Week 2- the origin of life/ evolution Flashcards
What did the miller urey experiment prove
It was the first attempt at stimulating ancient earth conditions, proving that it is possible life formed from chemical evolution
Biological evolution
change in things that reproduce, the change we see in biological evolution is not random, and is often adaptive —populations become better able to survive and reproduce within their environments, when conditions are right, it can even lead to new traits
3 parts of biological evolution
reproduction, (random) variation, selection
how do chemicals evolve
repetitive production, variation, selection
- The gradual development of chemical reactions that led to the formation of life
chemical evolution can produce new characteristics without relying on ___________
reproduction
Entropy
a state associated with disorder
How does entropy make sense as a beginning of life explanation
an energy source can drive matter in a feedback loop, which can find a shape that is well adapted to absorb the energy source
Where does life come from
- Early earth’s atmosphere was much different than ours
- Multi-cell organisms evolved from single cell organisms, which evolved from primative cells
- Nucleic acids assembled to store information
- Lipids organized to form “bags” which held water soluble molecules
Complex cell
Eukaryotic cell, us! little pockets (organelles)
Prokaryotic cell
Simple cell such as bacteria
Very primative cell
Needs
1. an enclosure (lipid/fat membrane)
2. Information inside
How did the first DNA building blocks form
(urey miller)
- Early earth had RNA, which is made of Nucleotides, which can arise spontaneously
- if it can replicate, it is a means for evolution
How did the outside of the first cell form
Lipid bags formed because lipid heads are hydrophilic and the tails are hydrophobic leading to the vesicle or bag
How did the first cell form
- RNA could replicate itself
- Lipid bags
- RNA replicates faster when contained
- Natural selection from different sequences
- THe RNA in a vesticle (primitive cell) is more likely to be replicated will increase in population
basic overview of our origin story
Other beginning of life hypothesis
- Thermal vents
- Some comets and meteorites could have produced organic chemicals
- Entropy
What explains the role of RNA in the origin of life
RNA can act as both genetic material and a catalyst for chemical reactions, making it a precursor to the first living organisms
Why does the human body have random features such as unstable knees and bad eyesight
they are a result of random genetic mutations that have been inherited over time
What is the significance of the presence of pseudogenes in the human genome
Then are the remnants of ancient viruses that have integrated into the human genome, providing evidence of common ancestry with other organisms
What are chills?
piloerection, each hair has a muscle. we used to be covered in hair and it was a negative feedback response to being cold
What is a vestigial structure
ancient characteristics that arent useful anymore, they demonstrate the evolutionary divergence of a species from their past form
Our classification
The __________ model is the most widely accepted hypothesis for the evolution of modern humans
replacement
Human races are not ___________ but __________ conception
biological - cultural
Genotype
Allels or varients a specific individual carries in a particular gene
GWAS
Genome wide association study: the discovery of associations between certain variations in our genetic code and certain physical traits
Single nucleotide polymorphism
a letter switch in the base
Indel
a base is missing or added
Skin color is a adaptation of
Homeostasis, the right amount of vitamin D and folate get into the skin
Eugenic
point to the existence of generic influence to deny the possibility of intervening to improve peoples lives
Genome blind
ignore genome difference
Anti-eugenic
use genetic data to accelerate the search for effective solutions
Survival of the fittest?
Reproduction of the fittest
- who has the variation that adapts them to their environment, allowing them to make it long enough to reproduce
VIST
Variation- all life forms vary genetically within a population
Inheritance- genetic traits are inhereted from parents and are passed on to offspring
Selection- organisms with traits that are favorable to their survival in the environment live longer and pass on traits
Time- evolution takes generations
What properties of the early earths environment supported the origin of life
Water, organic compounds (hydrogen, nitrogen sulfer), energy sources
What is the biochemical evidence of evolution
gradual development of inorganic chemicals into polymers in chemical evolution and eventually into a cell with DNA/RNA during biological evolution
How are humans classified
What are the major differences between modern apes and humans
- bipedal (evidence of this comes from the input site of the spine in the skull)
- Encephalization- increase in cranial capacity and mass
- Orthognathism- humans developed a less protruding jaw and flatter face. There was not a much of a need for strong jaw muscles and canines, which allowed for the restructuring of the face.
what characteristic evolved first
Bipedalism is thought to have evolved first
- Multiple theories, but the most likely one is that they needed to see over tall grass after relocating to the sahara due to climate shifts
What data do scientists use to build an evolutionary tree?
Scientists use GWAS- which is the discovery of associations between certain variations (SNP or indel) in our genetic code and a certain physical trait
SNP: position in the sequence where the letters do not match
Indel: addition or removal of a pair of DNA bases
What does branching on the tree represent?
- Branch point represents the most recent common ancestor of all species on those branches
- Node is the most recent common ancestor from all the organisms in the tree
- Root is the single branch point from where all branches originate
How do you read a tree to determine who evolved from whom?
- ORDER DOES NOT MATTER
- Relationships are conveyed by how the branches are connected to one another (distance is more important) → visually measure length of lines
What do we know about other members of the genus Homo, besides H. sapiens?
What is the definition of evolution?
under the right circumstances, simple creatures can give rise to more complex creatures
How do we determine evolutionary fitness?
Evolutionary fitness is determined by how well adapted an animal is to their surroundings. Fitness refers to the animals ability to survive and produce offspring
