Evidence of Evolution

 

Darwin observed the Galapagos finches had a grade series of beak sizes and shapes and predicted these species were modified from one original mainland species. Darwin called the differences offspring with inherited characteristics that allow them to best compete natural selection. Darwin believed that the different beak shapes were adapted over time to equip species with beaks that allow them to acquire different food sources.  

“During 1977, a drought period altered vegetation on the island. After this period, the number of seeds declined dramatically; the decline in small, soft seeds was greater than the decline in large, hard seeds. The large-billed birds were able to survive better than the small-billed birds the following year.”

Source: Boundless. “The Galapagos Finches and Natural Selection.” Boundless Biology. Boundless, 20 May. 2016. Retrieved 24 May. 2016 from https://www.boundless.com/biology/textbooks/boundless-biology-textbook/evolution-and-the-origin-of-species-18/understanding-evolution-124/the-galapagos-finches-and-natural-selection-496-13095/

 

Male songbirds have developed different colored feather patterns and songs to attract a mate. The birds with the brightest feathers or prettiest songs, for example, may sexually outcompete other males. The male birds are able to find a female partner and pass their genes on to their offspring. Sexual selection is specifically due to female choice and male competition for mates.

This study shows that that there is a significant correlation between male bird’s tail length and the number of successful offspring. The top scatter plot shows that birds with a longer tail have more active nests. The bottom plot shows that Males with longer tails produce offspring quicker. 

http://sciencecases.lib.buffalo.edu/cs/files/widowbirds.pdf

 

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A mutation is a change in DNA usually caused when a cell splits. When the cells fail to make an exact copy, that is a mutation. Some mutations are due to environmental factors like UV radiation, or certain chemicals and are called Somatic Mutations. Most Somatic Mutations lead to certain disadvantages or diseases. https://www.youtube.com/watch?v=K4FeRP6LdoA.

https://www.sciencenews.org/blog/wild-things/some-birds-adapt-chernobyl%E2%80%99s-radiation.

After the nuclear disaster in Chernobyl, scientists have discovered that birds living around the area of the nuclear site have developed smaller brains and eye cataracts. On the positive side, scientists have discovered that birds living in high radiated zones have more antioxidants. It seems as though some species of birds are adapting to the high levels of radiation.

“To our knowledge, this represents the first evidence of adaptation to ionizing radiation in wild populations of animals,” the researchers write.

 

Genetic drift occurs when random factors impact the frequency of alleles in subsequent generations of a population. Because it is random, smaller populations are more susceptable to the effects of genetic drift.

https://www.youtube.com/watch?v=dik24hBhmcw.

A bird may have an allele for two different beak sizes. Depending on which alleles show up in the offspring, genetic drift could cause one of the beak sizes to disappear from the population thus reducing the genetic variation of the birds gene pool. http://www.softschools.com/examples/science/genetic_drift_examples/123/.

A study on the levels of genetic variation of mainland and island bird populations was conducted. A significant majority of island populations have less genetic variation than the mainland populations. The average reduction of genetic variation was 29%. Genetic factors play a key role in the extinction of a specific type of species in smaller populations.

 

Gene flow is the movement of alleles from one population to another. If the trait of one population is introduced to a population without that trait, and the trait happens to be an advantage for that species, the frequency of that traits allele is going to rise.

https://www.youtube.com/watch?v=ALS7UO6F1Zs.

A study one the Zosterops borbonicus suggests that due to behavioral processes, the bird shows very low levels of gene flow. 11 populations of the species was analyzed to detect gene variation. They found that even though the birds didn’t have much geographical separation, the birds populations still had large amounts of genetic variation. They believe this is due to the birds unlikeliness to disperse into other surrounding areas. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3907105/.

AP Bio Cell signalling summative reflection.

Pheromone mating pathway

Pheramone matA (ligand) finds the receptor
GPA1 is activated and changes GTP into GDP
GDP activates protein kinase
Protein kinase then phosphorylates FUS3
FUS3 activates STE 5 a scaffled protein  which then transcribed the Pheramone mating response gene.

