Our lives begin from the conception after fusion of two cells that is why a woman who carries a baby is said to be in a family wear until they are at term. An expectant mother gets proper antenatal care to protect herself and her unborn child until there is need to go to the hospital for the delivery of her new family member, she receives her new born baby with joy a home coming event, something to write home about from a faraway land sending pictures to express the joy of the season. The period between birth and death of a living thing is their life especially for the humans and during this period there is a need to maintain your vitality, keep your form, get energy and renew or recreate for more energy, maintain your vigor. Life expectancy is a statistical measure of the average time an organism is expected to live; the life expectancy for the World in 2020 is 72 years. Life expectancy is shorter for male than for female when narrowed down but a good life expectancy should be 90 if you are on regular medical attention that is going for routine check up and taking advice based on changing times and arising situations. All living things on earth have adapted to our atmosphere which means all living things need our mix of atmospheric gases; that is why all must realize that climate change and global warming will soon be a catastrophe if we all are not careful and vigilant. Life elsewhere would be specifically adapted to their own conditions such in Mars compared to Earth; water is a really important ingredient to sustain the kind of life we know on earth. There is currently no consensus regarding the definition of life, one popular definition is that organisms are open systems that maintain homeostasis are composed of cells have a life cycle undergo metabolism can grow, adapt to their environment, respond to stimuli, reproduce and evolve.
Genes, alleles and chromosomes are the basic units that transmit traits, height such as tall and short as well as the sickle cell trait. Mutations are variations and deviations from the normal due to the changing times. Genetics is the study of heredity and the variation of inherited characteristics; genetics forms one of the central pillars of biology and overlaps with many other areas such as agriculture, medicine and biotechnology. Evolution is the outcome of mutation, genetic recombination, chromosomal abnormalities, reproductive isolation and natural selection. Human evolution is within the history of primates that has led to the emergence of the Homo sapiens as a distinct species of the hominid family which includes the great apes. The first humans “Homo habilis” which means “handy man” lived millions of years ago whereas modern human has originated from a recent common ancestor “Homo erectus” which means “upright man”.