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The Evolving Nature of Life

The Evolving Nature of Life. Ms. Johnson Ms. Doncaster Biology – Level 4. Standards. SC.NL.04.01 Describes how the biochemical and physical nature of the earth determines how life evolves. SC.NL.04.02 Uses the Darwinian theory to explain how organisms must adapt to survive. SC.NL.04.03

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The Evolving Nature of Life

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  1. The Evolving Nature of Life Ms. Johnson Ms. Doncaster Biology – Level 4

  2. Standards • SC.NL.04.01 • Describes how the biochemical and physical nature of the earth determines how life evolves. • SC.NL.04.02 • Uses the Darwinian theory to explain how organisms must adapt to survive. • SC.NL.04.03 • Describes the theory that life has evolved from simple to more complex forms and that evolution is an ongoing process.

  3. Fact –OR- Fiction • Lizards are more closely related to birds than crocodiles. • FACT. Genetically more similar to a bird!

  4. Fact –OR- Fiction • In a healthy population, everyone has the same genes. • FICTION. Variety can be a result of mutations, which can be key to a population’s survival

  5. Fact –OR- Fiction • Panda bears are NOT bears. • FACT & FICTION. Most scientists classify the giant panda as a bear, but the red panda actually a type of raccoon.

  6. Fact –OR- Fiction • Dragonflies were once as large as pigeons. • FACT. Fossils reveal that giant dragonflies inhabited earth 290 million years ago.

  7. Fossils, Etc. Ms. Johnson Ms. Doncaster Biology – Level 4

  8. SC.NL.04.01 • Describes how the biochemical and physical nature of the earth determines how life evolves.

  9. Hmmm… • Biodiversity - variety and abundance of diff’t species in a community. • Change can create advantages/disadvantages • Nat’l Disaster: Those who adapt better (more traits), more likely to survive

  10. Numbers • Current # of species: 5-30million (only a fraction of what once was…) • 99% of all organisms ever, now extinct • Life – 4 billion years

  11. Where did all the mammals go? • Evolved 200mil yrs ago • Who studies fossils? • Paleontologist • How are fossils studied? • Anatomical, Molecular, Biogeographical

  12. Fossil Vocab • Fossil record – information stored in fossils • T/F Are all fossils bones? • Fossils found in sedimentary rock (sand/silt settled at bottom of body of water) • Compressed • Water becomes dry land • Fossils hard to find, vulnerable to weather and erosion

  13. Basilosaurus • In the middle of the Sahara, hundreds of whale skeletons • Keep digging…Basilosaurus had legs!! • Now in search of transitional fossils (fossils between related fossils)

  14. Transitional Fossils • Hard to find • Most DON’T lead to common ancestor, but to “close cousins”

  15. Vocab • Homologous structures • Different species, same characteristics • Ex: Front fin of a whale (humerus, radius, ulna) • Also found in other mammals: humans, wolves, sea lions • Sequencing • DNA base or amino acid • Molecular biologist compare proteins

  16. Vocab • Vestigial structures • Inherited, but size reduced and often unused • Ex) Pythons (hip/leg bones) • Ex) Humans (appendix) • Analogous structures • Same function, different structures • Ex) Bat, Bird, Insect • WINGS!!

  17. Vocab • Phylogeny – History of an organism’s development • What current mammal is most closely related to the whale? • Yeah!!! Hippopotamus!!!

  18. Fossil Dating • Relative Dating • Radiometric Dating

  19. Relative Dating • Older deposits found beneath more recent • Geologic layers (with no/little geologic activity) • Two fossils. Same layer, ∴ Same time period

  20. Relative Dating • Rock layers do not determine age, but serves to put layers in order of age • Real age estimated by analyzing isotopes of surrounding rocks

  21. Radiometric Dating • Isotope: Single atoms of same element with different # of neutrons • Weight changed • Charge unchanged • Some isotopes “radioactive” • During decay, isotopes give off particles and energy

  22. Radiometric Dating • Radioactive isotopes break down (decay) matter at a constant rate • Rates of decay: half-lives • Half-live: the time it takes for ½ of the original isotope to decay into a different isotope • *Note* Every isotope has a different, but known rate

  23. Radiometric Dating – Half-Life • 40K decays to Ar • 40K half-life is 1.3bil years!!

  24. Radiometric Dating • Oldest fossil: ancient prokaryote • Purpose: construct an evolutionary timeline

  25. Eras, Periods, Epochs • Remember…Life – 4 billion years • Divided into Eras  periods  epochs • Defined by fossil finds!!

