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Transcript
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 – Describes the theory that life has evolved from simple to more complex forms and that evolution is an ongoing process. Fact –OR- Fiction • Lizards are more closely related to birds than crocodiles. • FACT. Genetically more similar to a bird! 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 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. Fact –OR- Fiction • Dragonflies were once as large as pigeons. • FACT. Fossils reveal that giant dragonflies inhabited earth 290 million years ago. Fossils, Etc. Ms. Johnson Ms. Doncaster Biology – Level 4 SC.NL.04.01 • Describes how the biochemical and physical nature of the earth determines how life evolves. 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 Numbers • Current # of species: 5-30million (only a fraction of what once was…) • 99% of all organisms ever, now extinct • Life – 4 billion years Where did all the mammals go? • Evolved 200mil yrs ago • Who studies fossils? – Paleontologist • How are fossils studied? – Anatomical, Molecular, Biogeographical 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 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) Transitional Fossils • Hard to find • Most DON’T lead to common ancestor, but to “close cousins” 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 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!! Vocab • Phylogeny – History of an organism’s development • What current mammal is most closely related to the whale? • Yeah!!! Hippopotamus!!! Fossil Dating • Relative Dating • Radiometric Dating Relative Dating • Older deposits found beneath more recent • Geologic layers (with no/little geologic activity) • Two fossils. Same layer, ∴ Same time period 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 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 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 Radiometric Dating – Half-Life • 40K decays to Ar • 40K half-life is 1.3bil years!! Radiometric Dating • Oldest fossil: ancient prokaryote • Purpose: construct an evolutionary timeline Eras, Periods, Epochs • Remember…Life – 4 billion years • Divided into Eras periods epochs • Defined by fossil finds!! 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) Standard 1 Is hIstory… SC.NL.04.02 Uses the Darwinian theory to explain how organisms must adapt to survive. SC.NL.04.02 – Species Species are unique Species: interbreeding populations 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) 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” SC.NL.04.02 – Adaptation Sometimes traits can be harmful Inherited traits will determine SURVIVAL Sometimes traits can be beneficial ADAPTATION (increases survival rate) SC.NL.04.02 – Adaptation Ex: Termites, Anteaters Small area, large population (termites) Competition: two populations trying to occupy the same niche 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? 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” SC.NL.04.02 – Mr. Darwin & Co. 1809 Jean-Baptiste Lamarck Challenged Bonnet Fossils were ancestors of modern life 1. Organisms strive for improvement 2. Principle of Use/Disuse 3. Only useful parts passed on (Sorry Lamarck, your principle later disproved by mice) Notes: Lamarck, Principle of Use DISproved! 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 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 SC.NL.04.02 – Natural Selection 1. Variation w/in populations 2. Traits passed, but no info on genetics yet Some variations are favorable Improves organism’s function and reproduction Ex) Fast ostriches outrun predators SC.NL.04.02 – Natural Selection 3. Not all young produced in each generation can survive 4. Disease, starvation, predators Individuals that survive and reproduce are those with favorable variations 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. SC.NL.04.02 Conflicting Theories Help to Drive Research about Evolution 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… 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- 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 SC.NL.04.03 – Types of Evolution • 3 Types of Evolution – Divergent – Convergent – Coevolution 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. 