Week 3 Learning

This week in biology we continued to learn about evolution mostly through lectures, and worksheets.

LECTURE: EVIDENCE FOR EVOLUTION

  • Falsifiability
    • Scientific thoughts can never be proven
  • Hypothesis
    • A testable statement about the universe
  • Theories
    • A major unifying framework supported by all evidence currently known
  • Laws
    • A deduced fact that will always hold true if given certain conditions

FOSSIL RECORDS

  • Isotopes are used to figure out how old an organism is based on the half life of the isotope.
  • Transitional Fossils
    • Show evolutionary links between groups of organisms
  • Homologous Record
    • Similar characteristics resulting in common ancestry
  • Analogous Record
    • Similarities in adaptations resulting from similar evolutionary pressures.
  • Vestigial Organs
    • Structures that serve little to no function

Image result for homologous vs analogous structures examples

LECTURE: MOLECULAR RECORD

  • Genetic Code
    • Universal code used by ribosomes
  • Building family trees
    • Closely related species are the same line of descent until their divergence from a common ancestor, this creates genetic differences
    • Fewer differences=more recently diverged
  • Genome sequences
    • All our genomes are sequenced
    •  23 chromosomes
  • Selection
    • Artificial
      • Selective breeding
      • Uses variations in the breed
  • Biogeography
    • Original evidence that informed Darwin
    • Organisms close to each other are found in similar areas

PHYLOGENIC TREES

  • Trace the path of evolution. Each “branch” of the tree is the development of a separate species.

Image result for Phylogenetic trees

QUESTIONS/COMMENTS

  • At what point is selective breeding illegal?

LINKS

Week 2 Learning

This week in AP Biology we learned more about evolution, the common ancestry of life, and hypothesis on  molecular origins of life.

Evolution

Chapter 9 taught us about evolution, variation, and natural selection. We also learned about different evolution theories besides natural selection such as how individuals do not evolve, populations do. We touched on convergent evolution, which is a similar problem, similar solution.

See the source image

It makes me wonder if a single population can solve a “problem” with multiple different adaptations? We dug deeper into Darwin’s life, and learned how he came from a wealthy family and went on a voyage around the world and studied different organisms. Through the Galapagos Island, Darwin discovered natural selection. However, he didn’t publish this theory for twenty years because Alfred Russel Wallace sent a paper to him with the same theory for Darwin to review. Darwin quickly published his theory before Wallace could get credit first. He also wrote The Origin of Species.

Common Ancestry of Life

Finally, the lecture taught us that there was a common ancestry of life. This was very interesting to me and hard to wrap my head around. We all come from 1 ancestor, kind of like a family tree. This makes me question how scientist came to this conclusion and what exactly that common ancestor is and where it came from. Did it come from a bacteria?

See the source image

Hypothesis on Molecular Origins of Life

First there is the Metabolism-First Hypothesis. This consists of several different hypothesis proposed by different researchers about how life first formed. These hypotheses are united by the idea that ordered chemical reactions was the property of the initial life form. Then, there is the Replication First Hypothesis. This is the belief that the first life was a self replicating DNA. This makes me wonder how RNA could replicate and store.

Everything we have learned this week is connected to Big Idea 1, talking about common ancestry, the hypotheses for the origin of life, and the continuation of evolution.

Links:

Click to access 6c66960a43bf98d9d9f862f57a84132dd640.pdf

 

Week 1 Learning

This week in AP Biology we began by refreshing our memory on basic statistics such as calculating the standard deviation and standard error of mean. We also covered evolution and learned about how this occurs in real life, as well as natural selection and key people who paved these ideas.

Descriptive statistics helps me describe basic features in given data, and how to summarize data. The standard deviation is a measure of the variation within data, and we learned how to calculate this. We also learned how to calculate the statistical mean, which is the average that is used to derive the central tendency of the data in a question. We used these ways of calculation on data from the Galapagos finches to practice the formulas. This was helpful in order to refresh my memory on statistics which I took last year, and also how it relates to biology.

The definition of evolution is descent without modification. It is the study of how organisms change over time. Scientists who helped develop ideas such as life evolving, inheriting traits, and carrying capasities include Thomas Malthus, Charles Lyell, Jean Baptiste Lamarck, and Alfred Russel Wallace. It wasn’t until Charles Darwin, however, that natural selection was discovered. Charles Darwin was a scientist who led this new idea of evolution through his work with the Galapagos finches. He published The Origin of Species which explains the changes of beaks of finches over time through natural selection. Because of a drought on one of the islands, the tiny seeds disappeared and so birds with small beaks died off for they couldn’t eat the big seeds. Thus, more birds began to have larger beaks. When the fit animal survives, it reproduces and passes on its traits to its offspring.

Image result for charles darwinImage result for galapagos finches beaks before and after drought

The Rock Pocket Mice video was a good example for me to understand natural selection. I learned how mice evolved in oder to survive their respective climates. When the lighter mice lived on the darker rock, they were easily seen by predators and died off. Then the few mice that mutated to have darker fur survived more because they were able to blend in with their surroundings. They survived, and reproduced more darker mice.

In conclusion, this week I learned about evolution, natural selection, and statistics. I used this knowledge on examples such as Galapagos finches and Rock Pocket mice. I learned how this connects to Big Idea 1, that the process of evolution drives the diversity and the unity of life. Without natural selections, many species wouldn’t be alive today. Next week I hope to dive deeper into speciation and how a new species form.

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