  26. Eras, Periods, Epochs • Precambrian Era (590mil yrs ago) • Paleozoic Era (248-590mil yrs ago) • 6 periods… • Mesozoic Era (65-248mil yrs ago) • Triassic Period • Jurassic Period • Cretaceous Period • Cenozoic Era (0.01-65mil yrs ago)

  27. Standard 1 Is history…

  28. SC.NL.04.02 Uses the Darwinian theory to explain how organisms must adapt to survive.

  29. SC.NL.04.02 – Species • Species are unique • Species: interbreeding populations

  30. SC.NL.04.02 – Variation • Within a species’ is a good amount of variation • Variation: differences between individuals in a population • Subtle/Dramatic - (color, communication, shape of teeth, number of offspring, territory size, diet)

  31. SC.NL.04.02 – Variation • Most variations are genetic • Mutation • Change in gene sequence • Ex: Red fox becomes silver • Recombination • Allele from “Mom” mixes with allele from “Dad”

  32. SC.NL.04.02 – Adaptation • Sometimes traits can be harmful • Inherited traits will determine SURVIVAL • Sometimes traits can be beneficial • ADAPTATION (increases survival rate)

  33. SC.NL.04.02 – Adaptation • Ex: Termites, Anteaters • Small area, large population (termites) • Competition: two populations trying to occupy the same niche

  34. SC.NL.04.02 – Adaptation • Become suited to a certain niche • Niche: Role a population plays in an environment • Live? Eat? Raise Offspring? Predators? Temp?

  35. SC.NL.04.02 – Mr. Darwin & Co. • 1769 Charles Bonnet • Fossils didn’t look like modern lifeforms • Catastrophes must have affected earth, and life began again • Coined the term “evolution” (change over time) Notes: • Bonnet, earth catastrophes, “evolution”

  36. SC.NL.04.02 – Mr. Darwin & Co. • 1809 Jean-Baptiste Lamarck • Challenged Bonnet • Fossils were ancestors of modern life • Organisms strive for improvement • Principle of Use/Disuse • Only useful parts passed on (Sorry Lamarck, your principle later disproved by mice) Notes: Lamarck, Principle of Use DISproved!

  37. SC.NL.04.02 – Mr. Darwin • 1831 Darwin travels on HMS Beagle • Studies plants/animals around the world • Esp. Finches (diff groups had own niche) • Later, YES, really were 13 species

  38. SC.NL.04.02 – Mr. Darwin • 1844 Thee Paper of All Papers! • 1858 Finally published (scared to publish) • On the Origin of Species by Means of Natural Selection

  39. SC.NL.04.02 – Natural Selection • Variation w/in populations • Traits passed, but no info on genetics yet • Some variations are favorable • Improves organism’s function and reproduction • Ex) Fast ostriches outrun predators

  40. SC.NL.04.02 – Natural Selection • Not all young produced in each generation can survive • Disease, starvation, predators • Individuals that survive and reproduce are those with favorable variations

  41. SC.NL.04.02 – Natural Selection • Natural selection ultimately results in evolution • Gradualism: small genetic changes occurring over time • (But shouldn’t we see this in fossils?) • Punctuated Equilibrium: quick change b/c of environment, etc.

  42. SC.NL.04.02 Conflicting Theories Help to Drive Research about Evolution

  43. SC.NL.04.03 – Simple to Complex • Krakatoa- • Volcano – 1883 • Destroyed island, left only ash • No other land for 40km • Now has new plants/animals…

  44. SC.NL.04.03 – Speciation • Evolution – process by which populations change in response to their environment • Sometimes organisms change so much that they can’t interbreed with the ancestor species, this means it IS a new species!!! -SPECIATION-

  45. SC.NL.04.03 – Speciation • New species come when separated from original population (i.e. by geography) • They adapt (and biologically change) to the new environment

  46. SC.NL.04.03 – Types of Evolution • 3 Types of Evolution • Divergent • Convergent • Coevolution

  47. SC.NL.04.03 – Divergent Evolution • Same species evolve independently • Ex. by geography • or small group leaves the herd • Ex. Brown bears migrated to ice, adapted to become polar bears • Remember…According to natural selection, the animals with the advantageous traits survived and passed them on to offspring.

  48. SC.NL.04.03 – Convergent Evolution • Unrelated species display similar features • Can mislead scientists to think animals are more similar than genetically are • Cross-check with embryology, biochemistry

  49. SC.NL.04.03 – Convergent Evolution • Serval Cat vs. Maned Wolf • Both have: • Long ears to hear prey • Eat rodents, lizards • Long legs for chasing

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