II. Connections
1. Sympatric Speciation is a speciation model that occurs within the home range of an already existing species, or in other words without the presence of a physical barrier. This is caused by polyploidy, in which individuals inherit three or more sets of chromosomes of their species due to the failure of mircotubules to attach to chromosome kinetechores during mitosis or meiosis. With the extra chromosomes, the offspring are unable to mate with their parent species but can reproduce asexually or with another polyploid individual, resulting in the creation another species of organisms.
2. Endosymbiosis is a theory for the origin of organelles such as the mitochondria and chloroplasts that claims that heterotroph cells consumed autotroph cells due to their ability to engage in aerobic respiration, but since they nefused to digest them, the consumed cells remained and lived out their lives in the host cell. Each cell in this interaction is benefited, classifying it as a symbiotic relationship. The reason for heterotrophs preying on aerobic prokaryote cells was due to the alteration of atmospheric gases by the emergence of photosynthesis, for they introduced free oxygen, therefore allowing eukaryotic cells to evolve from prokaryotes.
3. Adaptive radiation is a type of speciation that is characterized by a burst of divergences from a single lineage that results in a entirely new species. This occurs either when a lineage uptakes a vacant adaptive zone (set of niches) or competes with other resident species well enough to force them adopt another niche. This latter incident refers to character displacement, which is a phenomenon in where a species will adopt a new niche if its original one conflicted with that of another species, relating to Gause's principle in that no two species can share the same niche.
4. Proto-cells comprise the transitional forms between simple organic compounds and the first living cells. They are self- replicating membrane-bound sacs that have systems of enzymes and other agents of metabolism. It is believed that their ability to self-replicate arose with the spontaneous assembly of RNA subunits due to an increase in temperature, and the formation of an enclosed membrane due to the moistening of protein chains.
III. Essentials
1. Prezygotic Mechanisms
-Mechanical Isolation: A species's body parts are not physically compatible to another species for the purpose of mating, or pollinating
-Temporal Isolation:When specific timing for reproduction differs between populations, those populations cannot interbreed
-Behavioral Isolation: Since certain species of organisms include courtship displays in their reproductive process, species that are not pre-wired to perform or recognize a particular courtship display will not be able to interbreed with a similarly related species that is pre-wired to do such.
-Gamete Morality: Gametes of different species are incompatible, so no fertilization occurs
Postzygotic Mechanisms
- Hybrid Inviability: Hybrid embryos die early or the new individuals die before they can reproduce
- Hybrid Sterilty: Hybrid individuals are unable to produce functional gametes
2. The gradual model of speciation, known as "gradualism", holds that speciation occurs as a result of slight morphological changes of individuals throughout a relatively long span of time. On the contrary the punctuated model of speciation, or “punctuated equilibrium”, claims that most morphological changes occur in a smaller, more brief geologic period, due to factors such as directional selection, genetic drift, the founder effect, and bottlenecks, for such accelerate the rate of speciation.
3. In the attempt the prove the hypothesis formed by chemical processes, Stanley Miller placed water, methane, hydrogen, and ammonia in a reaction chamber. Then he disrupted the mixture by circulating it and zapping it with sparks, to simulate lightning strikes. Amino acids and other small organic compounds were present in the chemical mixture a week later, therefore affirming the hypothesis.
4. A critical example that supports the endosymbiosis theory is the chance discovery of Jeon Kwang in 1966, in where his culture of amoebas was infected by rod-shaped bacteria cells, which caused some cells to die, while the the others, which were smaller, just grew more slowly. After 5 years of maintaining the infected culture, the infected amoebas were producing additional bacteria cells while thriving. When exposed to antibiotics, only the bacteria and non-infected cells perished, not the amoebas. Evidence then showed that infected cells became unable to manufacture a specific enzyme, so instead they depended on their invader bacterium to synthesize it, therefore exemplifying a endosymbiotic relationship.
