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OK, to help you to update your knowledge about the REAL world to the 20th century, let's look at some figures in the Environmental Biology textbook, or in the General Biology book.
EVOLUTION (brief lecture by the instructor)
Evolution (def. Am. Heritage Dictionary) n.(Biology) The scientific theory that populations of organisms change with passage of time
so that descendants differ morphologically and physiologically from their ancestors.
If the dinosaurs had not gone extinct humans would not be here
A common misconception by people who don't understand evolution is that the giraffe lengthened the neck by stretching to reach tree leaves, and then passed on this "acquired" trait of longer neck to their offspring. However, that is like saying that if human parents play a lot of tennis their kid will acquire better tennis abilities and become a tennis pro. Obviously, it doesn't work that way. Instead giraffes that happened to be born with the "genetic" trait for longer necks were more successful in the struggle for survival, produced more offspring, and passed on the trait for long necks to their offspring (long necks are inherited). In humans, only parents with the right genes for tennis may give birth to kids with professional quality tennis playing genes (athletic abilities are inherited). (The figure is in the Environmental Biology textbook.) (Figure used for educational purpose, from Cunningham, Cunningham, and Saigo. 2007. Environmental Science: A Global Concern, ed. 9. McGrawHill, Higher Education, Boston. Textbook used by this instructor in Environmental Biology at the time the web page was created. See copyright and fair use notice below.)
 How evolution really works In the words of the person posting the video below: "The world is full of misinformation. Denying the facts doesn't change reality. Many of those who claim evolution is wrong has no understanding of what evolution really is." View the mathematical approach to mutations and natural selection -- mechanisms of evolution -- in the videos below. Both videos are rather "technical", and they are mainly posted to show that evolution has a factual base -- not based on "magic" or the "supernatural" as creationism and/or intelligent design. Enjoy!Part I Part II |
Another common misconception is that INDIVIDUALS can evolve. Not so. Only populations evolve. YOU do not evolve. The Human species evolve generation after generation. Two populations of the same species living in different areas with different environments, after being separated by some kind of geographic barrier, might evolve in different directions due to different adaptations to the different environments. The figure above is from the Environmental Biology textbook. "During cool, moist glacial periods, what is now Arizona was forest-covered and squirrels could travel and interbreed freely. As the climate warmed and dries, desert replaced forest on the plains. Squirrels were confined to cooler mountaintops, which acted as island refugia, where new, reproductively isolated species gradually evolved." (Figure used for educational purpose, from Cunningham, Cunningham, and Saigo. 2007. Environmental Science: A Global Concern, ed. 9. McGrawHill, Higher Education, Boston. Textbook used by this instructor in Environmental Biology at the time the web page was created. See copyright and fair use notice below.) Yet another misconception (related to the squirrel figure above) is that there is no evidence of new species formed -- the last step in the natural selection process. Not so. There is plenty of evidence for new species formation. The squirrel example above is just one (Squirrels separated by Grand Canyon evolved into two different species.), but the list is long. A statement by a skeptic was discussed by James Merritt:This is bogus. We've seen it happen naturally without our tampering with the process. ...
'Three species of wildflowers called goatsbeards were introduced to the United States from Europe shortly after the turn of the century. Within a few decades their populations expanded and began to encounter one another in the American West. Whenever mixed populations occurred, the species interbred (hybridizing) producing sterile hybrid offspring. Suddenly, in the late forties two new species of goatsbeard appeared near Pullman, Washington. Although the new species were similar in appearance to the hybrids, they produced fertile offspring. The evolutionary process had created a separate species that could reproduce but not mate with the goatsbeard plants from which it had evolved.'
The article is on page 22 of the February, 1989 issue of Scientific American. It's called 'A Breed Apart.' It tells about studies conducted on a fruit fly, Rhagoletis pomonella, that is a parasite of the hawthorn tree and its fruit, which is commonly called the thorn apple. About 150 years ago, some of these flies began infesting apple trees, as well. The flies feed and breed on either apples or thorn apples, but not both. There's enough evidence to convince the scientific investigators that they're witnessing speciation in action. Note that some of the investigators set out to prove that speciation was not happening; the evidence convinced them otherwise."
