Evolution

Hi. Well today during class we finished up the PowerPoint from yesterday and we also did about 2 slides from today’s PowerPoint. Then during second period we finished up our lab and went over the summary questions with Mrs. Foglia.
Here are the highlights from today’s notes: (the Roman numeral is the slide name and the letters are some of the main points of the slide.

1. Correlations of species to food source:


1. Correlation between different species and food types


2. A lot of behavior is genetically controlled what you eat, etc.


3. Adaptive Radiation: when a species arises in a new area, it has the adaptation to live in a new niche because they have successful inheritance or successful traits


2. Darwin’s Finches:
   


1. The beak differences between the finches allowed them to survive in their specific environment and allowed them to pass on those successful traits to their offspring.


3. Correlation of species to food source:


1. Darwin had noticed that among the tortoises, the shape of the shell corresponds to different habitats


2. This shows that depending on the environment and the availability of food, or in this case where the food is, adaptations can occur throughout a species to help them survive in that environment, just like the finches.


4. Many islands locally show variation in tortoise morphology: which is the shape of the body and through this evidence Darwin questioned that this is the reason why there was splitting of one species into several


5. Artificial Selection:


1. In this selection, nature does not select who gets to reproduce, but humans do like in agriculture.


2. We saw in class some examples of artificial selection in plants how they all were from the same species or ancestor but were different


6. Selective Breeding


1. On the slide we see a breed of pigeons which went through artificial selection. All of these pigeons came from the same ancestor.


2. This is further evidence to the fact that parents pass on traits to their offspring


7. A reluctant revolutionary


1. Darwin returns to England in 1836 with his idea of evolution and natural selection


2. He wrote papers describing his journey and he had finished his draft of species formation in 1844


3. Wanted his wife to publish his essay when he dies


4. He was scared to tell the world of his ideas because his ideas went against he science of the time and he did not want to ruin his career


8. Wallace’s Letter to Darwin


1. Wallace wrote a letter to Darwin asking him to review the letter he had wrote about the same idea Darwin wrote about but was reluctant to publish


9. The time was ripe for the idea


1. They both agreed to publish the their essays simultaneously that way they both can get the credit for their founding


10. Essence of Darwin’s ideas


1. 5 characteristics


1. Variation: any group of organisms in a population must have differences


2. More offspring are born than can possibly survive


3. As a result of overpopulation struggle for existence or competition


4. Characteristics that benefit the species and allow them to survive and reproduce, will be passed on to the offspring and soon that characteristic will be common in the population, changing the average characteristics of the population and this is called adaptations


5. Over a period of time, new variation comes in population and these processes lead to the emergence of new species


11. Natural Selection


1. All of the five characteristics refer to natural selection


2. Variation, overpopulation, competition, and differential survival based on traits


3. Successful traits leads to adaptations adaptations must be genetic to pass on to offspring


12. LaMarckian vs. Darwinian view:
    
    
    


1. LaMarck believed that since giraffes were stretching their necks to reach the food, that acquired long neck got passed on to their offspring


1. Problem: traits are determined by genes and that how they are passed on. He did not involve genes, he said that it just got passed on without genes


2. Darwin believed that longer necked giraffes were surviving better and therefore getting to reproduce and pass on their traits to their offspring through genes


13. Effects of Selection:


1. Directional selection natural selection pushed the population to one extreme side of variations variations lead to one of the tail or the edge


2. Stabilizing selection natural selection pushes the population to the middle of the population.


3. Disruptive Selection over time each extreme gets selected, over time no one is really in the middle and this is the beginning of speciation


14. Natural selection


1. Selection happens on any trait that effects survival and reproduction


2. Predation selection, physiological selection(how bodies work), sexual selection(the traits that allow you to get a mate)

Well that’s what we learned today and please do forgive me if I left something out or if my outline did not help you. If you have any questions or comments please post it on the blog or just reach me at school, in the classroom and you can ask me there.

Navneet

• This site will give you a better definition and example of artificial selection


• This site will give you more details about the Galapagos tortoises


• History of Alfred Wallace


• The whole LaMarck and Darwin view of the Giraffes neck


• This video shows a Galapagos tortoise walking: