Flashcards in Chp 25 Deck (48):
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
2. 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
3. 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
4. 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.
- 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.
13. 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.
14. 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.
15. 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.
16. 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.
1. 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
Give the three things according to scientists that can/cannot be learned from phylogenetic trees 6pts
Phenotypic similarities The actual ages of particular species How much change had occurred in each lineage
Distinguish between homologous and analogy using wings
The underlying skeletal of bats is homologous to birds but because their wings are not similar because flight is enable in different ways and they are from different ancestors they are analogous because how they function differently. It is only homologous when they are function similar and are from the same ancestor.
Molecular systematics and difficulties
the discipline that uses data from DNA and other molecules determine evolutionary relationships. There will be out groups and first they have to put the homologous together.
Define clades, monophyletic, paraphyletic, and polyphyletic.
clades- each includes an ancestral species and all its descendants. Normally are with in larger clades
monophyletic- consists of an ancestral species and all of its descendants
paraphyletic consists of an ancestral species and some, but not all, of its descendants.
polyphyletic- includes taxa with different ancestors.
Contrast shared ancestral character with shared derived character
Shared ancestral character- a character that originated in an ancestor of the taxon Shared derived character- a character shared by all mammals but not found in their ancestors
Describe how maximum parsimony and maximum likelihood are used in constructing a phylogenetic trees
According to the principle of maximum parsimony, we should first investigate the simplest explanation that is consistent with the facts and always work because of this we with the simplest the first.
The principle of maximum likelihood states that given rtain probability rules about how DNA sequences change over time, a tree can be found that reflects the most likely sequence of evolutionary events and we use this to determine which tree likely true. is
Similarity between birds and dinosaurs
Both lay eggs, build nests. And sit on their eggs.
Orthologous genes and paralogous genes
orthologous genes those found in different species, and their vergence back to traces the speciation events that produced the species.
Paralogous genes the homology results from gene duplication
Because if the duplication that causes multiple copies of genes to diverged from one species over time it slowly evolved and now each have different functions but yet still one family because they emerged from the same species.
Concept of molecular clock
orthologous genes those found in different species, and their vergence back to traces the speciation events that produced the species. Paralogous genes the homology results from gene duplication: uni Because if the duplication that causes multiple copies of genes to diverged from one species over time it slowly evolved and now each have different functions but yet still one family because they emerged from the same species.
Rate may vary on different genes.
Problems of molecular clock
natural selection could cause some DNA changes to be favored. Because the estimation assume that the clock had been constant for a billion years or more the estimates are highly uncertain.
Sequence events from two kingdom to current kingdom
Early taxonomists classified all species into two kingdoms which are plants and animals. Because bacteria had a cell wall, taxonomists placed them in and the plant kingdom Eukaryotic unicellular organisms and Fungi are also consider reason for this plants. The is because they are not able to move and they consider things that were able to move as animals. In the late 1960s, more biologists start recognize five kingdoms: Monera (prokaryotes), Protista (a diverse kingdom consisting mostly of unicellular organisms), Plantae, Fungi, and Animalia. This new system set prokaryotes apart from all eukaryotes by placing them in different kingdom. People start to realize a problem because some prokaryotes differ as much from each other as they do from eukaryotes. These difficulties have led biologists to adopt a three-domain system. Which includes three domains: Bacteria, Archaea, and Eukarya and are a level higher than the kingdom level.
Ring of life
Researchers hypothesized that because eukaryotes arose as a fusion so it must have a close evolutionary relationship and they are all connected so it can not the be depicted in tree of life but in a ring of life because they are all connected.
Salt to preserve food
It could be use to preserve food because salt dehydrates the food by absorbing and by doing this it makes the environment too dry to support bacteria or molds.
Gram positive and negative
Grain positive- have simpler walls with large amount of peptidoglycan and this could help it stain better. Grain negative- have less peptidoglycan and are structurally more complex with an outer membrane that contains lipopolysaccharides. This can get rid of the stain by itself
Capsule, Fimbriae, sex pilus, nucleoid,plasmid, and endopores
capsule enables prokaryotes to adhere to their substrate or to others in the colony. Some also protects against dehydration and attacks from their host's immune system. Fimbriae helps to stick to their substrate. Sex Pilus- pulls two cells together to transfer DNA. Nucleoid- where their chromosomes are located Plasmid- small rings of independently replicating DNA molecules. Endospores- resistant cells that are able dormant for very long time and able to rehydrate when environments allow to do so.
Origin of flagella
scientist thought that it originated as simpler structure and were modified overtime. They think that flagellum evolved as other proteins were added to the system.
