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1 what themes explain how present day organisms developed from earlier life forms 2 what is the time frame for evolutionary change two major trends over time 1 simple to 2 water dwelling organisms evolution process of change over time complex to land amphibians move out of water but still need to return to reproduce first life 3.5 billion years ago prokaryotes similar to modern day bacteria reptiles become dominant time frame for evolution gradualism rodhocetus ambulocetus spent little time on land reduced hind limbs able to swim with an up and down motion like modern whales mesonychid walked on land but spent time in the water swimming like an otter punctuated equilibrium

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phylogenetic tree of life ·top of the tree species that currently exist ·as you to towards the base you are going back in time all life shares the same genetic code dna is too detailed to have been invented twice r dawkins 2004 dna in all creatures has been handed down from remote ancestors we can read this records using biotech methods to spell out dna segments or to look at the protein products of dna

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3 4 what evidence is used to show that evolution has occurred how are the puzzle pieces of evidence put together to produce the entire evolution puzzle 1 fossils or of organisms that no longer exist trace remains although the fossil record will never be complete it contains striking evidence that evolution has occurred scientists can determine the age of fossils fairly accurately by using radiometric dating this enables them to arrange fossils in sequence from oldest to youngest mold impression made in the substrate a negative image of the organism cast formed when a mold is filled in trace evidence of life forms ·tracks ·nests ·eggs ·coprolites feces ·tooth marks petrified rock-like minerals seep in slowly and replace the original organic tissues with silica calcite or pyrite forming a rock-like fossil true form fossils remains of actual organisms ·in ice ·in amber ·la brea tar pits transitional fossils give us clues intermediary forms ·jaws with sharp teeth ·three fingers with claws ·a long bony tail ·hyperextensible second toes killing claw ·feathers which also suggest homeothermy evidence common ancestor for reptiles birds archaeopteryx missing link the features above make archaeopteryx the first clear candidate for a link between dinosaurs and birds thus archaeopteryx plays an important role not only in the study of the origin of birds but in the study of dinosaurs piece together a puzzle of change through time

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the oldest known fossils are cyanobacteria prokaryotes from archaean rocks of western australia at right is a layered stromatolite produced by the activity of ancient cyanobacteria the layers were produced as calcium carbonate precipitated over the growing mat of bacterial filaments the minerals along with grains of sediment precipitating from the water were then trapped within the sticky layer of mucilage that surrounds the bacterial colonies which then continued to grow upwards through the sediment to form a new layer as this process occurerd over and over again the layers of sediment were created this process still occurs today dated 3.5 billion grypania spiralis locality michigan usa possibly the oldest eukaryotes ~2 billion years old fossilized trails found in rocks dating back 565 million years are thought to be the earliest evidence of animal locomotion ever found oxford university scientists report these indicate that some ancient creatures moved in a similar way to modern sea anemones

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science daily details of evolutionary transition from fish to land animals revealed tiktaalik provides clues about a key transition in the history of life now extinct this organism was a close relative of one our own ancestors the first vertebrate to evolve four limbs and crawl out onto dry land the evolutionary tree below shows the relationship between tiktaalik other fish and four-legged vertebrates

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5 how can evidences other than fossils explain common ancestory among modern day organisms 2 comparative biochemistry all known organisms are based on the same fundamental biochemical organization · genetic information coded as nucleic acids or for viruses transcribed into n a m r then translated into proteins dna rna ·the genetic code the translation table between dna and amino acids is the same for almost every organism meaning that a piece of dna in a bacterium codes for the same amino acid as in a human cell ·hemoglobins are found in a wide variety of life forms they are all very similar in structure species a b c d e f gorilla rhesus monkey mouse chicken frog lamprey amino acid differences compared to human hemoglobin 1 8 27 45 67 125 note species with fewer amino acid differences share a more recent common ancestor similarities suggest that the development of all vertebrates evolved as new genetic instructions were added to old is used as energy currency by all life a t p chlorophyll is the same basic molecule in all photosynthetic organisms

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3 comparative anatomy · homologous structures similar in structure origin and but functions have different modification descent with as vertebrates evolved particular sets of bones were put to different uses the similarity in the structures can be seen suggesting that all vertebrates share a common ancestor · vestigial structures structures present in an organisms but are smaller no function have a less prominent function or have 4 comparative embryology ·cave dwelling animals have vestigial eyes ·appendix ·coccyx ·ear muscles in humans although certain adult organisms may be very different a comparison of the early stages of embryonic development may show similarities that suggest common ancestry early similarities ·tails ·gill slits evidence of common descent 3.1g some characteristics give individuals an advantage over others in surviving and reproducing and the advantaged offspring ,in turn are more likely than others to survive and reproduce the proportion of individuals that have advantageous characteristics will increase.

