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Ms. Luaces Evolution

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Quick Review: Theory vs. Law Theory: A well-tested explanation to make accurate predictions They can be changed! Law: A generalized way of explaining things, but doesnt necessarily say why Law of gravity Cant be disproven

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Earths Early History 19.3 What do scientists hypothesize about early Earth and the origin of life? What theory explains the origin of eukaryotic cells? What is the evolutionary significance of sexual reproduction?

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The Mysteries of Lifes Origins Earth was struck by a large object and heated Eventually cooled down enough to form oceans Its atmosphere had very little oxygen

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The Mysteries of Lifes Origins Miller and Ureys experiment suggested how mixtures of organic compounds necessary for life could have arisen Not entirely accurate more recent experiments have been done First formations were thought to be proteinoid microspheres that had some characteristics of living things NOT CELLS!

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The Mysteries of Lifes Origins RNA World hypothesis states that RNA came before DNA do you think this is possible?

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The Mysteries of Lifes Origins First forms of live evolved to live in an oxygen free world anaerobic prokaryotes Eventually, photosynthetic bacteria came around which produced _________. This allowed aerobic organisms to evolve.

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Origin of Eukaryotic Cells EukaryoticProkaryotic Have nucleus Have membrane-bound organelles Have mitochondria No nucleus Very few membrane-bound organelles

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Origin of Eukaryotic Cells The endosymbiosis theory suggests that a __________ relationship evolved between eukaryotes and prokaryotes Created the mitochondria and the chloroplasts we know today

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Origin of Eukaryotic Cells In support of this hypothesis: Mitochondria and chloroplasts contain their own DNA which is similar to bacteria DNA. Have their own ribosomes Replicate like bacteria (binary fission)

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Sexual Reproduction Important in our evolutionary history because it introduces genetic diversity / variation. Genetic variation increases the likelihood of a population adapting to new or changing environmental conditions.

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Evidence of Evolution 16.4 How does the geographic distribution of species today relate to their evolutionary history? How do fossils help to document the descent of modern species from ancient ancestors? What do homologous structures and similarities in embryonic development suggest about the process of evolutionary change? How can molecular biology be used to trace the process of evolution? What does recent research on the Galapagos finches show about natural selection?

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Evidence of Evolution Darwin hypothesized that animals evolved because of natural selection what is that??

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Biogeography Patterns in the distribution of living and fossil species tell us how modern organisms evolved from their ancestors.

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Biogeography Closely related but differentDistantly related but similar Alike species with different traits Different species with same traits (similar environment)

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Age of Earth & Fossils Radioactive data shows Earth to be 4.5 billion years old supporting Darwins theory (lots of time for evolution) Recent fossil records are filling the gaps, showing that modern species evolved from extinct ancestors.

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Comparing Anatomy & Embryology Evolutionary theory explains the existence of homologous structures adapted to different purposes as the result of descent with modification from a common ancestor.

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Comparing Anatomy & Physiology HomologousAnalogous Similar structure Similar function

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Comparing Anatomy & Embryology Vestigial structures arent necessary, but dont harm the function of the organism and so they remain Appendix!

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Comparing Anatomy & Embryology Similar patterns of embryological development provide further evidence that organisms have descended from a common ancestor.

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Genetics & Molecular Biology At the molecular level, the universal genetic code and homologous molecules provide evidence of common descent Most of the DNA and RNA used from bacteria to humans is the same. We must have come from a common ancestor!

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Genetics & Molecular Biology Homologous proteins are shared from bacteria to humans how we make insulin from bacteria for our use. Homologous genes exist between flies and humans these same genes direct our head-to-tail development and limbs

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Testing Natural Selection The Grants were able to test Darwins hypothesis by: Analyze that there was enough heritable variation in the traits for natural selection There were enough differences in beak size and shape to produce differences in fitness

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Testing Natural Selection Dry weather = more survival of large beak birds Their data confirmed that competition and environment drive natural selection

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Hominine Evolution 26.3 (Pg. 767) What adaptations enabled later hominine species to walk upright? What is the current scientific thinking about the genus Homo?

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Hominine Evolution We separated to create hominines and chimpanzees The skull, neck, spinal column, hip bones, and leg bones of early hominine species changed shape in ways that enabled later species to walk upright bipedal.

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Hominine Evolution Bipedal allowed us to free our hands for tools developed opposable thumbs Also developed larger brains (cerebrums) Figure 26-16 gives major differences between humans and gorrillas

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Hominine Evolution Fossils date back to 7 million years old not all findings are ancestors, they may be relatives Research suggests bipedalism evolved before larger brains Oldest hominine: 2002, Sahelanthropus Best studied:1974, Australopithecus afarensis or Lucy

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Hominine Evolution Recent research shows our human evolution isnt straight forward more like several branches and several trunks Homo habilis: handy man, probably our ancestor Homo ergaster: bigger brain, downward-facing nostrils

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Hominine Evolution Our genus originated in Africa and migrated from there to populate the world Homo habilis in Turkey Homo Erectus in Asia

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Hominine Evolution Multiregional hypothesis says we evolved independently in various parts of the world Out-of-Africa model suggests we migrated and colonized the rest of the world about 200,000 years ago More supported theory by mitochondrial DNA evidence

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Hominine Evolution Modern humans may or may not have coexisted with Neanderthals something made Neanderthals go extinct and Homo sapiens remain the only hominine clade. Both used stone tools, lived in complex social groups, controlled fire, and had rituals to bury their dead.