Taxonomists classify organisms according to evolutionary relationships, into three domains: Bacteria, Archaea, and Eukarya. Figure 4.8 in the Environmental Biology textbook shows an evolutionary (phylogenetic) tree of the major groups (domain and kingdoms) of living organisms on Earth. The domain Eukarya is further divided into four kingdoms: Protista, Plantae, Fungi, and Animalia. All groups have common ancestry. All organisms on Earth are related, and have a common evolutionary line back to the start of life on earth about 4 billion years ago. "Modern techniques for DNA sequencing and protein analysis give us a molecular record that shows both relationships between groups and timing of evolutionary events. This evidence allows us to construct a phylogenetic map from bacteria to flowering plants and humans." (Figure used for educational purpose, from Cunningham, Cunningham, and Saigo. 2007. Environmental Science: A Global Concern, ed. 9. McGrawHill, Higher Education, Boston. Textbook used by this instructor in Environmental Biology at the time the web page was created. See copyright and fair use notice below.)
The cartoon dated 1927 -1938 is used for educational purposes by Dr. Nilsson, South Texas College, reposted here, from http://www.ucl.ac.uk/sts/cain/projects/ejn/ejn_comics/. For further source information and fair use statement see bottom of page.
Human Evolution: The Evidence The person posting the video said: "Oversimplified evidence for human evolution. There are a few spelling mistakes... 'coincedence'? (that's what I get for making videos at 2:00 am." View the video below. Enjoy! Make sure you have the sound on so that you can enjoy the music! |
Evolutionary tree of humans. "Note that modern humans are the last remaining species of a group that was once highly diverse and consisted of several species that coexisted."
Humans and the Chimpanzee have common ancestry. We had a common evolutionary line that separated about 5 million years ago. In the squirrel figure above we said that two populations of the same species living in different areas with different environments, after being separated by some kind of geographic barrier, might evolve in different genetic directions due to different adaptations to the different environments. That is what happened to the common ancestor of Man and Chimp (the Pygmy Chimpanzee). One difference between present day chimpanzees and humans is that we have 46 chromosomes (or put in another way 23 distinct chromosomes in the human egg or sperm), while chimpanzees have 48 (or 24). This chromosomal difference is sometimes used by people lacking science education who say, "see how different we are, we even have different number of chromosomes". But scientists have already investigated this and found that the human chromosome number 2 is a fusion of two ancestral chromosomes. (Also read this.) As stated earlier, in an attempt to answer questions by a student, in order for humans to become bipedal we had to sacrifice certain physical characteristics such as a much easier and "better" birth in our common ancestor with the chimpanzee, because of skeletal changes needed for us to become bipedal. The population that eventually evolved into Chimps continued to live in the rainforest, while the population that eventually evolved into Humans was exposed to a new grassland environment. This new environment eventually led to bipedalism and that gave us the ability to move around better -- move out of Africa. The rest is history...
(Figure used for educational purpose, from Belk and Borden. 2004. Biology. Pearson Education, Inc., Upper Saddle River, New Jersey. Excellent textbook considered for use by this instructor in non-majors introductory biology at the time the web page was created. See copyright and fair use notice below.)|
Ken Miller on Apes and Humans. |
The cartoon dated 1927 -1938 is used for educational purposes by Dr. Nilsson, South Texas College, reposted here, from http://www.ucl.ac.uk/sts/cain/projects/ejn/ejn_comics/. For further source information and fair use statement see bottom of page.
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We are all related. We are all related. Is it really that hard to see? View the video. Enjoy! |
Evolution of humans. Skull fossil record of humans. The ape-to-human transition shows a change from many apelike characteristics (large jaw, small brain case, receding forehead), to more human characteristics (reduced jaw, larger brain case, smaller brow ridge). (Figure used for educational purpose, from Belk and Borden. 2004. Biology. Pearson Education, Inc., Upper Saddle River, New Jersey. Excellent textbook considered for use by this instructor in non-majors introductory biology at the time the web page was created. See copyright and fair use notice below.)
