Monday, January 30, 2012
Thursday, January 26, 2012
- Evolution of finches on Galapagos Islands: the islands were colonized by finches that strayed from the South American mainland.
- Pesticides-do not create resistant individuals, but selects for resistant insects that were already present in the population.
- 2 populations of trees are separated by a river (particularly isolated from each other). Trees are more likely to breed with members of the same population on the same side of the river. Each side of trees could evolve different traits.
- A piece of patterned fabric (artificial environment)
- 10 different colors of construction paper
- Petri dish
Wednesday, January 25, 2012
Today we took notes during class.
The notes that we took today were about Darwin, his theory, and some of the other biologists.
A few things to know about Darwin (1809-1882)
- he introduced the theory that all life is connected
- he was one of the most influential scientists in the development of modern biology
- published the Origins of Species- there are two main points to his book- "decent with modification" or evolution, and natural selection
- he became a naturalist at 22 for a voyage around the world on the ship the HMS Beagle
- he was mainly in the Galapagos Islands
- while of the voyage he collected many specimens and noticed that as the animals strayed from the mainland, they began to adapt
- he also found that after many generations, two populations could slowly adapt and change so much so that they eventually became two different species
Darwin explained the adaptations through natural selection and had 3 main points- overproduction, variation, and reproductive success. He also looked at artificial selection and came to conclude that by modifying a species through breeding would end up with the offspring or flowers/vegetables not looking like their ancestors. Artificial selection is when the species is being selected for certain traits and combined to get the desired offspring.
Many scientists during Darwin's day thought that the earth was relatively young, and was full of unrelated species. A few of the scientists to know from his time are-
-Anaimander(Greek)- thought all life arose in water and simpler forms preceded the more complex ones
-Aristotle(Greek)- thought species did not evolve (static)
-Buffon (1700's french)- thought world was much older than 6000 years, and that a species in a fossil could be an ancient version of a living species
-Lamark (1800's french)- said life evolved through adaptation, but had a strange theory on how life evolved. He believed the "Inheritance of Acquired Characteristics" was how life evolved. So if you don't use a limb, then you will pass that on to your offspring and that offspring won't have that limb. So if you didn't ever use your thumb, then your child wouldn't have a thumb.
-Lyell (Scottish)- earth was old and he supported the gradualism principle
-Wallace (British)- developed idea of natural selection identical to Darwin's, but Darwin published his first, so Wallace isn't as well known
Examples that support evolution:
- The fossil record- fossils can be used to research organisms from the past and are preserved in rocks. In the rocks, you can see different layers, and each layer is a different time period, as you dig further down, the fossils become older. Some of the oldest fossils are about 3.5 billion years old. The people who study these fossils are called paleontologists.
- Biogeography- the geographic distributions of species. ex. the animals that are found in Australia are found almost exclusively in Australia because it's isolated by the ocean.
- Comparative Anatomy- similar structure, but with different functions, and indicates that certain species came from a common ancestor (homology),vestigial organs or homologous structures can help trace back to a common ancestor, like in some animals such as the whale.
- Comparative Embryology- comparison the organisms while they are developing
- Molecular Biology- a common genetic code shared by organisms ex. there is less than a 2% difference in human and chimp DNA.
Over production of offspring, individual variation, and differential reproductive success all lead to adaptive evolution.
- UP pg. 19-20
- UP pg. 5 and pg. 13-16 are both due Monday
- If you haven't read the Darwin article, CH 1, and CH 13
Monday, January 23, 2012
- Recieved the scedule, UP, notes, Darwin packet, and lab 38
- Watched video clips about evolution
- Answered the questions on UP 7-8 (see below)
You can view the videos at: http://www.pbs.org/wgbh/evolution
Then type the video titles in the convenient little search box in the top- right corner of your screen, and find the link to the video. Note: You need quicktime to see the videos, and the subtitles are really useful!
Video 1: Isn't Evolution Just a Theory?
Question: Is it correct to say that evolution is JUST a theory?
- Charles Darwin pioneered the idea that all life is connected, and the theory of natural selection
- Theories pull together observations to create "rules" for how the universe works
Video 2: Who was Charles Darwin?
Question: Why was Darwin considered a "Revolutionary"
- Darwin's work was highly controversial because it contradicted many established religious and scientific beliefs at the times
- In order to prove his theories, he traveled the world and carefully documented life's great diversity, then analyzed the patterns
Video 3:How do we know that evolution happens?
Question:Describe the transitional fossils associated with whales.
- The evolution of species can be plotted on an evolutionary timeline, which chronologically shows the changes ancient species went through in order to evolve into modern species
- An ancient species that shares common traits with a modern one, and has no similar, discernable ancestors, may be the original ancestor to modern species
- As time passes, the ancestor changes and adapts and become more similar to modern species
Video 4:L How does evolution really Work?
Question: Describe the process of natural selection and how it effects hummingbird populations.
- Genetic Variation: different individuals within a species express different traits, some more favorable than others
- Overproduction of offspring: more offspring are produced than the number that can survive
- Struggle for existence: The overload of individuals compete for resources
- Differential survival and reproduction: Individuals without favorable traits are at a disadvantage for obtaining necessary resources. These individuals die. Those left have more favorable traits and have a higher chance of reproduction, so the favorable traits are inherited by the next generation.
Video 5: Did Humans Evolve?
Question: Explain how DNA sequences are used to provided eveidence of a commoon ancestor?
- Humans did not eveolve form chimapnzees, but both species shared a common ancestor
- Humans and primates have similar DNA, which helps prove this relationship
- If two species share the same gene sequences, aside from a few mutations, they are related
- Physical trait similarities, fossil evidence, and DNA similarities prove common ancestry
Video 6: Why does evolution matter now?
Question: Why is the theory of evolution an important theory for doctors and the field of medicine? How does the theory affect the way illnesses and treatments are approached?
- Some microbes can evolve to become resistant to antibiotics, which is very dangerous
- If one drug does not kill ALL of the microbes, the remaining resistant microbes reproduce and form an entire population of microbes resistant to a drug. Thus, they have evolved to evade our killing, which can result in difficult to cure diseases.
- In result, multiple drugs are often prescribed
Homework is on Google Docs (hint- read chapter 13, chapter 1 p. 8-13, the Darwin packeet, and begin on UP 5)
Meet in computer lab tomorrow!!!!!!!
Maddy is the next scribe
Tuesday, January 3, 2012
After we got back from winter break, we quickly dove into our next topic, THE MIRACLE OF LIFE!