5. The cladogram is on the cards we turn in for the chapters…
1. Sympatric Speciation is a speciation model that occurs within the home range of an already existing species, or in other words without the presence of a physical barrier. This is caused by polyploidy, in which individuals inherit three or more sets of chromosomes of their species due to the failure of mircotubules to attach to chromosome kinetechores during mitosis or meiosis. With the extra chromosomes, the offspring are unable to mate with their parent species but can reproduce asexually or with another polyploid individual, resulting in the creation another species of organisms.
2. Endosymbiosis is a theory for the origin of organelles such as the mitochondria and chloroplasts that claims that heterotroph cells consumed autotroph cells due to their ability to engage in aerobic respiration, but since they nefused to digest them, the consumed cells remained and lived out their lives in the host cell. Each cell in this interaction is benefited, classifying it as a symbiotic relationship. The reason for heterotrophs preying on aerobic prokaryote cells was due to the alteration of atmospheric gases by the emergence of photosynthesis, for they introduced free oxygen, therefore allowing eukaryotic cells to evolve from prokaryotes.
3. Adaptive radiation is a type of speciation that is characterized by a burst of divergences from a single lineage that results in a entirely new species. This occurs either when a lineage uptakes a vacant adaptive zone (set of niches) or competes with other resident species well enough to force them adopt another niche. This latter incident refers to character displacement, which is a phenomenon in where a species will adopt a new niche if its original one conflicted with that of another species, relating to Gause's principle in that no two species can share the same niche.
4. Proto-cells comprise the transitional forms between simple organic compounds and the first living cells. They are self- replicating membrane-bound sacs that have systems of enzymes and other agents of metabolism. It is believed that their ability to self-replicate arose with the spontaneous assembly of RNA subunits due to an increase in temperature, and the formation of an enclosed membrane due to the moistening of protein chains.
III. Essentials
1. Prezygotic Mechanisms
-Mechanical Isolation: A species's body parts are not physically compatible to another species for the purpose of mating, or pollinating
-Temporal Isolation:When specific timing for reproduction differs between populations, those populations cannot interbreed
-Behavioral Isolation: Since certain species of organisms include courtship displays in their reproductive process, species that are not pre-wired to perform or recognize a particular courtship display will not be able to interbreed with a similarly related species that is pre-wired to do such.
-Gamete Morality: Gametes of different species are incompatible, so no fertilization occurs
Postzygotic Mechanisms
- Hybrid Inviability: Hybrid embryos die early or the new individuals die before they can reproduce
- Hybrid Sterilty: Hybrid individuals are unable to produce functional gametes
2. The gradual model of speciation, known as "gradualism", holds that speciation occurs as a result of slight morphological changes of individuals throughout a relatively long span of time. On the contrary the punctuated model of speciation, or “punctuated equilibrium”, claims that most morphological changes occur in a smaller, more brief geologic period, due to factors such as directional selection, genetic drift, the founder effect, and bottlenecks, for such accelerate the rate of speciation.
3. In the attempt the prove the hypothesis formed by chemical processes, Stanley Miller placed water, methane, hydrogen, and ammonia in a reaction chamber. Then he disrupted the mixture by circulating it and zapping it with sparks, to simulate lightning strikes. Amino acids and other small organic compounds were present in the chemical mixture a week later, therefore affirming the hypothesis.
4. A critical example that supports the endosymbiosis theory is the chance discovery of Jeon Kwang in 1966, in where his culture of amoebas was infected by rod-shaped bacteria cells, which caused some cells to die, while the the others, which were smaller, just grew more slowly. After 5 years of maintaining the infected culture, the infected amoebas were producing additional bacteria cells while thriving. When exposed to antibiotics, only the bacteria and non-infected cells perished, not the amoebas. Evidence then showed that infected cells became unable to manufacture a specific enzyme, so instead they depended on their invader bacterium to synthesize it, therefore exemplifying a endosymbiotic relationship.
5. The cladogram is on the cards we turn in for the chapters…
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