Legacies of Human Evolutionary History

Example of my classmate

Example One

c. Describe and discuss some of the consequences of human impact on planet earth. Consider issues of biodiversity, resistant bacteria and the “thrifty gene.”

Humans have had a negative impact on our planet Earth. In the video lesson, Douglas Crews stated “agriculture was a major cultural evolution,” however it has led to the destruction of our planet and has had significant negative consequences. For example, agriculture has led to the destruction of natural habitats of wild animals and birds as land is taken over for farming. To control the pests that result from agriculture, scientists invented pesticides to kill bugs that destroy crops. Unfortunately, the pesticides seep into the earth and air and have unintentionally killed birds and animals. The narrator of the video stated: “we are poisoning the planet at the same time we are eliminating pests.” Humans have also been negatively affected by pesticides because it has impacted the water supply and drinking water. Agriculture has also led to an increased population due to a ready supply of food. An increased population results in increased usage of natural resources and an eventual depletion of these resources. As the population increases, overcrowding also results. With overcrowding not only are there more people but more pollution and waste. Melvin Konner stated: “over population is a threat because the planet can only support a certain number of people. Even if we could put together enough food we won’t have enough resources.”

The video lesson discussed the possibility of the sixth mass extinction event. A mass extinction event is when a large number of species die out in a relatively short period of time. A number of scientists predict humans will initiate this event because humans continue to disregard nature, explode natural resources and destroy animals’ habitats. Humans are in a fight against nature and this fight results in destruction of the planet.

Vocab:

*menarche – the beginning of menstruation in females. Effected by genetic variation and environmental factors.

*menopause – the end of menstruation which occurs in women around the age of 50; appears to be a product of evolution.

*senescence - The process of aging as a disease that should be treated; age related decline in physiological or behavioral function in adults.

*biodiversity –the variation of life at all levels on earth which is almost entirely due to the expansion of the human population and the resulting need for more resources, such as land for agriculture and living areas.

*mass extinction event – when a large number of species die out in a relatively short time – usually with a catastrophic event; ex: catastrophic event millions of years ago that ended the dinosaurs.

Example Two

c. Describe and discuss some of the consequences of the human impact on planet Earth. Consider issues of biodiversity, resistant bacteria, and the “thrifty gene”.

Some of the consequences that humans have impacted Earth is the number of people that are on the planet, biodiversity, and bacteria changing. In the DVD lesson, when the narrator began to talk about overpopulation, it was mentioned that there are about six billion people now. I think that there are more people living longer and the fact that there are advances in medicine can assist humans. All these changes are benefiting humans to some point and in also hurting humans as well because not everyone has the advances in medicine.With this being said, since there are also a lot of people in this planet, the resources are being lessened for both humans and animals.

Some animals are going extinct and it is because there is a lot of changes that planet Earth is going through. Some animals have lost their homes, because the trees are being cut for the benefit of people. Other animals are living in conditions not very beneficial for them to succeed. For example, in the video there were images of a turtle swimming in what looked like a lake with water that had trash. With these animals slowly moving can bring other animals that can affect us, like mosquitoes.

In the DVD lesson it was mentioned that in agriculture, when people grow their crops and take care of their crops, some may use products that are to protect the crops. However, these products that are to control pests are poison. The narrator mentioned that “people are poisoning the planet when we try to kill pests”. So, similar to last weeks discussion post on mosquitoes coming about more, there is a danger when trying to get rid of them. The poison for them may hurt us, and the bacteria that may be brought by pests can adapt. Although our medicine is advancing some diseases just as it was mentioned in the DVD lesson, are alternating like HIV/AIDS and Tuberculosis. The diseases people are treating not curing.

According to Kim R. Hill, the thrifty gene is when “Some populations that have a history of these long-term food famines have evolved a whole bunch of physiological mechanisms to store fat at really high levels because those who didn’t simply didn’t survive the famine periods”. In other words it is a gene that would assist people in storing fat just enough for survival. He discussed that today, that gene is “excited” because people are over eating. So, since people are eating more than the people before, the resources at some point may run out. In the DVD, ancestral diet was mentioned and it referenced the foods that people ate to survive. The fact that the thrifty gene seems to have changed now, this impacts the planet because we use the planet for the resources provided and survival.

Menarche- The beginning of menstruation in females.

Menopause- The post reproductive period in the lives of women, after the cessation of ovulation and menses. (p.433)

Senescence- Age-related decline in physiological or behavioral function in adult organisms. (p.435)

Ancestral diet- According to the narrator in the DVD, “…high on animal protein, complex carbohydrates, fiber, and low in fat and salt”.

Thrifty gene- A genotype that is very efficient at storing food in the body in the form of fat ...(p.403).

Biodiversity-The variation of life at all levels on Earth.

Mass extinction event- According to the narrator in the DVD lesson, "When a large number of species die out in a relatively short time".