Evidence of Evolution 4 Types

1. Q2 Week 1 Evidence of Evolution

2. OUTCOME: Identify and explain 4 different types of evidence used to support Darwin’s Theory of Evolution through Natural Selection. 1 2 Science Starter Evolution Introduction The Daily Scoop Mystery Animal??? Video clip 3 4 Evidence for Evolution Close Read Independent Practice Slide Exploration HW: Comic Book Reflection

4. What if I told you this is a picture of an ancient ancestor of a modern day animal - can you guess the modern day relative? Pop your quess in the Chat!!

5. It’s a….. Walking Whales?? Let’s take a closer look… Video https://www.pbs.org/video/walking-whale-ancestor-mcwibo/

6. How in the world did whales go from walking on four legs to living in the ocean?!?! Let’s begin by looking at the evidence….

7. Mesonychids were the first mammaliancarnivores after the extinction of the dinosaurs. They had an elongated skull and triangular teeth, which are similar to whales. These creatures also had an inner ear, which is a characteristic feature of whales. They lived 60 million years ago. Indohyus is a small deer-like creature, which lived about 49 or 48 million years ago in Kashmir, India. This raccoon size herbivorous creature shared some of the traits of whales. It also showed signs of adaptations to aquatic life, including a thick and heavy outer bone coating. This is similar to the bones of modern creatures such as the hippopotamus, and reduces buoyancy so that they can stay underwater.

8. Pakicetus is a genus of extinct cetaceans (marine mammals) found in Pakistan 55.8 - 33.9 million years ago. The first fossil, a lone skull, had characteristics of the inner ear which are found only in cetaceans: the large auditory bulla is formed from the ectotympanic bone only. This suggests that it is a transitional species between extinct land mammals and modern cetaceans. Ambulocetus ("walking whale") was an early amphibiouscetacean. It could walk as well as swim. They lived from (50 to 48 million years ago). It looked like a 3-meter (10-foot) long mammaliancrocodile. It was clearly amphibious: its back legs are better adapted for swimming than for walking on land, and it probably swam by undulating its back vertically, as otters and whales do. Scientists consider Ambulocetus to be an early whale because it shares underwater adaptations with them. It had an adaptation in the nose that enabled it to swallow underwater, and its periotic bones had a structure like those of whales, enabling it to hear well underwater. Also, its teeth are similar to those of early cetaceans.

9. Basilosaurus is a genus of cetacean that lived from 40 to 34 million years ago. The first fossil was discovered in the United States and was initially believed to be some sort of reptile but it was later found to be a marine mammal.Far from being a marine reptile, Basilosaurus is a stage in the evolution of whales. At 15–20 m (49–66 ft), Basilosaurus was one of the largest oceanic animals of its time. Basilosaurus went extinct during the Eocene Extinction. Cetaceans are marinemammals that live in oceans, seas, and even a few rivers around the world. Whales, dolphins, and porpoises are part of this group. These common name refer to size: whales are the largest, porpoises the smallest. How and what they eat is a better guide to their relationships. The study of cetaceans is called cetology. Cetaceans are ocean creatures without toes, but are classified in the related order Cetartiodactyla because their ancestors were even toed ungulates.

10. Fifty-two million years ago a wolf sized carnivore ate his last meal on the shore of an ancient ocean. Waves washed sediment over the creature’s decaying body preserving its skull. Millions of years past and slowly the Earth changed. Tectonic plates shifted and the once bountiful ocean became a barren desert. An Egyptian dynasty of God-Kings came and went. Greek city-states introduced democracy to the world and then lost their freedom to a Macedonian King. Roman rose, built an empire that stretched across three continents, and fell. Yet still the skull remained untouched, buried by the sands of time. That is until paleontologist Dr. Phil Gingerich unearthed the ancient remains while working on a dig in Pakistan. He named the creature Pakicetus. It was a discovery most scientists only dream of, a perfectly preserved and complete skull of a previously unknown creature. The ‘mystery’ skull Pakicetus found by Phil Gingerich

11. With its sharp teeth, elongated jaw and nostrils situated at the tip of the snout, Pakicetus reminded most paleontologists of an ancient wolf-like carnivore called a Creodont. But Gingerich is not so sure. He believes Pakicetus is the ancient terrestrial ancestor of whales, “Pakicetus had a thickened skull bone, called an auditory bulba, which is only found in modern whales.” Fellow paleontologist, Dr. Mathews, is not convinced “There is simply not enough evidence at this point to jump to the conclusion that Pakicetus is related to modern whales.” Artistic representations of two Creodonts Artistic representation of Archaeocetes

12. This is a leaf of the ancient Maidenhair tree (Gingko gardneri) which is related to modern day Gingko Biloba trees. Fossils:the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock. A fossil of a unicorn fish from the Eocene. The unicorn fish have sharp poisonous blades fixed above their nose (like modern day surgeon fish).

