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Evolution, Biodiversity, and Community Processes

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  1. Evolution, Biodiversity, and Community Processes La Cañada High School Dr. E

  2. What types of Life exist on the Earth?

  3. Types of Organisms • Prokaryotic Kingdom: single-celled organisms containing no internal structures surrounded by membranes (therefore there is no nucleus) • Monera – bacteria and cyanobacteria

  4. Endosymbiotic Theory Chloroplast Plants and plantlike protists Aerobic bacteria Ancient Prokaryotes Photosynthetic bacteria Nuclear envelope evolving Mitochondrion Primitive Photosynthetic Eukaryote Animals, fungi, and non-plantlike protists Ancient Anaerobic Prokaryote Primitive Aerobic Eukaryote

  5. Types of Organisms • Eukaryotic Kingdoms: all organisms consisting of cells which contain membrane-bound nuclei • Protista - mostlyone-celled organisms – have characteristics of all three other Eukaryote Kingdoms • Fungi - organisms which decompose stuff • Plantae - organisms which use photosynthesis to make their own food • Annuals completelife cycle in one season • Perennialslive for more than one season • Animalia - organisms which must get organic compounds from food they eat - most are able to move • Invertebrates – no backbone • Vertebrates – Fish, Amphibians, Reptiles, Birds and Mammals

  6. Naming Species

  7. Naming of Species The system of naming species was first developed by Swedish botanist and physician, Carolus Linnaeus in the mid- 1700s • Taxonomy, which seeks to describe, name and classify organisms • begins with assigning all species a two-part Latin name called a binomial • first word of the binomial is the genus name of the species, • second word is the specific epithet for the species.  • scientific name for the blue crab  is Callinectes sapidus • Callinectes, the genus name, is the collective term which includes many species of crabs closely related to the blue crab • sapidus, describes exactly which of the Callinectes species is being identified

  8. Definition of Species • Morphological Species Concept (MSC) • traced back to the philosophies of Plato and Aristotle, and which continued to be used until the first half of the twentieth century • defines species purely by their phenotypic traits rather than their genetic complement or potential interbreeding • number of species classified was large because each group of individuals that exhibited a slight phenotypic difference were considered a different species http://www.falcons.co.uk/mefrg/Falco/13/Species.htm

  9. Definition of Species • Biological Species Concept (BSC) • ‘a species is a group of interbreeding populations that are genetically isolated from other groups by reproductive isolating mechanisms such as hybrid sterility or mate acceptability’ • Phylogenetic Species Concept (PSC • Each population of sexually reproducing organisms that possesses at least one diagnostic character present in all population members but absent from all closest relatives is considered a species • each geographically distinct form is classified as a species http://www.falcons.co.uk/mefrg/Falco/13/Species.htm

  10. How did Life Originate?OrChemical Evolution

  11. EVOLUTIONisGradual Change

  12. Origin of Life • 600 BC Anaximander • life began in water. • early forms were simple. • simple forms begat more complex forms over time • Aristotle (350 BC) • decaying material could be transformed by the ‘Spontaneous Action of Nature' into living animals • ArchBishop Usher (early 1600’s) and his scholars • provided exact dates for all the various occurrences in the new Bible being translated for King James • ‘proved’ to the King that the world was created on Tuesday, October 8, 4004 BC at 9:30 in the morning

  13. Chemical Evolution Oparin Hypothesis (early 1930s) 1) Formation of the planet with gases in the atmosphere that could serve as the raw materials for life. • most widely accepted astronomical theory for the origin of the earth and the rest of the solar system is that the solar system formed about 4.7 billion years ago from a diffuse dust cloud • central portion probably condensed to form the sun and areas in the outer parts of the cloud condensed to form the planets • beginning of the universe according to the "Big Bang" theory occurred about 15 billion years ago

  14. Chemical Evolution Oparin Hypothesis 2) Random synthesis of simple organic molecules (such as amino acids that make up proteins) from the gases in the surrounding atmosphere. 3) Formation of larger, more complex molecules (Macromolecules) from the simple organic molecules, e.g., the formation of simple proteins. 4) Formation of coacervates - unique droplets containing the macromolecules , i.e., a coacervates consists of chemicals suspended within a liquid surrounded by a membrane, e.g. a droplet consisting of chemicals in water surrounded by an oil layer membrane.

  15. Chemical Evolution Oparin Hypothesis 5) Development of some type of chemical organizers that function to give these droplets the ability to take in molecules, discharge other molecules, and control and maintain a characteristic chemical pattern. These chemical organizers would probably be similar to nucleic acids (that make up chromosomes). 6) Development of controlled reproduction to insure that resultant daughter cells have the same chemical capabilities. The droplets could now be considered to be primitive cells. 7) Beginnings of evolutionary developments so that a group of cells could adapt to changes in the environment over time.

