Biology Notes Evolution Part 3 Pages 320-363

Standards 6.7 ____ Describe the scientific explanations of the origin of life on Earth ____ Explain the evidence supporting the scientific theory of the origin of eukaryotic cells (endosymbiosis) ____ Identify basic trends in hominid evolution from early ancestors six million years ago to modern humans, including brain size, jaw size, language, and manufacture of tools 6.8 6.14

Essential Questions: How does science help us explain how all 1. 2. life, including us, came to be? 1. 2. How does the evidence used to support evolution help us connect past life forms to those living today?

I. Evidence of Evolution One of the oldest questions scientists have is how ____ on Earth began. ________ provide the majority of evidence for the ______ of life on Earth. Remember, fossils are formed in ___________ rock Scientists can use ______ fossils or ___________ decay to date the fossils and gain an estimate of exactly how ____ the Earth is as well as when certain __________ existed life Fossils origin sedimentary index radioactive old organisms

index fossils = distinct fossils with a known date of existence used to _________ to fossils with an unknown date of existence compare

radioactive decay = calculating the age of a sample based on the amount of ___________ isotopes found within that sample Through the discovery of _______, scientists were able to construct a ___________ time scale which divides Earth’s history into major _____ and ________ radioactive fossils Geological eras periods

II. The Origin of Life: Fact vs. Fiction Spontaneous Generation Hypothesis = the hypothesis that _______ could arrive from non-living matter Generally this idea was accepted until _____ when Francesco _____ performed his meat and fly experiment concluded that ____ came from ________ and were not spontaneously generated summarizes his findings with the theory that ____ can only come from other life matter 1668 Redi flies maggots life

B. Organic Molecule Hypothesis The Earth is believed to be ____ billion years old caused by a giant “collision” of _______ particles elements within this cosmic debris settled according to their _______ which formed the core parts of the Earth and its atmosphere during this time, the Earth’s atmosphere was very unstable and contained very little _______ mostly there was ____, _____, ___, ____, and ______ (vapor) 4.6 cosmic Big Bang Theory density oxygen CO CO2 N2 HS water

____ billion years ago, scientists believe conditions occurred that allowed the Earth’s surface to cool large formations of ______ to appear (the earliest ____________ rocks date back to this time) water is crucial to life because it is needed to make life’s _________ organic molecules 3.8 water sedimentary essential ** lipids, carbohydrates, nucleotides, proteins

In 1953, Stanley ______ and Harold ______ tried to recreate Earth’s early atmosphere to see how the evolution of organic molecules could occur Miller and Urey were successful in producing _______ acids which showed that ________ can arise from __________ molecules Miller Urey amino organic inorganic

C. Meteorite Hypothesis In 1969, a meteorite that fell in _________ contained ______ acids, so perhaps organic molecules have _______ existed Australia amino always

III. Milestones in the Formation of Life on Earth ____ BYA = water formation; formation of many of life’s _________ molecules _______ BYA = proteinoid microspheres appear; _____ evolves from RNA (hypothetical) the first ___________ are observed in these microspheres 3.8 essential 3.8-2.5 DNA membranes

____ BYA = prokaryotic microfossils appear (fossil evidence) ____ BYA = Earth’s atmosphere becomes ___________ (due to ______________ ) this allows for _______ respiration to occur ___ BYA = prokaryotes develop internal membranes; rise of ___________ 3.5 2 oxygenated photosynthesis cellular 1.5 eukaryotes

endosymbiotic theory = the theory that states how __________ cells are formed from ___________ organisms living together this is given critical support in the _______ when Lynn Margulis compared ___________ and mitochondria to free living ___________ eukaryotic prokaryotic 1960’s chloroplast prokaryotes

once __________ organisms appeared, scientists believe the process of _______ reproduction ____ MYA = Paleozoic ____ shows first multi-cellular ___________ followed by __________ and finally the _________ era (see Geologic time scale) eukaryotic sexual 254 era organisms Mesozoic Cenozoic

IV. Hominid Evolution History and fossil evidence indicates that the ________ line of primates appeared approximately __ to __ million years ago Primates are a class of organisms that have binocular ______, a well developed _____, relatively long _______ and toes, as well as arms that can ______ Hominids are classified by their ability to _____ upright (_______), have an __________ thumb, and have developmentally larger __________ hominid 6 7 vision brain fingers rotate walk bipedal opposable cerebrum

Major Hominid Milestones: Genus Australopithecus 3.8-3.6 mya: earliest known hominid divergence; walk bipodal; evidence _____ Homo habilis 2.5 mya: first use of _____ (handy ____) Lucy tools man

Homo erectus 1.75 mya: larger ________; downward facing ________; believed to have originated in Africa and migrated to the Middle East Homo neanderthalensis 500,000 years ago: originating out of _________; evidence of living in social _______ Homo sapiens 100,000 years ago: originating out of Middle East and Africa; body like that of modern ________ cerebrum nostrils Germany groups humans

Human _________ has been strongly influenced by culture Human _________ has been strongly influenced by culture. Instances include larger brains with smaller jaw lines which allowed capabilities of more _________ languages. The ability to walk upright and opposable thumbs led to increasingly sophisticated use of ______. evolution complex tools Australopithecus afarensis Homo habilis Homo neanderthalensis Homo sapiens