Population Ecology Part 3 AP Biology Population Ecology Part 3

Carrying capacity for the given environment Population Limiting Factors (All can limit a populations size… could even be more than one at a time.) Resources (This can be food, water, space…if it is a territorial species.) Competition rises as resources become scares draining energy away from reproduction. Health conditions (Such as crowding and disease.) Predation by another species. Intrinsic Factors (Such as aggression, stress, personality issues with humans.) Carrying capacity for the given environment

Boom-Bust cycles of Growth (This describes a Predator/Prey relationship mainly.) Shows the lag-time for other species to adjust to a change in a species population number. The two population “lines” are chasing each other because of their direct relationship. This relationship also promotes natural selection as it will be the strongest that survive and reproduce… so each species is causing the other to evolve… which is referred to as co-evolution.

Boom and Bust Cycles aculty.mdc.edu/mdelcamp/.../2_Pres_Population_Dynamics_pp.ppt

Human Population growth pattern The population explosion that is occurring has changed the dynamics of Earth tremendously. Environmental degradation and over-consumption of resources is occurring. Species loss (extinction) is occurring at a fast rate. Overpopulation is being seen in India, China, and some other Island nation.

Human Growth on Earth

Human Population Growth aculty.mdc.edu/mdelcamp/.../2_Pres_Population_Dynamics_pp.ppt Human Population Growth Human population is following an exponential growth pattern. With the advent of modern medicine, better sanitation, and increased food supplies, the biggest constraints on population growth were removed. At some point in time the world’s population will have to stabilize. The current increases have had many profound effects on the biosphere and its inhabitants.

Human Population Growth 2 aculty.mdc.edu/mdelcamp/.../2_Pres_Population_Dynamics_pp.ppt Human Population Growth 2 Man’s footprint upon the land is great, not just in sheer numbers of individuals, but in the resources they consume. How many items have you used and then disposed of today? There will be limits on the growth of human populations. The question is: Will we manage it ourselves or will we wait for natural forces to do it for us?.

Ethics/Freedom/Control China and India and United States China has imposed laws to get control of birth rates. (These can be found on the internet.) India has not yet imposed laws, but is seeing resource issues currently. The U.S. is not near the size in population as China or India ; but the United States uses most of the world’s resources; which is an issue for China and India and the rest of the world.

Human Growth History The human species started as a Hunter gathers society. (nomads)(Energy?) Their energy mainly went toward following the food so little was left for reproduction (They were basically too tired and health issues also drained energy.) Agricultural Revolution and the plow With the invention of the plow, more food and not having to travel increased health and energy reserves. These could be put toward reproducing… so the population begins to climb. This also leads to the formation of towns and villages.

Industrial Revolution This help lead to cities because now everyone didn’t have to produce their own food, it could be grown in the countryside and trucked into the city for sale. Also this allowed for an increase in reserve energy to put toward reproduction. Also health care improved for most people. Technology Revolution and Medicine Better health causing people to live longer now and survival of babies increases. Women, in general, are having more children because families are becoming more affluent. Technology, while mostly good for society, makes most people less active and puts even more energy toward reproduction and obesity.

Age Structure pyramids These can show the number of individuals at each age group. (called cohorts) These can be used to identify current trends/problems. (life expectancy or Infant mortality) Can be used to identify future trends/problems. More elderly and less young to support them or future unemployment for example.

Age Pyramids Rapid growth Afghanistan Slow growth United States Decrease Italy Male Female Age Male Female Age Male Female 85+ 80–84 75–79 70–74 65–69 60–64 55–59 50–54 85+ 80–84 75–79 70–74 65–69 60–64 55–59 50–54 45–49 40–44 35–39 30–34 25–29 20–24 15–19 10–14 5–9 0–4 45–49 40–44 35–39 30–34 25–29 20–24 15–19 10–14 5–9 0–4 8 6 4 2 2 4 6 8 8 6 4 2 2 4 6 8 8 6 4 2 2 4 6 8 Percent of population Percent of population Percent of population