Chp 25 Flashcards
4 conditions that makes origin of life possible
The abiotic synthesis of small organic molecules, The joining of these small molecules into macromolecules, The packaging of these molecules into protocells, The origin self-replicating molecules that eventually made inheritance possible
Describe the Miller Urey experiment
- The main purpose of the experiment was to see if life could actually develop in the early earth’s atmosphere by creating an early earth like environment to see if life would appear. In order to do this they put molecules that were thought to exist in early Earth’s atmosphere into a closed machine. In the machine there were Methane, hydrogen, and ammonia gases. To lightning discharges, Miller also used the electrical current to represent the lighting. The result was that amino acids were created and later other organic molecules were also created by putting different molecules into the system but however no life was formed.
Explain the evidence for protocells
- Experiments showed that vesicles can exhibit certain properties of life, like simple reproduction and metabolism, as well as the maintenance an internal chemical environment different from that surroundings. For example, vesicles can form spontaneously when organic molecules are added to water. When this occur the hydrophobic molecules add montmorillonite, that increases the rate of vesicle self assembly. The clay also increases the likelihood that the molecules will react with each other and vesicles. Abiotically produced vesicles can “re- form produce” on their own (Figure 25.3b), and they can in sie of their contents. increase without dilution also absorb particles, including those on montmorillonite which RNA molecules have become attached and other organic
- Describe the evidence scientists use that suggests that RNA was the first genetic material. Explain the significance of the discovery of ribozymes 6pts
RNA plays a central role in protein catalytic functions Ribozyme helps to carry out catalytic functions and can make complementary strands of short pieces of RNA. RNA molecules with certain base sequences are more stable and replicate faster and with fewer errors The RNA molecule whose sequence is best suited to the surrounding environment and has the greatest ability to replicate itself will leave the most descendant molecules RNA molecules that carries genetic information were able to replicate and store information about the vesicles that carried them. Vesicle could grow, split, and pass its RNA molecules to its daughters and the daughters would have some of properties of their parent.
Describe how natural selection may have favored the proliferation of stable protobionts with self-replicating, catalytic RNA 4pts
Because if the Vesicle could grow, split, and pass its RNA molecules to its daughters and then the daughters would have some of properties of their parent ant this could help them have a greater chance of survival and being able to pass its abilities to its offspring.
Explain how scientist date fossils.
Common techniques that scientists used is radiometric dating, which is based on the decay of radioactive isotopes. In this process, a radioactive “parent” isotope decays to a “daughter” isotope at a fixed in rate. The rate of decay is expressed by the half-life, which is the time required for 50% of the parent isotope to decay. By measuring it in a fossil, we can determine the fossil’s age but however it could only work up to 75,000 years.
3 eons and 3 eras
Archaean, Proterozoic, and Phanerozoic eon
Paleozoic Mesozoic, and Cenozoic era.
Explain how scientists think okygen became part of the atmosphere
When oxygenic photosynthesis first evolved, the free o2 it produced dissolved in the surrounding water until it reached a concentration that will react with dissolved iron and this result in iron oxide. When the seas and lakes become saturated with O2 it begins to “gas out” of the water and enter the atmosphere.
What is the endosymbiotic theory? what benefit would each part experience? Give two pieces of evidence scientists use to show the connection between mitochondria and plastids.
endosymbiont theory- stated that mitochondria and plastids are small prokaryotes that began living within larger cells. The ancestors of mitochondria and plastids probably gained entry to the host cell as undigested prey or internal parasites. It could become mutually beneficial because a host that is heterotroph could use nutrients released from photosynthetic endosymbionts and because it is in a world that was becoming increasingly aerobic, it could benefit from the endosymbionts that turned the oxygen to advantage.
Evidence: The inner membranes of both organelles have enzymes and transport systems that are similar to those found in the plasma membranes of living prokaryotes. Mitochondria and plastids replicated by the splitting process are similar to certain prokaryotes. They also have dna and cellular machines.
Cambrian explosion
- a period where there started to be claws and other features for capturing preys and new defensive adaptations.
Describe the three major types of tectonic plate movement and given an example for each
Divergent boundary- occurs when two tectonic plates move away from each other. Example: the North American and Eurasian plates are drifting 2 cm apart from each other each year. Convergent boundary- when an oceanic plate collides with a terrestrial plate the oceanic plate usually sinks below the terrestrial plate and when the oceanic plates or two terrestrial planets collide with each other, violent upheavals occurs and forms mountains. Example: when the Indian plate crashed into the Eurasian plate and forms the Himalayan mountains. Transform plate boundary- when two plates sliding past each other forms some regions of earthquakes. Example: Califomia’s San Andreas is part the border when two plates slides.
Give an example of how scientists think continental drift supports diversification
it could alter the habitats that organism will live in which will cause new adaptation in order to survive.
Causes climate shift will cause organisms to adapt. Example the southern tip move from tropics to 40 degree which causes organisms to adapt.
- Distinguish between the Permian and Cretaceous mass extinctions
Permian mass extinction occurred at the time of volcanic eruptions. Geologic data indicate that an area of 1.6 million km2 was covered with a layer of lava hundreds to thousands of meters thick. It also warmed the global climate by an estimated 60C. The Cretaceous mass extinction occurred about 65.5 million years ago, marks the boundary between the Mesozoic and Cenozoic eras and extinguished more than half of marine species and eliminated many families of terrestrial plants and animals, including all dinosaurs.
- Give an example scientists use to support adaptive radiations
Fossil evidence indicated that mammals underwent a dramatic adaptive radiation after the extinction of terrestrial dinosaurs Because of the the disappearance of dinosaurs, mammals expanded in both diversity the and size, filling in the ecological roles of terrestrial dinosaurs.
- Explain the experiment regarding the genes and legs of drosophila
researchers cloned the Ubx gene from Drosophila and Artemia then they genetically engineered fruit fly embryos to express either the Drosophila Ubx gene or the Artemia Ubx gene throughout their bodies, The drosophila gene expressed one hundred of the limbs in the embryos and the Artemia gene expressed only 15 percent.
- Explain gene regulation through the example of the threespine stickleback fish
The three spine stickleback fishes used to have spines but now in the lakes the spines are often reduced or absent in stickleback fish and this happened because there is a change in gene expression of Pitx1.
- What is binomial nomenclature?
The first part of the name is genius and the first letter is capitalized and the second part is species and it is italicized.
Taxonomy of life
Species, genus, family, order, class, phylum, kingdom, and domain (Bacteria, Eukarya, and Archaea).
Explain a phylogeny tree and define common terms associated with it 7pts
Phylogenetic tree- an evolutionary history of a group of representing in organisms branching diagram. Branch point is where lineages diverge The point at the ancestral lineage represent the common ancestor When a line branches out to three it forms a polytomy: an unresolved pattern of divergence