3 limits to the size of bacterial colonies
the amount of nutrient supply, poison with metabolic wastes, and competition from other microorganisms.
How prokaryotic genome differ from eukaryotic genome
prokaryotic genome is in a circular shape but eukaryotic genome is in the form of a double helix.
Briefly explain how rapid reproduction, mutation, and genetic recombination lead to high levels of diversity in prokaryotes 6pts
Rapid reproduction- because it reproduces so quickly so error occurs more often and therefore causes more diversity in prokaryotes. Mutation- can lead to differences between prokaryotes. Genetic recombination- could help the prokaryotes to get new Dna formation and therefore be more diverse from others.
How transformation works
In transformation, the genotype and phenotype of a prokaryotic cell are altered by the foreign DNA and the cell is now a recombinant many bacteria have cell surface proteins that recognize DNA from closely related species and transport it into the cell, inside the cell, the foreign DNA can be incorporated genome by homologous DNA exchange
In an Hfr cell, the F actor is integrated into the bacterial chromosome. Since an Hfr has a of the F- factor genes, it can form a mating bridge with an F-cell and transfer DNA. A single strand of F to factor breaks and begins move through the bridge. DNA the replication occurs in both donor and recipient cells, resulting in double-stranded DNA. The mating bridge usually breaks before the entire chromosome istransferred, DNA recombination can result in the exchange of homologous genes between transferred DNA and the recipient's chromosome. Cellular enzymes degrade any linear DNA notincorporated into the chromosome. The recipient cell, with new of genes but no F factor, is now a recombinant F- cell.
Outline the steps of transduction
A phage infects bacterial cell that carries the At and B+ alleles on its chromosome. This bacterium will be the "donor" cell The phage DNA is replicated, and the cell makes many copies of the proteins encoded by its genes. Certain phage proteins halt the synthesis of proteins encoded by the host cell's DNA may be fragmented. As new phage particles assemble, a fragment of bacterial DNA carrying the A+ allele happens to be packaged in a phage capsid. The phage carrying the A+ allele from the donor cell infects a recipient cell with alleles A- and B-. Recombination between donor DNA and recipient DNA occurs. The genotype of the resulting recombinant cell (AtB) ffers from the genotypes of both the donor (At B+) and the recipient (A- B-)
Outline the steps of conjugation and recombination in E. coli
A cell carrying an F plasmid forms a mating bridge with F- cell. One strand of the plasmid DNA breaks. Using the broken strand as the template, the cell synthesizes a new strand. Meanwhile, the broken strand peels off and one end enters the F- cell. The synthesis of the complementary strand begins. DNA replication continues in both the donor and the recipient cells, as the transferred plasmid strand moves farther into the recipient cell. Once DNA transfer and synthesis are completed. the plasmid in the recipient cell circularizes Now both cells are F+ cells
Explain the importance of nitrogen fixation
it converts N2 to NH3. It could increase the nitrogen available to plants. Plays a important part on maintains the nitrogen cycle ofecosystems.
Significance of biofilm
cells in a biofilm secrete signaling molecules causing colonies to grow channels in the biofilm allow nutrients to reach cells in the interior and allow wastes to be expelled.
3 major type of Archea
13 Extreme halophiles live in highly saline environments. Extreme thermophiles live in very hot environments. Methanogens releases methane as a byproduct of their way ofobtains energy.
Name, describe, and give an example of 3 major type of bacteria
Chlamydias can only survive within animal cells to depend on ATP as resources. Chlamydia trachomatis, is the most common cause of blindness in the world and causes nongonococcal urethritis. Spirochetes- spiral through their environment by rotating, internal, flagellum-like filament. Example: Treponema pallidum. cyanobacteria only prokaryotes with plant like oxygen-generating photosynthesis. Some have cells specialized for nitrogen fixation. For instance: oscillatoria.
Contribution of bacteria to the environment
Bacteria harvest chemical energy from H2s that is released from the vent and this could help many eukaryotic species. Sometimes where it forms a relationship with a larger organism and does not do any harm.
Mutualism, commensalism, parasitism
mutualism is an ecological interaction which both species would benefit from each other Example: the glowing oval on the eye of fishlike fish helps to attract preys and the bacteria reverie nutrients from the fish. Commensalism is when one side benefits while the other side is not harmed. Example: bacteria live on our skin but does not harm us and we provides them food like oils from our pores and a place to live. Parasitism is when parasite eats the cell's content, tissues, or body fluids of its host and parasites could cause diseases. Example: lice or flies.