Demography In Biology

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1. Demography is a discipline in Ecology that deals with population measures such as, age, size and overall structure are critical to demographic work. Demography is used to help understand a populations growth pattern, although not all individuals are the same age and size or have the same survival and birth rates. Demography allows for greater depth and detail of a populations structure to be characterized and analyzed.

2. There are two methods for collection demographic data, static and dynamic. The static method of collection, also known as time specific, looks at existing populations and classifies age classes from samples of individuals living a population (inventories). This method also includes looking for evidence of dead organisms
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Survivorship is the number or proportion of individuals from the newborn class surviving to the timeframe of interest. Survivor rate is the number or proportion of individuals surviving from year to year. Survivor rates are a “one time” step change, meaning time is measured in increments.

4. Fecundity is the number of offspring produced per reproductive event (per gestation/clutch/pollination). Fecundity provides information about the birth rate of an organism. Many factors can influence the fecundity of a species including: age, resources available, parental investment, r and k species.

5. There are many methods for aging an individual including: size, instars/stages of development, carbon dating, teeth, and birth/death
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Wherein, mortality is roughly the same for both males and females from the mid-fiftes into the early nineties. However, disparities of mortality rates in particular age classes does differ between males and females. Most notably males are more likely to die in their twenties and then again in their fifties than females are. Yet, females are more likely than males to die in their early teens and forties; however, they are more likely to outlive men from the ninnies and upwards (approximately 110). The behaviors and physiological differences between males and females is likely to influence the risk of dying at a particular age and can be explained by biological and social factors. For example, men in their twenties are more likely to be active in the military and exposed to war/potentially life threatening situations. Whereas, a variety of medical conditions are likely to become problematic at certain age classes. For example, men are likely to be diagnosed with chronic diseases at age 50. Early childhood death for females could be due to increased exposure to infectious diseases or unintentional injuries. Whereas, the death of females in their late forties could be due to
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