appendix _______ ____________– Today, similarities in DNA and amino acid sequences show how species may be related. For example, humans and chimpanzees (our closest living relative) share over 98% of our DNA

11. Microevolution Population Genetics – species (NOT individuals) evolve because of genetic changes in the _____ _____ Population Genetics – species (NOT individuals) evolve because of genetic changes in the _____ _____ Evolution occurs when the gene frequency (how often a certain gene is found in a population) changes and the population is no longer in genetic equilibrium (known as the HARDY- WEINBERG principle) Evolution occurs when the gene frequency (how often a certain gene is found in a population) changes and the population is no longer in genetic equilibrium (known as the HARDY- WEINBERG principle) What disrupts genetic equilibrium? 1. _______ _______-changes in a SMALL population due to chance events (e.g. natural disasters) 2. ____ _____-movement of genes in/out of a population 3. _________- add new genes to the gene pool 4. _______ _________-has the greatest effect on the population

12. Types of Natural Selction ___________ selection- selects the average individual and gets rid of the extremes ____________ selection-selects for ONE of the extreme traits -Sexual selection-female of the species often selects her mate based on certain characteristics (such as the very large, bright feathers of the peacock) __________ Selection – selects for two extremes, gets rid of the average trait (also called diversifying selection)

13. Speciation Eventually, natural selection may cause two groups of organisms to become so genetically different that they can no longer interbreed and produce fertile offspring Eventually, natural selection may cause two groups of organisms to become so genetically different that they can no longer interbreed and produce fertile offspring Therefore, these two groups are considered to be two different______________ Therefore, these two groups are considered to be two different______________ The evolution of new species = ________________________(Macroevolution) The evolution of new species = ________________________(Macroevolution)

14. Isolation Speciation often begins when two groups become isolated Speciation often begins when two groups become isolated 1. ____________ isolation-a physical barrier separates 2 groups, such as a body of water, mountain range, highway, etc.) 2. ______________ isolation- occurs when 2 groups cannot reproduce together; sometimes caused by geographic isolation, but can also occur because of a change in behavior

15. Geologic Processes, Climate Change, and Catastrophes ________ ________, such as the movement of tectonic plates, formation of mountain ranges, or volcanic eruptions can sometimes isolate populations, leading to evolution ________ ________, such as the movement of tectonic plates, formation of mountain ranges, or volcanic eruptions can sometimes isolate populations, leading to evolution _______ _______can also drive evolution by determining where populations of plants and animals can survive _______ _______can also drive evolution by determining where populations of plants and animals can survive Other catastrophes and natural disasters, such as asteroids or floods can isolate populations and drive evolution Other catastrophes and natural disasters, such as asteroids or floods can isolate populations and drive evolution

16. Patterns of Evolution… Isolation and natural selection can lead to different types of evolution: -___________ Evolution- distantly related organisms become more similar over time due to similar habitats

17. …Patterns of Evolution -__________ Evolution-one species eventually diverges into two or more new species, becoming increasingly different over time in response to different environments -Adaptive Radiation-type of divergent evolution in which one ancestral species gives rise to a wide variety of new, different species (Darwin’s finches)

18. How fast is evolution? Usually, evolution is considered to be a slow, gradual process that continuously operates over many generations (_____________________) However, the fossil record also shows time periods of very rapid speciation, during which many new species arose all at once, with long periods of equilibrium in between these “bursts” (___________ __________)

19. How does evolution affect ecosystems? Evolution often leads to the development of species that occupy a variety of ___________within a habitat Each species has a distinct role to play in the ecosystem Some species may be considered GENERALISTS (occupy a broad niche), while others are SPECIALISTS (occupy a small niche)

20. Biodiversity Evolution usually leads to increased____________________ Increased biodiversity strengthens an ecosystem by increasing the “connections” in the food web and making it less susceptible to disease If species can not evolve quickly enough, evolution may lead to ___________________________ Speciation-Extinction=Biodiversity There have been five _____ _____________throughout history Are humans currently causing the next mass extinction?