13. Evidence for Evolution: 4 Types What evidence do paleontologists use to prove that species change over time? https://docs.google.com/document/d/11hFmqclw8DeKU4FfAaEZGrnJdXPFGj-vzEsEQUJCcvA/edit (Article is posted to next few slides)

14. Evidence for Evolution Homologous Features If two or more species share a unique physical feature, such as a complex bone structure or organ, they may all have inherited this feature from a common ancestor. Physical features shared due to evolutionary history (a common ancestor) are said to be homologous. To give one classic example, the forelimbs of whales, humans, birds, and dogs look pretty different on the outside. That's because they're adapted to function in different environments. However, if you look at the bone structure of the forelimbs, you'll find that the pattern of bones is very similar across species.

15. The developmental patterns of these species become different later on (which is why your embryonic tail is now your tailbone, and your gill slits have turned into your jaw and inner ear). Homologous embryonic structures reflect that the developmental programs of vertebrates are variations on a similar plan that existed in their last common ancestor. Embryology Some homologous structures can be seen only in embryos. For instance, all vertebrate embryos (including humans) have gill slits and a tail during early development.

16. Fossil Record Fossils are the preserved remains of previously living organisms or their traces, dating from the distant past.The fossil record provides snapshots of the past that, when assembled, illustrate a panorama of evolutionary change over the past four billion years. The picture may be smudged in places and may have bits missing, but fossil evidence clearly shows that life is old and has changed over time.

17. Relative Dating Relative Dating is used to determine the relative (not exact) age of fossils. When looking at a strata of rock layers like this one, scientists know that the older rock layers lie below the younger ones. This principal is called The Law of Superposition. Using this principal, we can infer that any fossils found in the lower layers are older than those found in the layers that lie above them. Law of Superposition The age of the Earth and its inhabitants has been determined using two methods: relative dating and absolute dating. Absolute Dating Sedimentary rocks can be dated using the radioactive decay of their carbon content. Using this method, scientists can determine the exact age of the sedimentary rock layer and thus age the fossils they contain. Geologists have assembled a geological time scale based on the rocks and the fossils that have been discovered. The time scale shows 4.6 billion years of Earth’s history!

18. How do we know Evolution Happens? Close Read: Evidence for Evolution

19. Evidence for Evolution • Fossil Record • Superposition • Homologous Structures • Embryology Write your details here!

20. Slide Exploration Directions: • Carefully examine each slide. • As you move from one piece of evidence to the next add detail, key words, examples, labeled diagrams to your notes!

21. 1. Fossil Record • Fossils are the remains or impressions of once-living organisms preserved in rock. Over millions of years, their bodies are compressed by new layers of Earth. This means that older fossils are found in deeper layers, while newer fossils are closer to the surface. • The fossil record is the complete collection of fossils we have. They give us clues as to how the organism lived and looked. There are, however, ”holes” in the fossil record, in which we do have a fossil to help bridge the belief that two species are somehow related. Fossils tell us what lived long before humans inhabited the Earth. Fossils are often called “Secrets in Stone”- because they hold the keys to the past. By examining fossils we can tell what type of organisms lived, when they lived, what they lived with, the environment they lived in and even what they ate!

22. 2. Law of Superposition Ordering of Rock Layers • Scientists read the rock layers knowing that each layer is deposited on top of other layers. • The law of superposition states that each rock layer is older than the one above it. So, the relative age of the rock or fossil in the rock or fossil in the rock is older if it is farther down in the rock layers. • Relative dating can be used only when the rock layers have been preserved in their original sequence. Which rock layer is the oldest? Layer 4 is the oldest Which rock layer is the youngest? Layer 1 is the youngest

23. Examine the diagram. Use the key to complete the following questions. • Which fossil is the oldest? • Which fossil is the youngest? • Suppose a fossilized shell was found in the top rock layer of a mountain. What can scientists infer about that area in the past?

24. Examine the diagram. Use the key to complete the following questions. • Which fossil is the oldest? Trilobite • Which fossil is the youngest? Fern • Suppose a fossilized shell was found in the top rock layer of a mountain. What can scientists infer about that area in the past? This area was once underwater!

25. 3. Homologous Structures Divergent evolution To “diverge” is to take a different path. Divergent evolution is the process by which organisms with shared traits diverge into different variations over time. One of the most evident examples of this process is seen by comparing the front limb in vertebrates. Bat wings, monkey hands, pig legs, and dolphin flippers (to name a few) all share extremely similar structures. This would suggest that they shared a common ancestor, and that the form of each limb has changed over time due to different uses in different environments. Pictured below is both a rendering and actual fossil of the Tiktallik, a fish with strong forelimbs, used to carry it onto land. It is believed to the be the common ancestor of four-limbed animals Homologous structures are body parts with similar structures that have different uses based on different habitats. • Mammals, birds, reptiles and amphibians have the same skeletons, but bones with different proportions. Tiktaalik

26. 3. Homologous Structures A homologous structure does not have to be used for the same purpose in order to show evolutionary relationships. For example, all mammals have the same bones in their arms. A bat uses its arms as wings and a human uses them to hold things but the bone structure is the same. These are homologous structures.

