[WEEK10] Charles Darwin and the theory of evolution

Learning objective

 

Describe why Lamarckian evolution does not occur

Lamarck noted that evolution occurs by acquisition of aquired characteristic. He expected that the trait aquired during one’s life time would inherited to the offspring so the species evolute. However, acquired characteristic cannot be inherited

 

Describe the role Alfred Wallace played in development of evolutionary theory, and why Darwin sat on his ideas for so long

Wallace noted that the variation makes the individual differences to adapt well on the environment or not

 

Understand how the following underpinned Darwin’s arguments:

- Observations of the fossil record

By researching the fossil, he found that the previous, ancestorial organisms have different appearance as ours and more closet to the surface, it became much similar to nowadays organisms. He expected that organism might changes its phenotype as time goes by

 

- Observation of natural variation with populations

Natural variation makes the differences between individuals that have more adaptable characteristic or not

 

- Logical extension of Malthus’ determinations on population growth

As malthus noted that indivudals make more offspring that can survive, competiton happens for preventing the

 

- An appreciation of geological processes and geological time

By observing glacier movements, and experiencing earthquake, he realized the plate tectonic

- Observations on the finches on Galapagos island

He found out that difference in niches, diet of finches changes the species phenotype

 

Understand that individual organisms do not evolve, and understand what “descent with modification”, “survival of the fittest”, and “acquisition of acquired characteristics” mean.

descent with modification : While passing the gene to offspring, the crossing over/ mutation/ independent assortment … attribute to gene modification, but it is not evolution. Evolution doesn’t happen to individual. This modification of gene attribute to variation in population, and when the adaptable characteristic are reproduced more, it brings about evolution, gradual change.

 

survival of the fittest : The individual with most adaptable characteristic is able to survive and reproduce to pass the next generation its characteristic

 

acquisition of acquired characteristics: is not inherited. (Lamark)

 

 

Understand that evolution does not create change, it allows favourable characteristics that already exit in populations to increase in frequency in future generations.

 

 

 

Describe the three examples of natural selection discussed: Darwin’s observations of Galapagos finches, recent findings on beak depth in finches related to changes in climate, and the case of the Peppered Moth in England.

->Galapagos Finches: Depending on the niches (environment), food source changes the phenotype of the Galapagos finches’ beak.

 

->Recent founding proved that after severe drought (climate change), finches with larger and stronger beak would only survive due to the food source availability so the population of finches with large beak increases (because only them were survived)

 

->Peppered moth in England: as pollution became severe due to industrialization, pale colored moth became conspicuous to the surrounding, the population decreased by the increased probability to be noticed by predators. As the pollution normalized, the population imbalance between dark moth and pale moth came back to normal.

 

Ubderstand how artificial selection can accelerate differentiation of organisms.

 ->articial selection can act on appearance and behavioral differentiation

By reducing the generation aggressively

-chiwawa, a domestication of its size

-Behavioral difference between Wild bull and braham, violent bulls are all killed

-From the wild mustard, each part of the wild mustard is selected and extracted to grow them into different plants

Understand the conditions under which raw materials of life likely originated on Earth,

C, H, O, N, S makes up organic molecules such as carbohydrate, protein, lipids to form macromolecules. They are made up in high energy environment. when the earth’s early age, toxic volcanic activities made high energy concentrated environment.

 

Be able to give approximate dates on the age of the earth and when life first arose.

-> Earth is estimated to be generated ~4.5BYA. The first life is unicellular prokaryote, cyanobacteria in the thin layer of the rock, and it is estimated to be formed ~3.5BYA

 

Describe the purported role of vesicles in forming “proto-life”

->vesicle can spontaneously formed (catalysed by clay) Vesicles can produce more vesicles from themselves. Vesicles can include RNA which is called pro-to cell.

 

Present arguments used to support the contention that RNA evolved before DNA

->RNA can self replicate, ribosomal RNA is RNA that produce RNA RNA is a catalyst (riboenzymes), RNA could be a template to produce DNA strand (DNA is more stable and a source of genetic information), it is not difficult to transfer nucleotide sequences to daughter vesicles

 

Be able to describe the endosymbiont theory with respect to the evolution of eukaryotic cells and development of multicellular life

->the evidence of endosymbiont of mitochondria is that they have their own DNA, cell membrane, ribosome, and they are more similar to bacterial ribosome

 

Understand the importance of stromatolites to evolution of eukaryotes

->Stromatolites produce oxygen as a byproduct. After aerobic metabolism became enable for the organism, it is more efficient in ATP synthesis, it accelerate the eukaryotes evolution

 

Understand why unicellular organisms can be described as the most successful organisms on Earth

-> The single-celled organisms have basic requirements such as simple food and less complicated growth habitats. These properties make them highly adaptable to some level of changes in food and habitat.

 

Be able to describe the process of carbon dating, and limitations  of it

-> carbon dating is using the C12 to C14 ratio to define the years of the fossils. C12 is stable compared to C14 as they are trapped in bone or cell tissues. The amount of Radioactive C14 changes to N14 by beta decay over years. The half life of C14 is 5730 years. About 75,000 years so liitle carbon will be present that no longer carbon dating is possible.

 

Describe some of the causes and effects of mass extinctions, and the relevance of the Cretaceous extinction to the evolution of mammals

-> Mass extinction happens by the catastrophic disaster. Cretaceous extinction is the most recent mass extinction happended in ~65BYA. It extincted dinausours giving a chance to develop mammal lives

 

Present arguments to support the contention that we currently in a 6th mass extinction event

-> The decreasing rate of biodiversity is faster than any ages, eventhough there is no catastrophic disaster, human pollution and manipulation/colonnisation + man taking over natural resources and space, destroying habitats and introduction of non-natives species make the matter

PPT

 

Charles Darwin and Alfred Wallace

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ideas leading up to Evolution

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Linnaean Classification

phylony 계통 taxonomy 분류?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Lamarck

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Darwin's key points

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Examples of natural selection