Common Ancestry
Key Concept The Theory of Universal Common Ancestry suggests that organisms on Earth evolved from a single common ancestor. Scientists construct diagrams & charts to show how seemingly diverse species share common traits.
Vocabulary ancestry: the lineage or bloodline of descendants cladograms: diagrams that show the relationships of organisms evolution: change in living organisms over long periods of time fossil: the preserved remains of an organism species: distinct group of organisms that can produce living offspring
Charles Darwin On the Origin of Species Published in 1859 Proposed a theory that all life developed gradually (over 600 million years) from different, much simpler, parent organisms. Proposed that weaker, less adaptable members of a population died without reproducing & that the strongest members of a population passed on traits to the next generation
Charles Darwin On the Origin of Species Scientists have since confirmed that each population of organisms changes over time. Darwin proposed that over many generations a group of organisms could evolve different traits than were present in the original population. So many changes could occur that a new species could be created. We call this process evolution.
Fossils What can be a fossil? Part of the organism (bones, teeth, shells) A trace of the organism (Imprint of a leaf or a footprint) Something left behind by the organism (animal droppings)
Fossils Why are Fossils Important? Fossils provide a snapshot of life on earth over time. Scientists are able to find evidence of evolution from fossil records. Sedimentary Rock forms layers that represent different geologic time periods. Scientists can look at the layers and see that new species appeared at different points in time.
Think About It Two organisms that are able to produce live offspring are considered a. List two species that are similar and think may have evolved from the same parent organism. What traits do they share?
The Theory of Universal Common Ancestry (UCA) Where did the Theory of UCA come from? Charles Darwin s On the Origin of Species 1859 What is the Theory of UCA? A theory that all organisms that have ever lived on Earth descended from a single primitive ancestor.
The Theory of Universal Common Ancestry (UCA) Scientists have developed tests to determine the relatedness of species. Scientific evidence links all three domains of life. 1. Eukarya (humans, animals, plants, yeast ) 2. Bacteria 3. Archaea Scientists believe the first form of life on Earth was a simple, single-celled organism that lived in water.
Think About It 1. The Theory of Universal Common Ancestry (UCA) states that: a. all humans are related to one another b. all life originated from a single organism c. all life has slowly changed over time d. all species that look similar are related to one another 2. What evidence has been found to support UCA?
Cladograms The evolutionary relationship of organisms can be studied using a method called cladistics. Cladistics is the systematic method for making & testing predictions about evolutionary relationships among organisms.
Cladograms Steps to Building a Caladogram 1. Choose a group of organisms to compare. (Lamprey, Shark, Salamander, Lizard, Tiger, Gorilla, Human)
Cladograms Steps to Building a Caladogram 2. Construct a table with the name of each organism across the top and some structural features you want to compare listed in the first column.
Cladograms Steps to Building a Caladogram 3. Construct a cladogram. Each organism that is listed to the Right of the trait have that trait. Now we can see where species diverge from one another. And also, which species are most closely related.
Vocabulary Review ancestry arrange cladogram evolution fossil species 1. When we examine the of an organism, we examine the whole line of descendants. 2. A(n) is a diagram of the evolutionary relationship of organisms. 3. A group of organisms that produce live, fertile offspring is called a. 4. The theory of was that living organisms will change over time. 5. A(n) is a preserved remains of an organism. 6. It is useful to data in a table in order to see relationships between organisms.
Vocabulary Review ancestry arrange cladogram evolution fossil species 1. When we examine the ancestry of an organism, we examine the whole line of descendants. 2. A cladogram is a diagram of the evolutionary relationship of organisms. 3. A group of organisms that produce live, fertile offspring is called a species. 4. The theory of evolution was that living organisms will change over time. 5. A fossil is a preserved remains of an organism. 6. It is useful to arrange data in a table in order to see relationships between organisms.
Other Theories on the Beginning Life http://m.livescience.com/13363-7-theories-origin-life.html
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