Evolution & Ecology: Natural selection, Gene flow, Speciation, Drift

Humans have a large impact on the environment—pollution, land use change, climate change, etc. We are just beginning to realize that we also cause evolutionary change, and the consequences of this. Ecology and evolution are strongly interconnected. What Is Evolution? Evolution can be viewed as genetic change over time or as a process of descent…

Coping with Environmental Variation: Temperature and Water

The physical environment influences an organism’s ecological success in two ways: Availability of energy and resources—impacts growth and reproduction. Extreme conditions can exceed tolerance limits and impact survival. Energy supply can influence an organism’s ability to tolerate environmental extremes. The actual geographic distribution of a species is often lower than potential distribution due to other…

Forms of Sexual Contraception & Types of Abortion

Contraception Combination Pill: Birth control pills that contain a combination of estrogen and progestin (progesterone) (21 days on, 7 placebo) The pill works by preventing ovulation; keeps estrogen high inhibits LSH and no ovulation; high progesterone inhibits LH . Keep endometrium lining thick and prevents sperms from effectively travelling Failure Rate: percentage of women who…

Diphtheria (Corynebacterium diphtheriae): History, Symptoms, Causes, Treatment

Corynebacteria are Gram-positive, aerobic, nonmotile, rod-shaped bacteria related to the Actinomycetes. They do not form spores or branch as do the actinomycetes, but they have the characteristic of forming irregular shaped, club-shaped or V-shaped arrangements in normal growth. They undergo snapping movements just after cell division which brings them into characteristic arrangements resembling Chinese letters.…

Huntington’s Disease: Causes, Symptoms, Testing

Huntington’s disease, or Huntngton’s chorea, is a genetic disease that causes selective neural cell death, which results in chorea, or irregular, jerking movements of the limbs caused by involuntary muscle contractions, and dementia.  It can cause a lack of concentration and depression.  It also may cause atrophy of the caudate nucleus, a part of the…

Osteoporosis: Causes, Symptoms, Treatment

Osteoporosis is a significant health problem that affects more than 25 million women in the United States and potentially 200 million worldwide. This disease is characterized by diminishing the structure of the skeleton (particular the “spongy” bone). This results in an increased risk of fracture. Osteoporosis develops silently over a period of years, eventually progressing…

Premature Infancy & Infants: Causes & Treatment

Premature babies, otherwise known as preterm babies, or preemies, are babies that are born earlier than the full-term of thirty-eight to forty-two weeks of pregnancy. These babies are generally born between the twentieth and thirty-eighth week. Almost 250,000 babies, nearly seven percent of newborns, are premature(Golant 4). Prematurity, even with all the advances in technology,…

Reye Syndrome: Causes, Symptoms, Treatment

Reye Syndrome is an extremely rare, non-contagious disease thought to be triggered by aspirin use.  The actual origin of the disease is unknown.  Reye’s Syndrome, occasionally called Reye-Jacobsen’s Syndrome, is known to follow any viral infection.  Two of the most common viral infections it precedes is influenza, “the flu”, and chicken pox.  A now-familiar warning…