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 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 SC.NL.04.03 – Convergent Evolution • Paper clip experiment • Think of a random use of a paperclip (must be different from neighbor’s) and submit. SC.NL.04.03 – PaperClip Ideas • • • • • • • • • • • • Hold an ornament Stress reliever Nail cleaner Body piercing Prison shank Contact Lens Remover Nose plugger Pick a lock Electrical conductor Spring Paper flicker Spear Insects • • • • • • • • • • • Clean ears Zipper replacement Shootable object Piercing Needle Blow Gun Dart Ring / Jewelry Key Chain Braces Zipper replacement Explosive Opening windows SC.NL.04.03 – PaperClip Ideas • • • • • • • • Guitar Pick Shoelace Clip Button Nail Polish Remover Earring Sewing Needle Pick to Unlock Doors Earring • • • • • • • Fake Nails Nail Cleaner Fish Hook Key Earring Chew Toy RAWR!!!1 Ring / Jewelry SC.NL.04.03 – Convergent Evolution • Compare with others’ • Note that some people came up with same ideas. • Darwin had the same illustration for convergent evolution. Darwin reviewed 2 people coming up with same invention • Natural selection will produce similar adaptations even though groups of organisms are separate. SC.NL.04.03 – CoEvolution • Animals adapt not just to the environment, but also with other plants and animals • Coevolution: species that interact and adapt to one another • Even plants! – Flower color/scent attracts certain animals – Hummingbirds! SC.NL.04.03 – Adaptive Radiation • Populations will fill empty habitats (& niches) • Adaptive Radiation: many diverse species from common ancestor • Back to Darwin’s finches! SC.NL.04.03 – Darwin’s Finches • Different finches lived on different islands (Galapagos Is.) • All started on one island, then migrated • Features link them to original ancestor, but not to each other SC.NL.04.03 – Prokaryote Dev’t • So, Did cells evolve the same way? • Most scientists say the first cells were heterotrophs – They competed for organic compounds and emitted CO2, and the strongest survived • Variations occurred, autotrophs resulted – Autotrophs didn’t compete for organics SC.NL.04.03 – Prokaryote Dev’t • Autotrophs not yet photosynthetic (plants came later) • Were probably anaerobes – Bacteria, etc. – Developed ability to tolerate oxygen and surfaced SC.NL.04.03 – Eukaryote Dev’t • 3.5 bil yrs ago, heterotrophs (pro-k) • 2.5 bil yrs ago, autotrophs (pro-k) • 1.5 bil yrs ago, Eukaryotes!! • How did eukaryotes develop inner membranes? – Infolding – Endosymbiosis SC.NL.04.03 – Eukaryote Dev’t -Infolding• Cell membrane folded in • Created compartments – ER, Golgi, Vacuole SC.NL.04.03 – Eukaryote Dev’t -Endosymbiosis• Mitochondrion, Chloroplast types of prokaryotes that were engulfed • Remember…DNA? • And then… eukaryotic cells led to multicellular organisms SC.NL.04.03 – Back to Genetics • Individuals exhibit unique characteristics, but evolution can only be measured in terms of populationSSSS • Gene pool: ALL genetic material in a given population • ALL genes for EVERY trait on EVERY chromosome of a species SC.NL.04.03 – Equilibrium • Hardy-Weinberg principle– Under specific conditions, allele frequencies remain constant (though don’t have to be the same) – (Feed roses same food, same amts of water every year, will always be 50% white, 30% pink, 20% yellow) • However, there can be no favoritism or competition for equilibrium to happen SC.NL.04.03 – Distributions • Normal Number of Organisms Normal Distribution Curve SC.NL.04.03 – Distributions • Directional Directional Selection Curve Number of Organisms Normal Directional • No snow for a while, white rabbits now prey and dark rabbits camouflaged SC.NL.04.03 – Distributions • Disruptive Normal Disruptive Selection Curve Number of Organisms Disruptive • Dark ground, light green/white shrubs, grey rabbits not protected SC.NL.04.03 – Simple to Complex • Artificial Selection – Farmers choose most desirable traits to breed • • • Cows give more milk Horses hardier Wild mustard plant yields: – Broccoli, cauliflower, brussel sprouts, cabbage – Darwin suspects this also happens in nature SC.NL.04.03 – Simple to Complex • Geology – Geologic change is slow and uniform. Gradual change will influence plants/animals SC.NL.04.03 – Simple to Complex • Population Control – When population is too large and supplies are all used; war, starvation, and disease will result – So, not all offspring will survive – Compete for food, water, space And the STRONG will SURVIVE