27. 2 4 6 7 3 5 1 Take a look at the homologous features above. What animals do you think they belong to?? Make an educated guess below: 1. 5. 2. 6. 3. 7. 4.

28. 1 2 3 4 5 6 1 2 3 4 5 6 7 Take a look at the homologous features above. What animals do you think they belong to?? Make an educated guess below: 1. Human 5. Bat 2. Lizard 6.Frog 3. Cat 7. Bird 4. Whale How did you do?!?!

29. Embryology is the study of the embryo – an unborn offspring in the process ofdevelopment. Embryos give evidence for evolution because many different kinds of organisms have embryos that look alike, suggesting that they all evolved from a common ancestor millions of years ago. 4. Comparative Embryology

30. Take a Guess! 1 2 3 4 What organisms do they embryos belong to? Take a guess below. 1. 2. 3. 4.

32. Common ancestor – most recent individual from which all the organisms studied are directly descended. • According to evolutionary theory, all life originated from a common ancestor (known as common descent). • If organisms are related, they share a common ancestor. The more related they are, the more features and genetic makeup they share. 3. Comparative Embryology

33. https://www.youtube.com/watch?v=7CnjoCu1154

34. Igneous rocksare formed from melted rock deep inside the Earth. Sedimentary rocks are formed from layers of sand, silt, dead plants, and animal skeletons. Metamorphic rocks formed from other rocks that are changed by heat and pressure underground. https://www.youtube.com/watch?v=EGK1KkLjdQY

36. Some rock examples: https://www.youtube.com/watch?v=TbHB7xUjMIk More info: https://www.youtube.com/watch?v=iNNoNE6udNo

38. Rock Samples: 1. 2. 3. 4. 5. 6. 7. 9. 8.

39. Categorize rocks based on their characteristics as igneous, metamorphic, or sedimentary rocks. Part 1: Investigating Crystal Size

40. Record your predictions in the data table below KEY: S=sedimentary I=igneous M=metamorphic Classify the following rocks as sedimentary, igneous, or metamorphic. Justify your reasoning below each picture. Rock type? Justify: Rock type? Justify: Rock type? Justify:

41. Rock activity answers https://www.amnh.org/explore/ology/earth/if-rocks-could-talk2/three-types-of-rock

42. Plate Tectonics Continental/Continental: The Himalayas Click the image to view the simulation and read about the Himalayan mountain range and Tibetan plateau that have formed as a result of the collision between the Indian Plate and Eurasian Plate. https://www.geolsoc.org.uk/Plate-Tectonics/Chap3-Plate-Margins/Convergent/Continental-Collision

43. The Himalayan mountain range and Tibetan plateau have formed as a result of the collision between the Indian Plate and Eurasian Plate which began 50 million years ago and continues today. 225 million years ago (Ma) India was a large island situated off the Australian coast and separated from Asia by the Tethys Ocean. The supercontinent Pangea began to break up 200 Ma (moving average) and India started a northward drift towards Asia. 80 Ma India was 6,400 km south of the Asian continent but moving towards it at a rate of between 9 and 16 cm per year. At this time Tethys Ocean floor would have been subducting northwards beneath Asia and the plate margin would have been a Convergent oceanic-continental one just like the Andes today. As seen in the animation above not all of the Tethys Ocean floor was completely subducted; most of the thick sediments on the Indian margin of the ocean were scraped off and accreted onto the Eurasian continent in what is known as an accretionary wedge (link to glossary). These scraped-off sediments are what now form the Himalayan mountain range.

44. From about 50-40 Ma the rate of northward drift of the Indian continental plate slowed to around 4-6 cm per year. This slowdown is interpreted to mark the beginning of the collision between the Eurasian and Indian continental plates, the closing of the former Tethys Ocean, and the initiation of Himalayan uplift. The Eurasian plate was partly crumpled and buckled up above the Indian plate but due to their low density/high buoyancy neither continental plate could be subducted. This caused the continental crust to thicken due to folding and faulting by compressional forces pushing up the Himalaya and the Tibetan Plateau. The continental crust here is twice the average thickness at around 75 km. The thickening of the continental crust marked the end of volcanic activity in the region as any magma moving upwards would solidify before it could reach the surface. The Himalayas are still rising by more than 1 cm per year as India continues to move northwards into Asia, which explains the occurrence of shallow focus earthquakes in the region today. However the forces of weathering and erosion are lowering the Himalayas at about the same rate. The Himalayas and Tibetan plateau trend east-west and extend for 2,900 km, reaching the maximum elevation of 8,848 metres (Mount Everest – the highest point on Earth).