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6 what is the driving force for change in organisms 7 how does the evolution of the modern day horse illustrate this wet with tropical vegetation toes ability to walk on the spongy ground drier climate hooves more suited to harder ground changes observed in horse structure 1 feet/toes hooves 2 increase in size 3 change in jaw/teeth these changes were a response to changes in environment 3.1a the basic idea of biological evolution is that the earth s presentday species developed from earlier distinctly different species

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8 who was charles darwin an english naturalist in 1859 he published a book on the origin of species which revolutionized the way people thought about the world he suggested that present day species of plants and animals resulted from a process that he called natural selection in other words today s species evolved from previous species 9 how did he come up with his theory he was hired to travel on the hms beagle on an expedition to chart the coastline of south america his job was to observe and record the wildlife the galapagos islands are a small group of volcanic islands in the pacific ocean off the coast of ecuador he observed that the islands had abundant wildlife these species lived no where else but they resembled the species living on the s american main land how did so many different plants and animals arrived on the islands water currents have allowed many different species to immigrate to the islands some such as sea lions fur seals and penguins could swim with the help of the currents and giant tortoises are known to float and could have been carried by the same currents most reptiles mammals rice rats and insects hitched a ride on rafts of vegetation that broke off during the rainy season spores and seeds could have arrived by wind spiders small insects and tiny land snails are frequently transported by wind as well land birds and bats weak fliers would have to have been blown to the islands seabirds would easily have flown there the birds would often aid plants by ingesting seeds before takeoff and then expelling them at their destination other seeds with tiny hooks could have attached to feathers and feet and been given a free ride still other seeds caked in mud and clinging to a bird s feet or feathers would have been transported there as well once on the islands the various species established themselves and determined territories marine iguanas giant tortoises only known lizards that can swim weigh about 225 kg they have webbed feet and a no competitors or flattened tail predators on the island darwin s finches 13 closely related finches how did these species come to be what happened the birds are all about the same size 10­20 cm the most important differences between species are in the size and shape of their beaks and the beaks are highly adapted to different food sources the birds are all brownish or black their behavior differs and they have different song melodies descent with modification these species resulted from changes to original species probably from s america

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10 what are the mechanisms for natural selection new species arose from ancestors by the gradual accumulation of from his observations darwin made important conclusions overproduction 1 all organisms produce offspring than could survive more predators disease competition cause large numbers of individuals to die in addition many of those that do survive will not live to reproduce · variation 2 organisms in the same species show wide differences unique each organism is advantages disadvantages each has different and some variations are and passed on to the next generation inherited competition 3 since there are more organisms produced than can survive members of each species must compete for limited resources food water shelter mate and if you survive to reproductive age you need to compete for a adaptation inherited trait that improve the chance of survival

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4 natural selection suited live individuals that are better for the environment the ones who survive this is the famous statement survival of the fittest reproduce the ones who survive organisms that are the strongest and fittest pass on their genes to the next generation natural selection occurs when organisms with favorable variations survive reproduce and pass on their variations to the next generation speciation 5 over time favorable traits acummulate changes can lead to the formation of new species organisms with best adaptations survive and reproduce 3.1 e environment is the selecting agent traits that maximize fitness accumulate into new species natural selection and its evolutionary consequences provide a scientific explanation for the fossil record of ancient life-forms as well as for the molecular and structural similarities observed among the divers species of living organisms beneficial traits are retained and passed on to subsequent generations traits with low survival value diminish!

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11 how did darwin use finches to determine that natural selection led to the origin of new species ·first darwin established that the species were related to individual ·he determined that each finch had a found on its particular island uniquely beak islands food a adapted to the kind of body ·the finches were different species but they all looked very similar this gave him the idea that somehow in this 1 these different species could have been formed from a small number of common ancestors so that each was modified to suit different ends geographic isolation he proposed that originally a few seed-eating finches had flown to the islands from the mainland over millions of years the finches had adapted to the foods available on each island adaptive radiation emergence of many species from a common ancestor that was introduced to a new environment 2 behavioral isolation can occur when two populations are capable of interbreeding but have differences in courtship rituals or other types of behaviors 3 form of reproductive isolation in which two populations ex different bird songs temporal isolation reproduce at different times not mixed isolation means that traits are so populations can become from each other very different

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12.what are some examples of observed natural selection that have occurred recently a industrial melanism the peppered moth as increased pollution darkened the trees there was found in light wooded forests in england an increase in of dark moths b insecticide resistance in insects widespread use of ddt increase number of insects resistant c resistance to penicillin in bacteria more widespread use of antibiotics increase number of antibiotic resistant bacteria the traits were already present insecticides and penicillin acted as being resistant is now a trait with high survival value m.r.s.a environmental selecting agents 3.1 h the variation of organisms within a species increases the likelihood that at least some members of the species will survive under changed environmental conditions d finch research 1977 drought food supply decreased total bird population went from 1200 ­ 800 geospizia fortis medium ground finch the grants the ancestors tale p260 surviving members of this species were all 5 larger than those who died 10.68 mm 9.42 mm average beak length before average beak depth before average beak length after average beak depth after 11.07mm 9.46mm these types of beaks are more efficient at obtaining the big tough spiky seeds of the weed tribulus about the only seed found during a drought.

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