1. The passing of traits from parents to the offsprings (children) is the basis of heredity. Traits are notable features or qualities in a person, such that each individual has a different combination of traits that makes us unique from others. They are inherited from our parents and passed from generation to generation. That is to our children, then our children to their children and so on.
2. Our genes encode the instructions that define our traits. Traits are majorly defined by the instructions encoded in the genes. However, environment may influences the traits and may play an important role in shaping the traits we posses. Often times these traits may be changed by the environmental factors.
3. Each of us has thousands of genes, which are made of DNA molecules and reside in our chromosomes. Genes are functional or fundamental units of heredity. They are made up of DNA molecules, and act as instructions to make proteins, through a process of transcription and translation. Transcription involves formation of a messenger RNA which then undergoes translation in the cytoplasm to make proteins.The protein formed determine the traits of an individual.
4. In addition to our genes, the Environment we live in also helps define our traits. The expression of genes in organisms may be influenced by environmental factors, these includes the external factors where the organism lives or develops, and also the internal factors such as its hormones and metabolism.
5. Human have two complete sets of 23 chromosomes. A human being has a total of 46 chromosomes (23×2 = 46). This is referred to as a diploid number (2n). Each set is considered to be a one homologous chromosome set. This is the case of of the somatic cells or the body cells which represents a diploid number of chromosomes.
6. When parents conceive a child, each parent contributes one set of chromosomes.This enhances the passing of traits or genes to the child. The egg cell or the ovum from the mother and the sperm cell from the father contain the haploid number (n) or one set of chromosome. During conception the two combines/fuse to form a zygote which is now diploid (2n).
7. Every child receives half of its chromosomes from the mother and another half from the father. During meiosis in the gametes for both mother and father a haploid cell is formed with one set of chromosomes (haploid, n). Therefore, each child contains half number of chromosomes from the mother and the other half from the father making up the diploid number (2n).
8. This transfer takes place at conception, when the father's sperm joins the mother's egg. During conception, fertilization takes place and the sperm cell fuses with the mother cell (ovum) forming a single cell called Zygote. The zygote has the two sets of chromosomes (23 +23 = 46). The cells then divide by mitosis leading to the development of a child.
9. While most cells in our bodies have two sets of chromosomes, or a total of 46 chromosomes, egg and sperm each have 23 chromosomes. The body cells (somatic cells) contain two sets of chromosomes (diploid number, 2n) from mitosis, while the gametes have a single set of chromosomes (haploid, n), from meiosis.
Answer:
Climate change not only affects ecosystems and species directly, it also interacts with other human stressors such as development. Although some stressors cause only minor impacts when acting alone, their cumulative impact may lead to dramatic ecological changes.
Explanation:
Answer:
Date and latitude interact to determine photoperiod, the daily period of daylight. This interaction has important implications for latitudinal migrants for whom daylight may be a resource or for whom photoperiod regulates annual transitions in life‐history stages (i.e. birds).
Using an established formula, we developed user‐interactive, animated models that enable the visualization of how latitude and date determine photoperiod for latitudinal migrants. We also calculated the photoperiodic schedules for a broad range of hypothetical migratory programmes and real migratory programmes newly available through the proliferation of citizen‐science data. This enabled us to infer the limitations some migratory programmes place on mechanisms for photoperiodic regulation of annual breeding.
In the vast majority of cases, the act of migrating elevates annual daylight exposure. This raises the hypothesis that daylight availability selects for latitudinal migration, potentially contributing to its evolution in animals such as diurnal birds with limited time during the spring and summer to feed young. However, photoperiodic mechanisms regulating annual cycles could constrain the evolution of such migrations, depending on how they affect photoperiodic schedules. Most migratory programmes are consistent with known mechanisms of avian photoperiodism, but the range of feasible mechanisms declines for transequatorial migrants, which experience semi‐annual, 180°‐phase‐shifts in their photoperiodic cycles.
Understanding photoperiodic constraints on migration are particularly important in this age of changing latitudinal distributions and phenologies driven by climate change.
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Answer:
The correct option is A) Many of the younger married couples in Italy are deciding to have less children.
Explanation:
As we know the birth rate of a country should be equal to the death rate of the country in order to maintain a stable economy. In the past, people were not concerned about the rising population and hence did not look upon child birth rate. But nowadays, the younger population is more concerned about the rising population and hence tends to take more steps to control the population.
false is your answer............