The Pheromone mating response gene was difficult to model because there are so many signals and pathways. However, we were able to simplify this process. We formed a cell shape to help show the pathways of the hormones like GDP and protein kinase. I think if we were to help the class fully understand this process we would need more time and a detailed model with pictures. Considering our resources, I believe we did well in explaining the Pheramone pathways.

Video

url

https://drive.google.com/folderview?id=0B5Sihv4gNfm_SHJRaW92ck5oblk&usp=sharing

DNA replication

Helicase unzips the strands of DNA while

Helicase unzips the DNA strand while Topoismerase snips to relieve the tension.

RNA attaches to the DNA

RNA attaches to the DNA strands

RNA polymerase primer attaches to the DNA

DNA Polymerase attaches to each stand going in opposite directions

The DNA strands are split

DNA polymerase replaces the RNA

Ligase then connects the strands of DNA

Humans and Apes

Humans evolved from a common ancestor millions of years ago. Species migrated to different environments and devolved special traits that were best suited for the environment through genetic mutation. In the article is states “ That ancestor lived in environments that ranged from thick forests to open grasslands.” Meaning that because of the different habitats, the species developed different characteristics and eventually into different species.  The apes that had stronger shoulders and tails would do better in trees while the species with short shoulders and no tail adapted best to fields. Eventually different species were created and were so different genetically that they could no longer interbreed. I chose this topic because I wanted to know how humans and apes evolved from a common ancestor. This is an example of a prezygotic reproductive barrier and sympatric speciation known as Ecological Isolation. The populations were not separated by physical barriers like a canyon or river but by ecological isolation, breeding in different habitats.

Claim: Humans and Chimps evolved through Ecological Isolation from the same common ancestor.

Evidence:”That Monkey-like ancestor lived in environments that ranged from thick forests to open grasslands.” stated in the article Evolution from The Tech website. Mutations that benefit a species through natural selection continue to be passed down to other species. “the development of different species (speciation) is driven by changes (mutations) in DNA.” and “every so often a mutation comes along that is actually helpful, and these mutations can really drive speciation.” EX: A Polar Bear is more fit for the Arctic than Camel. In the case between Humans and Apes,  the mutation that made the animal most fit for its environment continued to pass it genes to the next generation.

Reasoning: The “Monkey-like ancestor” developed into Humans which developed long legs and lost their tails as they adapted to grasslands and Apes developed long arms and a stronger upper body to allow them to move through the trees easily.

Source: http://genetics.thetech.org/ask-a-geneticist/human-monkey-evolution-speciation. 

Moth Mutation

In the case of a moth, a moth with a black wing allele would blend better in an environment with darker trees than a white winged moth. Moths with the dark wing mutation would began to appear more frequently in the environment because they have better fitness. The moths with the phenotype of dark wings are favored by natural selection.

Do Meal Worms Prefer Wet or Dry Food

Question: Do meal worms prefer wet or dry food?

Hypothesis: Meal worms have no preference when it comes to their food being dry or wet.

Materials:

• Dish
• 10 meal worms
• 6 dry cheerios
• 6 wet cheerios\
• stop watch
• data table

Procedure:

• Place 6 of the 12 cheerios in a dish of water and let soak for 5 min
• place 6 dry and 6 wet into the feeding dish before placing worms in dish
• every 1 minute for 5 minutes record the number of worms feeding on either the wet, or dry food or not eating.

• Data Table and observation
• 
• 

• 

Conclusion: Almost immediately, 7 of the 10 worms fed on the wet food and in the end, never once did any of the worms feed on the dry cereal. We believe this is because meal worms naturally feed on decaying plants and insects which we are assuming are moist due to the soil and decaying process. The end results were 9 feeding on the wet food, 0 on the dry food and 1 not eating. We observed that the worm not eating was dying either from when we had gathered him or by accident injury from his previous attempt to escape.

Science 6 word memoir post

Science is the answer to everything.

Last Blog of My Junior Year.

“I know that luck has a way of happening to people who shoot high, who never sell themselves short.”

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