Upload
percival-cole
View
218
Download
3
Tags:
Embed Size (px)
Citation preview
Evolution
Fossils
• Found in sedimentary rock• Organism preserved in rock before
decay• Types:
• Imprint• Mold• Cast• Petrified
Imprint Fossil
Mold Fossil
Cast Fossil
Petrified Fossil
Dating• Relative Dating: determining age in
relation to other fossils
• Absolute Dating: using radioactive particles to find an estimated age of rock/organism
• Radioactive Isotope: atom with unstable number of neutrons; unstable atoms change into more stable atoms over time
Relative Dating
Absolute Dating
History of EvolutionEvolution: How things change over time
1. Jean Baptiste de Lamarko Inheritance of acquired characteristicso Use and disuse (Ex. Giraffes)
2. Alfred Russel Wallaceo Same arguments/conclusions as Darwino Not credited with the theory of evolution
3. Charles Darwino Conclusion natural selection as a
mechanism for change
Artificial Selection
• Artificial Selection: human intervention in animal/plant reproduction (genetic engineering)
• Ex. Fruit/vegetable size, milk-producing cows, dog breeders
Darwin’s Theory of Evolutionby Natural Selection
1. Variations exist within populations • Finches and beak sizes, human height
2. Some variations are more advantageous for survival/reproduction• Peppered moths
http://www.biologycorner.com/worksheets/pepperedmoth.html
Darwin’s Theory of Evolutionby Natural Selection
3. Organisms produce more offspring than survive• Fish, frogs
4. Overtime, offspring of survivors make up a larger portion of populations• Those that die take poor traits with
them• SURVIVAL OF THE FITTEST!!
Natural Selection
• Acts on the phenotype of an organism
• With a change in environment a trait may become advantageous and organisms that have that trait are more likely to survive
Adaptations
• Variation in a population that provides an advantage in a specific environment
Types of Adaptations
1. Structural• Change in structure• Ex. Wings, lungs
2. Physiological• Internal adjustment (chemical change)• Ex. Adrenalin
3. Behavioral• Action • Ex. Survival instinct
Evidence of Evolution
1. Homologous Structures• Similar structure• Ex. Limb of salamander, lizard, turtle
2. Vestigial Structures• Body parts with no function• Ex. Human appendix, ear wiggling
muscles, wisdom teeth, hip bone in whale
Evidence of Evolution
1. Homologous Structures• Similar structure• Ex. Limb of salamander, lizard, turtle
2. Vestigial Structures• Body parts with no function• Ex. Human appendix
Evidence of Evolution
3. Analogous Structures• Similar function, different structure• Ex. Insect and bird wing
4. Embryonic Development• Gill slits and tails• DNA/amino acid comparison
Human beta chain 0
Gorilla 1
Gibbon 2
Rhesus monkey 8
Dog 15
Horse, cow 25
Mouse 27
Gray kangaroo 38
Chicken 45
Frog 67
Lamprey 125
Sea slug (a mollusk) 127Soybean
(leghemoglobin)124
Number of amino acids that are different than the human hemoglobin beta chain
Gill slits
tail
How Does Evolution Work?Two Theories:
1. Gradualism• Gradual change of species over time • Fossil record supports this theory
2. Punctuated Equilibrium• Step-like pattern in a series over a
period of time• Ex. Volcano eruption, meteor (change in
form was immediate)• Parts of fossil record support this
Natural Selection
• Acts on the phenotype of an organism
• Harmful, recessive allele takes long time to disappear
• With a change in environment a trait may become advantageous
Terms• Gene pool:
– all genes in a population• Allele:
– Alternate form of a gene (one of a pair)
– ex. brown and blue eye color• Allele frequency:
– percentage of a particular allele in the gene pool
Terms
• Species: – group of organisms that interbreed
and produce fertile offspring
Terms
• Genetic equilibrium: – allele frequency in a population
remains the same means that evolution is not occurring
• If allele frequency changes, genetic equilibrium altered and evolution is occurring
How does gene pool change?
1. Mutation2. Genetic drift3. Gene flow
Three Types of Natural Selection
1. Stabilizing Selection• Favors intermediate• ex. 20th century babies 8 lbs. survive
2. Directional Selection• Single extreme is selected for• ex. long-necked giraffes
3. Disruptive Selection• Extremes are selected for, intermediate
selected against• 2 separate populations have distinct
characteristics
Natural selection may result in a new species (speciation) if a permanent barrier prevents breeding between members of a species
Two Types of Genetic Isolation
1. Geographic Isolation• Physical barrier separates a population
into different groups
2. Reproductive Isolation• Species in the same area, cannot share
DNA due to differences in reproductiona) Seasonal b) Behavioral c) Mechanical d) Gametic
Trends in Evolution1. Divergent Evolution
• Related species become less alike because separated by barrier
2. Convergent Evolution• Unrelated species become similar
3. Parallel Evolution• 2 different species in two different
environments develop same type of adaptation due to similar selective pressure
Evidence for Evolution and Classification
1. Homologous Structures2. Analogous Structures3. Vestigial Structures4. DNA Relationships5. Embryonic Development6. Fossils7. Radioactive Dating
Taxonomy
• Science of classifying organisms• Carolous Linnaeus = father of binomial
nomenclature• Binomial Nomenclature = latin, 2 names• Ex. Homo sapiens (Genus species)
• Ursus horribulus (grizzly bear)• Ursus americanus (American black bear)• Turdus migratorius (Robin)
Naming System (General Specific)
• Kingdom…..Animalia• Phylum……Chordata• Class………Mammalia• Order………Primates• Family…….Hominidaea• Genus……..Homo• Species……Sapiens
Kingdom Phylum Class Order Family Genus Species
• Kings Play Chess On Fine Glass Sets
• Kings Play Chess On Fuzzy Green Sofas
• King Philip Came Over From Germany Singing
• King Philip Crossed Over For Green Spaghetti
Kingdoms (5)
5 Characteristics Used to Classify Kingdoms
1. Complexity…• Prokaryotic vs. eukaryotic
2. Organization…• Unicellular vs. multicellular
3. Feeding…• Autotrophic vs. heterotrophic
4. Movement…• Sessile vs. motile
5. Reproduction…• Asexual vs. sexual
Classification
• Phylogenetic Tree: – shows evolutionary relationships– graphical representation of
relationships between organisms
• Dichotomous Key: – checkpoint used to classify organisms– Always have two choices