Answer:
los mecanismos capaces de generar diversidad actúan para incrementar la variabilidad genética en la población que sufrió el cuello de botella
Explanation:
Un cuello de botella se refiere a una reducción drástica en el tamaño de una población (por ejemplo, debido a una catástrofe natural). Un cuello de botella es un fenómeno que está asociado a la reducción en la variación genética y fijación de ciertos alelos en la población resultante, lo cual es causado por la deriva genética, es decir, debido al muestreo al azar de los individuos que formarán la población en la siguiente generación. Paulatinamente, los mecanismos capaces de generar variabilidad genética aumentarán nuevamente la diversidad de la población que sufrió el cuello de botella. En una población de reproducción sexual, la variación genética se genera mediante cuatro procesos diferentes: 1-mutación (es decir, la aparición de nuevos alelos debido a alteraciones en la secuencia de ADN); 2-recombinación (es decir, el intercambio de información genética entre cromátidas no hermanas durante la meiosis); 3-segregación independiente de cromosomas durante la meiosis (capaz de producir nuevas combinaciones de alelos) y 4-fertilización al azar (lo cual también incrementa el número de combinaciones entre gametos que darán lugar a un nuevo individuo).
Answer:
Fossil records provide evidence of an increase in animal species at the same time that atmospheric oxygen levels increased.
Explanation:
A huge diversification among animal species occurred with the increase in the levels of atmospheric oxygen. The reason why the number of species increased drastically was that a whole new world opened up, the land. The land was open for exploitation and taking over, with every single niche free, so animals diversified and filled in pretty much all of the niches. The fossil records give us clues when this happened, as from only microorganisms there is a sharp rise in complex animals, coinciding with the increase of oxygen levels.
If it wasn't for the increase of atmospheric oxygen though this wouldn't have been possible. The oxygen in the atmosphere enabled animals to breathe on land. Also, it cooled off the global temperatures which were too high before the increase of atmospheric oxygen, making them suitable for life. And last but not least, the atmospheric oxygen resulted in the formation of the ozone layer, a layer that started to act as protection from the UV rays.
Answer:
Cell membrane
Explanation:
It encapsulates and delimits the cell. It controls what goes into the cell and what goes out of it. It holds the cell organelles together. It maintains a homeostasis state.
Answer:
3. haploid; diploid
Explanation:
Sperm is male gamete or often called male reproductive cell. During the process of spermatogenesis, reductional division (meiosis) occurs in the spermatocytes and spermatids are formed which further mature to sperms. Thus as a result of meiosis, their chromosome number is reduced to half and thus they become haploid cells. During oogensis, eggs are also formed as a result of meiosis which reduces the chromosome number and so eggs are also haploid.
When during fertilization, these two haploid nucleus of these cells fuse together, they form a diploid zygote.
A herbivore is vegetarian and will not eat any animal products but an omnivore will eat both plant and animal products.