  16. Miller-Urey Experiment • conducted in 1953 by Stanley Miller with Harold Urey • the first experiment to about the evolution of prebiotic chemicals and the origin of life on Earth • mixture of methane, ammonia, hydrogen, and water vapor introduced into a 5-liter flask (simulate the Earth's primitive, reducing atmosphere) • energized by an electrical discharge apparatus to represent ultraviolet radiation from the Sun • products were allowed to condense and collect in a lower flask which modeled a body of water on the Earth's surface

  17. Miller-Urey Experiment • heat supplied to this flask recycled the water vapor just as water evaporates from lakes and seas, before moving into the atmosphere and condensing again as rain • after a day of continuous operation • a thin layer of hydrocarbons on the surface of the water • after about a week of operation • a dark brown scum had collected in the lower flask and was found to contain several types of amino acids, including glycine and alanine, together with sugars, tars, and various other unidentified organic chemicals

  18. The Just-Right Planet Read Core Case Study on page 82!

  19. Evolution of First Life • Formation of the earliest precursors of life • must have self-organized • acquired the capabilities needed to survive and reproduce • Biomolecules of life became enclosed within a lipid membrane • forming rudimentary assemblages that resembled cells or protocells • Essential protocellular functions • acquisition of energy from the environment • use of energy to synthesize molecules – metabolism • information transfer to succeeding generations – genetics

  20. Evidence

  21. Fossils • Oldest fossils are the approximately 3.465 billion-year-old microfossils from the Apex Chert, Australia • colonies of cyanobacteria (formerly called blue-green algae) which built real reefs

  22. Fossils 1600's - Danish scientist Nicholas Steno studied the relative positions of sedimentary rocks • Layering is the most obvious feature of sedimentary rocks • formed particle by particle and bed by bed, and the layers are piled one on top of the other • any sequence of layered rocks, a given bed must be older than any bed on top of it • Law of Superposition is fundamental to the interpretation of Earth history, because at any one location it indicates the relative ages of rock layers and the fossils in them.

  23. Half-life for a given radioisotope is the time for half the radioactive nuclei in any sample to undergo radioactive decay

  24. Half-life for a given radioisotope is the time for half the radioactive nuclei in any sample to undergo radioactive decay

  25. Biological Evolution

  26. (ORGANIC) EVOLUTION: change in gene frequencies within populations from generation to generation.

  27. (ORGANIC) EVOLUTION: gene frequencies over time…no concepts of “planning” or “progress” apply. No goals!

  28. Early Evolutionists’ Anthropocentric view: Scala Natura (ladder of life). A linear rise from ‘primitive’ to ‘advanced’.

  29. Early Evolutionists’ Anthropocentric view: Scala Natura (ladder of life). Needless to say, we are the most ‘advanced’ in this scheme…after all, it’s our ladder!!

  30. Evolutionary Bush One life-form splits into two and those branches split (independently) to make more. Time   Phenotypic ‘distance’

  31. Evolutionary Bush -- thousands of earlier and later branches.

  32. At any given moment (e.g. the ‘present’), all we see is current diversity…all extinct forms are gone (99.9%) Time 

  33. Four causes of evolutionary change: • Mutation: fundamental origin of all genetic (DNA) change.

  34. Four causes of evolutionary change: • Mutation: fundamental origin of all genetic (DNA) change. Point mutation …some at base-pair level

  35. Four causes of evolutionary change: • Mutation: fundamental origin of all genetic (DNA) change. Crossing-over …others at grosser chromosome level

  36. Four causes of evolutionary change: • Mutation: fundamental genetic shifts. • Genetic Drift: isolated populations accumulate different mutations over time. In a continuous population, genetic novelty can spread locally.

  37. Four causes of evolutionary change: • Mutation: fundamental genetic shifts. • Genetic Drift: isolated populations accumulate different mutations over time. Local spreading of alleles

  38. Four causes of evolutionary change: • Mutation: fundamental genetic shifts. • Genetic Drift: isolated populations accumulate different mutations over time. Local spreading of alleles

  39. Four causes of evolutionary change: • Mutation: fundamental genetic shifts. • Genetic Drift: isolated populations accumulate different mutations over time. Spreading process known as ‘gene flow’.

  40. Four causes of evolutionary change: But in discontinuous populations, gene flow is blocked.

  41. Four causes of evolutionary change: Variations accumulate without inter-demic exchange