Part 1: Evidence from the Fossil Record Fossils provide solid…

Question Answered step-by-step Part 1: Evidence from the Fossil Record Fossils provide solid… Part 1: Evidence from the Fossil RecordFossils provide solid evidence that organisms from the past are not the same as those found today. They also show the progression of evolution through the eons. In fact, scientists have found fossils dating back as far as 3.5 billion-years! These fossils are of ancient photosynthetic prokaryotes which is amazing as there are no hard surfaces in a single celled organism, which are the structures that are most commonly fossilized and survive over time. After carefully collecting and analyzing fossils from all over the globe and from all types of organisms, scientists have been able to place them with across the geologic timescale – the history of the earth that is. Studying the mass extinctions of organisms and changes in fossil composition has also allowed scientists to conclude when major globe wide events have happened. Geologic Timescale:Divisions of the TimescaleNotice that the timescale divides Earth’s history into eons, eras, periods and then epochs. There are four eons with three having past and currently it being the Phanerozoic eon, all together spanning the largest amounts of time individually. The epochs spanning the shortest amount of time individually. Also notice that the periods of the Cenozoic era are divided into epochs, illustrating how more attention has been given to the evolution of primates and flowering plants than earlier organisms.Use the Geologic Timescale below to answer the following questions. Why do you think that you read the timescale from the bottom, starting at the oldest time, and moving up to the more recent? How many million years did the Precambrian era span?Paleozoic _____Mesozoic _____Cenozoic _____Which era was the longest? ___________   Does it have many organisms occurring during its time? ________________________ When were the first shelled organisms present? ___________Most of the coal that we burn today was formed from the great coal forming swamps and forests in the ________ period which was ________ million years ago. What period and epoch are the age of the Homo sapiens? _________Image transcription textHolocene 0.01-present life Human influence on plant Age ofHomo sapiens Quaternary Significant Mammalian Pleistocene1.8-0.01 Herbaceous plants Extinction – Precense of… Show more… Show more Figure 1: Geologic Timescale of Earth’s history. Adapted from image at https://www.nps.gov/subjects/geology/time-scale.htm Licensed by CC BY-SADating with the Timescale:When you use the timescale, you are use relative and absolute dates. For example, if you say that the first dinosaurs appeared in the Triassic period you are using relative time, but if you use give the date in 199.6 -145.6 MYA (millions of years) you are using absolute dates. So how can scientist obtain absolute dates for organism that have been deceased and fossilized for millions of years? They do this by measuring the amount of radioactive isotope in the rocks surrounding the fossils. This is called radiometric dating. Watch this video to see how radioactive dating is done: Carbon-14 Dating (For fossils older than carbon’s half-life will last, we can use other radioactive isotopes) Fossils:Fossils are traces of organisms that lived in the past. When fossils are found, they are analyzed to determine the age of the fossil. The absolute age of the fossil can be determined though radiometric dating and determining the layer of rock in which the fossil was found. Older layers are found deeper within the earth than newer layers.The age and morphologies (appearances) of fossils can be used to place fossils in sequences that often show patterns of changes that have occurred over time. This relationship can be depicted in an evolutionary tree, also known as a phylogenetic tree. Activity:  Analyze the fossils below which belong to the modern-day horse, Equus and its ancestors. Answer the questions.Give two similarities between each of the skulls that might lead to the conclusion that these are all related species.  Looking at the skull, what is the most dramatic change from the early horse to the modern horse?  What is the most noticeable change in the leg anatomy that occurred from the early horse to the modern horse?Image transcription textEquus (modem horse) Pliohippus (one-toed horse) MerychippusMesohippus Eohippus (early horse) The diagram above shows thechanges over time in the horse. Evidence for these chan… Show more… Show moreFigure 2: Evolutionary history of the horse as told by the fossil record. CC BY NC SAWhy you think that the modern horse is so much larger than the early horse? What evolutionary adaptations might it have that allow it to reach this size?   Science Biology BIOL 1408 Share QuestionEmailCopy link Comments (0)