"It is therefore probable that Africa was formerly inhabited by extinct apes closely allied to the gorilla and chimpanzee; as these two species are now man's closest allies, it is somewhat more probable that our early progenitors lived on the African continent than elsewhere." (Charles Darwin, The Descent of Man -- 1871). Although no African fossil apes or humans were known at the time, remains recovered since then have largely confirmed his sage prediction about human origins. (Planet of the Apes. http://www.primates.com/history/index.html)
"The earliest known hominid in the fossil record is the man-ape Australopithecus afarensis. When A. afarensis lived in the savannas and woodlands of Africa five to three million years ago, it was, so far as the evidence shows, the only species of its kind. ... It s cranial capacity was no greater than that of modern chimpanzees. But the stage was set for the evolutionary advance toward humankind." "As time passed, to no later than two million years ago, the early man-ape populations both evolved and split into at least three distinct species. Two of the species, the advanced man-apes Australopithecus boisei and Australopithecus robustus, were 1.5 meters (five feet) tall, with gorilla-like bony crest down the middle of the skull that anchored enormous jaw muscles. ... The third specie derived from the primitive man-apes, Homo habilis, was more nearly a true human in the contemporary sense, enough for anthropologists to remove it from the genus Australopithecus and place it in Homo. It stood just under 1.5 meters and weighed about 45 kilograms (100 pounds). Its for was essentially that of modern H. sapiens, with one outstanding exception: the brain volume was ... still only half as much as in modern H. sapiens but considerably larger than in chimpanzees." "During the next million years the man-apes disappeared ... [possibly driven to extinction by H. habilis ... What followed was mostly the evolution of a single species, traversing the series H. habilis to H. erectus to H. sapiens] ... H. habilis survived and continued to evolve ... into the intermediate species Homo erectus. Sometime during its early history H. erectus expanded its range from Africa to Europe and Asia." "Across the far-flung H. erectus populations of the old world, the brain size and dentition progressed to essentially modern levels, by half a million years before present. The chronospecies H. sapiens, or the modern species derived from archaic species by vertical evolution, had arrived."(Edward, O. Wilson. 1992. The Diversity of Life. W.W. Norton & Co., New York. 424pp.)
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Human Evolution: The fossil record The poster of the video said, "Time after time I hear the claim from creationists that there are no transitional fossils in general, let alone between apes and humans. This is so jaw-droppingly absurd that I decided to make a video showing some hominid fossils."
View the video below. Enjoy! |
Evolution of the horse. The fossil record of the horse (which stretched back about 50 million years) shows a change, from a small, short horse living in a forested area, with short legs for moving in a forest, having many toes, and teeth shaped for eating shrubs, to a larger, tall horse living on the grass plains, with long legs for running on the grass plains, having one toe, and teeth modified for grazing. (Figure used for educational purpose, from Belk and Borden. 2004. Biology. Pearson Education, Inc., Upper Saddle River, New Jersey. Excellent textbook considered for use by this instructor in non-majors introductory biology at the time the web page was created. See copyright and fair use notice below.)
The cartoon is used for educational purposes by Dr. Nilsson, South Texas College, scanned, from The Monitor, McAllen.
Extinction of the dinosaurs. A lecture on evolution must include the dinosaurs. Giant reptiles roamed the earth for 200 million years until, as the most accepted theory states, an asteroid hit Mexico's Yucatan coastline and caused the extinction of the dinosaurs 65 million years ago. This is the most commonly discussed theory as to what happened to the dinosaurs. Although some religious groups claim that this never happened and that dinosaurs and humans at some point in time existed together, and that dinosaurs was on board Noah's arc. The truth is that if the dinosaurs had not gone extinct humans would not be here -- human evolution would never have taken place.|
Dilbert - Extinction of the dinosaurs For a smile (?) view the Dilbert video cartoon. The cartoon is short, 13 seconds, so downloading is will not take long. (0:13 min. However, still best if you have fast Internet connection. Sometimes these YouTube links disappear. Please let the instructor know if this happens.) Enjoy! |
Town Hall Topic
If the dinosaurs had NOT gone extinct, would we (humans) be here? This is a very interesting topic. Would we be here, or would the dinosaurs have suppressed the mammalian evolution preventing the evolution of humans?
Figure is used for educational purposes by Dr. Nilsson, South Texas College, scanned, from Starr and Taggart. 1995. Biology: The Unity and Diversity of Life, ed. 7. Wadsworth Publishing Company. p. 338.
The truth is that if the dinosaurs had not gone extinct humans would not be here -- human evolution would never have taken place.
Figure is used for educational purposes by Dr. Nilsson, South Texas College, scanned, from Starr and Taggart. 1995. Biology: The Unity and Diversity of Life, ed. 7. Wadsworth Publishing Company. p. 339.
We have established that biological evolution is the scientific theory that populations of organisms change with passage of time so that descendants differ morphologically and physiologically from their ancestors. To proceed to chapter 6 click on the link in the left frame or click here. Copyright © 2005, 2006, 2007, 2008, 2009, Jan A. Nilsson. Page created 10.IX.2005, last updated 19.VIII.2009, most likely during the wee hours of the morning on a G3 PowerBook owned by Jan A. Nilsson. Web page layout and design © and intellectual property Jan A. Nilsson. Content on Dr. Nilsson's CyberOffice may not be used for commercial purposes. All rights reserved. Except for educational purposes and 'fair use' (see below), reproduction of the whole or any part of the contents without written permission is prohibited. If used for educational purposes and 'fair use', including photographs, source must be given. (Some clip art, texts and backgrounds used on Dr. Nilsson's CyberOffice downloaded for educational purposes and/or 'fair use' from Internet free domain has no source.)
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