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CH 6.2

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  1. CH 6.2 Species Change Over Time

  2. CH 6 Objectives • Identify early ideas and observations on evolution • Explain how Darwin developed his theory of natural selection • Identify Darwin’s 4 principles of natural selection • Describe how new species can form from previous species

  3. Essential Questions and Understandings • What is evolution and who contributed to the modern theory of evolution? • Compare and Contrast Artificial and Natural Selection • What are Darwin’s 4 principles and how do they lead to evolution? • What is speciation? • How can isolation of a group of individuals lead to a new species?

  4. Evolution • Evolution is defined as change over time • It is the result of changes in the genetic material that are passed from generation to generation • Organisms use adaptations to have a better chance of surviving and reproducing

  5. History • Lamarck was on of the first scientists to suggest the idea of change over the lifetime of an organism (Giraffes Necks) • Darwin studied plant and animal species on the Galapagos Islands (178 islands) • He noticed that species were different from island to island • Looked at adaptations to certain environments • Looked at finches and their feeding behaviors

  6. Artificial Selection • When people (breeders) produce new varieties of animals over time • Select a certain desired trait • Breed two animals displaying that trait • The result is offspring displaying the trait

  7. Natural Selection • Darwin proposed the same thing was happening naturally in the animal and plant world • He based his ideas on 4 principles: • Overproduction: When a species produces more offspring than can live in the environment • Variation: mutations that naturally occur in the genetic material • Adaptation: any inherited trait that gives an organisms an advantage to survive • Selection: if a trait helps an organism survive to reproduce, the trait has been “selected”

  8. Speciation • The evolution of new species from an existing organism • Can occur when the environment changes dramatically such as a volcanic eruption • New species can also occur when the environment changes gradually

  9. Formation of New Species due to Isolation Example from a population of Cichlids (fish) • Water level is low, one species lives in a lake • Level rises filling shoreline, population spreads throughout the lake • Level falls, isolating the fish from each other • New species development that are more successful in their environment

  10. Isolation Can Lead to New Species • Scientist believe that Isolation is essential to speciation • Isolation can occur due to geographic changes such as mountains building up • Cases caused by isolation have led to the great level of biodiversity on Earth

  11. CH 7 Classification of Living Things

  12. CH 7 Objectives • Explain why scientists classify living things • Describe evidence scientist use to classify organisms • Explain how scientific names are determined and give examples • Use the 7 levels of classification to identify an organism • Describe organisms found in each of the current 6 kingdom system of classification • Describe the 3 domains • Describe how dichotomous keys can be used to identify organisms • Utilize a dichotomous key to identify common household objects

  13. Essential Questions and Understanding • Understand how scientist study biological relationships to classify living organisms • How has our classification system changed over time? • Describe how we give organisms scientific names and give and example. • Use a dichotomous key to classify organisms correctly • Identify characteristics of organisms found in the 6 kingdoms

  14. 1600’s: organisms were classified based on appearance and behavior • PROBLEM: Can be deceiving, not universal (i.e. they could not ALL agree on a system for naming organisms) • 1700’s: 2 Kingdoms (Plant and Animal) • Linnaeus set a standard 2 name system for each animal (Genus species) • Linnaeus developed a system for naming species and organizing them into groups 1866: 3 Kingdom Sytem (plant, animal, protista) • 20th Century: Started using DNA and genes to classify related species • 1925: 2 Kingdoms (Prokaryota & Eukaryota) • 1938: 4 Kingdoms (Monera, Protoctista, Plantae, Animalia) • 1969: 5 Kingdom System (Monera, Protista, Plantae, Fungi, Animalia) • 1977: Current 6 Kingdom System • 2000’s:???? 7 Kingdoms???? No Kingdoms??? Domains??

  15. Classification • Classification is the process of arranging organisms into groups based on similarities • Taxonomy: science of naming and classifying organisms • To classify organisms scientists use similarities and differences among species • A classification system (such as one found in a field guide can help you identify unfamiliar organisms • A taxon is a group of organisms that share certain traits based on shared ancestors. • Not All organisms that look alike are closely related

  16. Binomial Nomenclature • Each organism has a 2 part name • Scientific name • Written in Latin and Greek • Genus species • Genus: a group of species with similar characteristics • Species: the specific name for the organism (contains the least number of organisms) • EX) Homo sapiens (human), Aubrietagracilis (flower), Chameleogracilis (chameleon), Mammillariagracilis (cactus)

  17. 7 Levels of Classification to Name a Species • Each level is more specific than the last • Kings Play Chess On Fat Green Stools • Kingdom • Phylum • Class • Order • Family • Genus • Species

  18. Dichotomous Keys • Asks a series of questions that can be answered in only two ways. • Each answer leads to another question until you identify the organism

  19. KEY TO THE CRITTERS ON BEBONK 1. Has 1 hair………………………………………………..2 Has 2 hairs………………………………………………4 2. Has a belly button…………………………………BIP Has no belly button………………………………3 3. Has 2 legs………………………………………………GLIP Has 4 legs……………………………………………FOOP 4. Has arms…………………………………………….GLOP Has no arms……………………………………….NOP

  20. Kingdom Plantae • Multicellular • Live on water and land • Obtain energy from sunlight • Have a nucleus, cell wall, chloroplast • EX) grass, trees, moss

  21. Kingdom Animalia • Multicellular • Live on water and land • Obtain energy by eating food • Have a nucleus, no cell wall, no chloroplast • Have the ability to move • EX) human, elephant dog, fish bugs

  22. Kingdom Protista • Most are unicellular • Nucleus • Have the ability to move • Some eat like animals • Some get energy from sunlight • EX) Sea weed, Kelp, Euglena

  23. Kingdom Fungi • Takes nutrients from environment • Rooted in one place • Have cell walls • Act as decomposers • EX) Mushroom, yeast, molds

  24. Kingdom Archaea • No Nuclei • Live in extreme environments-high heat, high salt, high sulfer • EX) Methanococcoidesburtonii

  25. Kingdom Bacteria • Unicellular • No Nuclei • Reproduce by dividing in two • Can move • EX) E. Coli