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GO HEAT!!

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The Brain (Pg. 902-903) Split into 5 major components: Cerebrum Limbic System Thalamus and Hypothalamus Cerebellum Brain Stem

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The Brain Cerebrum: largest region of the brain responsible for voluntary (conscious) activities Intelligence, learning and judgment are stored here The part that grew the most in our ancestors

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The Brain The Cerebrum is split up into right and left hemispheres Left hemisphere controls right-side of the body and vice versa Also into four lobes Frontal (planning, judgments) Temporal (hearing and smell) Parietal (reading and speech) Occipital (vision)

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The Brain The Cerebrum also has two layers The cerebral cortex (topmost layer, aka grey matter) which has many of the neurons responsible for all the activities White matter (innermost layer) which makes connections between different brain areas

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The Brain Limbic System: mostly associated with emotions, behavior, and long-term memory

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The Brain Thalamus: receives messages from sensory neurons and sends them to the right place Hypothalamus: helps to know and analyze hunger, thirst, fatigue, anger, and body temperature

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The Brain Cerebellum: second largest region of the brain which deals with coordinating the bodys actions

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The Brain Brain stem: the oldest part of the brain which connects the brain to the rest of the body Also controls important functions like blood pressure, heart rate, breathing, and swallowing What keeps you breathing while you sleep

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Darwins Voyage of Discovery 16.1 Darwin developed a scientific theory of biological evolution that explains how modern organisms evolved over long periods of time through descent from common ancestors Darwin was born in 1809 and began his journey in 1831 on the HMS Beagle

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Observations Aboard The Beagle Darwin didnt just observe species, he thought about them in scientific ways and noticed Species vary globally Species vary locally Species vary over time Different species inhabit separate, but ecologically similar habitats

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Observations Aboard The Beagle Darwin also noticed that different, yet related animal species occupied different habitats within a local area All his observations were conducted between Australia, South America, and Africa (and of course, the Galapagos)

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Observations Aboard The Beagle Darwin also noticed that some fossils of extinct animals were similar to living species the Glyptodont and the Armadillo All of this evidence suggested that species are not fixed, but that they change by some kind of natural process which we know today as ________________.

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Lets Practice! Find your study buddy Study Workbook A Pgs. 169-170. Question AND Answer. One sheet of paper for both of you Skip #4

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Ideas that shaped Darwins thinking 16.2 Hutton and Lyell, two geologists, concluded that Earth is extremely old and the processes that changed Earth in the past are still operating in the present Went against the idea that Earth was only a few thousand years old

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An Ancient, Changing Earth Hutton introduced deep time: our planets history is older than we can imagine. He reached this conclusion by his observations of: The layers of rocks in mountains, valleys, and even volcanic molten lava Rain, wind, heat and cold take a long time to shape rock

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An Ancient, Changing Earth Lyell believed in uniformitarianism laws are constant over time (what happens now, happened then) Darwin read Lyells book and observed an earthquake push rock from the sea out if Earth was old, and the same things happened, could life have changed too?

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Lamarcks Evolutionary Hypothesis Lamarck suggested that species decide what part of themselves to use / not use, and these traits were passed on to offspring Published the year Darwin was born, 1809

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Lamarcks Evolutionary Hypothesis He suggested that if we wanted longer legs, we simply had to wish or stretch for them and it would happen acquired characteristics Then, we passed then on to our children inherited acquired characteristics Crazy ideas! But he was the first to suggest we changed according to our environment essential for people like Darwin to come up with evidence!

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Population Growth Malthus had suggested that we cant grow unchecked because there wont be enough space for everyone we were limited by war, famine and disease Darwin linked this to other organisms and reasoned this must be the reason why only certain individuals survive and reproduce

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Artificial Selection Variations cause some animals to be more productive than others we choose the best and breed those to make sure those variations become permanent. Darwin didnt understand where these variations came from, but he knew this would cause changes in the species

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Darwin Presents His Case- 16.3 Darwin did not publish his ideas immediately for fear of being ridiculed, until he found out Wallace was about to publish something very similar

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Evolution by Natural Selection The struggle for existence: more are born than can survive, and must compete for resources Those with the best adaptations (body part, color, function or behavior) survive and reproduce have high fitness

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Evolution by Natural Selection Natural selection occurs in any situation in which More individuals are born that can survive (survival of the fittest) There is natural heritable variation (variation and adaptation) There is variable fitness among individuals (survival of the fittest)

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Evolution by Natural Selection Natural selection doesnt make perfect organisms- just good enough to survive in their environments If the environment changes, adaptations can change also so long as its not too fast of a change

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Common Descent As generations progress, we get species evolving into new species descent with modification The principle of common descent is that all living and extinct species are descended from ancient common ancestors The tree of life