PopulationBiology


 * __ Population Biology __**

· ** You will explain how populations grow [|Population Growth Around the World] ** o Populations depend on water, food, space, and other abiotic and/or biotic factors. These factors will affect the growth or decline of the population. How a population reacts to an environment also affects the growth of it. [|Abiotic and Biotic Factors Video] Examples of Abiotic Factors: (Hurricane & Drought) [|Abiotic Factors Video] Examples of Biotic Factors: (Sickness & Old Age)
 * __ What You’ll Learn __**

o Populations must reproduce to grow. If no reproduction takes place, no growth will occur. o A growing population starts out slowly. This is because the number of reproducing individuals is small. Then it grows rapidly (because the total number of individuals that are able to reproduce has increased) creating a J-shaped curve. o As a population gets larger, it grows at a faster rate. · ** You will identify factors that inhibit the growth of populations [|Population Video] ** o Scientists have observed that population growth does have limits. o Limiting factors such as availability of food, disease, predators, or lack of space can cause the growth of population to slow down. [|Demographic Transition Model] o With this pressure, the population could stabilize. This would create an S-shaped growth curve. o An environment can only support a certain amount of organisms. If the number of organisms goes over the carrying capacity, the population growth will decrease. o Reproductive patterns also affect the growth of populations. Smaller organisms usually reproduce quickly and produce a lot of offspring (these organisms often mature rapidly and have a short life span). Larger organisms have a slow rate of reproduction and produce few offspring (these organisms have long lives and mature slowly) o Some factors have a larger affect as the population increases (density-dependent factors). Factors such as disease, competition, food, etc. Other factors affect populations regardless of the size (density-independent factors). Things such as volcanic eruptions, temperature, floods, major habitat disruption, etc. (mainly abiotic factors).

o Also, the way organisms interact with each other affect the population. Predation, competition, and overpopulation can all affect a population.

· ** You will summarize issues in human population growth ** o Human population can be affected by all of the previously mentioned growth factors. Food, disease, natural disasters, overpopulation, etc. o At first, the human population grew slowly. But eventually medical revolutions helped get rid of diseases and more dependable food sources were found. This resulted in rapid population growth which still continues today. o Different countries grow at different rates because of different economic, social, and environmental issues. Also age structures are different within different countries. · ** Compare and contrast exponential and linear population growth ** o Exponential and linear population growth both demonstrate change in population growth. [|Exponential Growth Equation Video] o Exponential growth means that when a population gets larger, it grows at a faster rate. On a graph, this growth would appear as a J-shaped curve. [|Exponential Growth Video] [|**Earth Overpopulation Video**] o Linear growth says that the growth of a population is the same throughout time. On a graph, this growth would appear as a straight line with a slight incline that grows. · ** Relate the reproductive patterns of different populations of organisms to models of population growth ** o Most populations of organisms on the planet follow an exponential growth. o Most populations start out slowly. As time progresses, more organisms will have the ability to reproduce which will cause a dramatic increase in the population. o Ex: humans, rabbits, etc. · ** Predict effects of environmental factors on population growth [|Effects of Overpopulation Video] ** o Most environmental-altering factors will have an impact on a population and its growth. It will restrict the ability for a population to thrive in its environment. [|Another Overpopulation Video] o For example, if a flood occurs, the environment will be flooded. Many organisms could drown and the population would decrease. This would mean that fewer organisms could reproduce resulting in lower population growth. Also resources would be harder to access.
 * __ Objectives __**

· [|**Population**]- a group of organisms of the same species that live in a specific area · [|Exponential Growth]p opulation resemble a J-shaped curve · ** [|Carrying Capacity] ** - the number of organisms of one species that an environment can support indefinitely · ** [|Life-History Pattern] ** - organism’s reproductive pattern
 * __ Vocabulary __**

 ·[|Density-Dependent Factors] Density-Dependent Factors - limiting factors such as disease, parasites, or food availability that affect growth of a population · ** Density-Independent Factors ** - factors such as temperature, storms, floods, drought, or habitat disruption that affects all populations, regardless of their density Bacteria are examples or rapidly reproducing organisms. They are often used in experiments about population studies or trends. Here are some facts regarding unchecked bacterial reproduction: 1. A single bacterium can reproduce to yield two bacteria under ideal conditions every 20 minutes. 2. Ideal conditions for bacterial reproduction include proper temperature, unlimited food, space to grow, and dispersion of waste materials. 1. ** Calculate. ** Suppose you start with one bacterium under ideal conditions. If no bacteria die, compute the number of bacteria present after one hour, five hours, and ten hours. 2. ** Predict Trends. ** What environmental factors might affect a bacterial population’s reproduction? 3. ** Infer. ** An elephant reproduces once every four to six years. Why are elephants not likely to be used in laboratory population studies? ** Problems-Solving Lab 4.1 ** ** Predict: How rapidly can bacteria reproduce? **
 * __ Interactive Activity __**
 * Solve the Problem **
 * Thinking Critically **

** [|**Population Crossword**] **