science1.A branch of knowledge dealing with a body of facts or truths systematically arranged.2.Systematic knowledge of the physical or material world gained through observation and experimentation.3.Knowledge, as of facts or principles; knowledge gained by systematic study.
the unknown pastScientists who study the past need to usedifferent methods than those who study thingsthat are observable.They are like detective, putting clues together,trying to paint a picture of what occurred. Theyuse what they know about the evidence and whatthey know about cause-and-effect relationships.
How do we test something that occurredin the past? something that occurs veryslowly?
We must use historical science todetermine what happened in the past.
historical scienceWhen you lay on the couch to take a nap, the sun is shining brightly.
historical scienceYou awake and look outside. evidence 1: the driveway is covered in water and evidence 2: the car in the driveway is also wet
historical science What can you conclude? it rained while you slept or the automatic sprinklers came on
historical scienceBut then you see the following: evidence 3: the lawn and the street are perfectly dry and evidence 4: there are no clouds in the sky
historical science Now what? Rain storm and sprinkler are still possible but are less likely because of evidences 3 and 4 (lawn dry & no clouds)
historical scienceYou look at bit harder and see evidence 5: a bucket with soapy water and a sponge behind the car
historical science Now with the last piece of evidence (the soapy bucket), it is much more obvious: Someone washed the car.
historical science This is an example of making an guess about the past using historical reasoning. You missed what happened, because you were asleep, but there remains some clues.
historical scienceUsing those clues, yourjob is to come up with the best explanation. You start with the evidence and with other knowledge you have about the world. You work backwards to infer what probably happened when you were not there to observe it.
historical science The best explanation will be the one that explains most of the evidence.
What are the various viewpoints on theorigin of species?
creationism a doctrine or theory holding that matter, the various forms of life, and the world were created by God out of nothing and usually in the way described in Genesis
intelligent design The theory of intelligent design holds that certain features of the universe and ofliving things are best explained by anintelligent cause, not an undirected process such as natural selection.
evolutionBiological evolution is descent with modiﬁcation.
evolution This deﬁnition encompasses small-scale evolution, microevolution - changes in gene frequency in a population from one generation to the next and...
evolution...large-scale evolution macroevolution - the descentof different species from a common ancestor over manygenerations.
evolutionBiological evolution is not simply a matter of change overtime. Lots of things change over time: trees lose theirleaves, mountain ranges rise and erode, but they arentexamples of biological evolution because they dontinvolve descent through genetic inheritance.
evolutionThe central idea ofbiological evolution is thatall life on Earth shares acommon ancestor.Through the process ofdescent withmodiﬁcation, thecommon ancestor of lifeon Earth gave rise to thediversity of the variousspecies.
who was the main person to put evolution on the table?charles darwin What book did Darwin write explaining his theory of evolution? On The Origin of Species
darwin’s theory:evolution through natural selection Darwin studied 13 species of ﬁnches. They were all similar, except for their: body size beak shape eating habits
darwin’s theory:evolution through natural selection Darwin thought the varieties of plants and animals could be best explained by descent from a common ancestor. He used the plants and animals of the Galapagos Islands as an example.
darwin’s theory:evolution through natural selectionThe mechanism Darwin thought that was responsible forevolution was Natural Selection.He argued that it had the power to make new forms oflife.
natural selection Darwin’s idea became known as the Theory of Evolution by Natural Selection. Natural Selection means that organisms with traits best suited to their environment are more likely to survive and reproduce. Overtime, as new data was gathered and reported, changes were made to Darwin’s original ideas about evolution by natural selection.
principles of natural selection1. Organisms produce more offspring than can survive.2. Differences, or variations, occur among individuals of a species.3. Some variations are passed to offspring.4. Some variations are helpful. Individuals with helpful variations survive and reproduce better than those without these variations.5. Over time, the offspring of individuals with helpful variations make up more of a population and eventually may become a separate species.
adaptationAn adaptation is anyvariation that makes anorganism better suitedto its environment.
adaptation Over time, the genetic makeup of a species might change its appearance. Many kinds of environmental factors help bring about changes. When individuals of the same species move into or out of an area, they might bring in or remove genes and variations.
variations A variation is an inherited trait that makes an individual different from other members of its species. Variations result from mutations. Some gene changes produce small variations, such as differences in the shape of human hairlines. Other gene changes produce large variations, such as an albino animal in a population of normal colored animals. If individuals with these variations continue to survive and reproduce over many generations, a new species can evolve.
darwin’s theory has evolved Darwin did not understand genetics, like you do. He did not know how traits are passed from one generation to another. Once scientists learned more and more about genetics and mutations, Darwin’s Theory was modiﬁed. The modern theory is called neo-Darwinism.
neo-darwinismThe theory of evolutionbased on Darwin’soriginal theory ofevolution of speciesthrough the process ofnatural selectiontogether with currentunderstandings andtheories of genetics andinheritance.
which theory is right?There still remains much debate over the origin ofspecies.Sometimes the evidences can be explained inmore than one way -- this is where differenttheories and debates are made.The claims of the theories cannot be tested, butby looking at all the evidence carefully, we candecide which theory seems more logical.
which theory is right?Our goal, grade 8 students, is to examine thescientiﬁc evidences and make our owneducated decisions on the origin of life.
A particular slide catching your eye?
Clipping is a handy way to collect important slides you want to go back to later.