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Easter Island. Learning Objectives. Be able to explain what population, community and ecosystem is Know growth curves Interpret graphs Describe how the human population is growing. Chapter 14: Population Ecology. Planet at capacity: patterns of population growth
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Easter Island Learning Objectives • Be able to explain what population, community and ecosystem is • Know growth curves • Interpret graphs • Describe how the human population is growing Chapter 14: Population Ecology Planet at capacity: patterns of population growth Will the biosphere continue to support all of us?
Countries where boys are off balance China Armenia India What is the natural ratio of males to females? _____ males per 100 females
Population ecology is the study of how populations interact with their environments.
WHAT IS ECOLOGY? Ecology is the study of interactions between organisms and their environments. It can be studied at many levels, including: INDIVIDUALS Individual organisms POPULATIONS Groups of same species that live in a specific habitat COMMUNITIES Populations of different species that interact with each other within a locale ECOSYSTEMS All living organisms, as well as non-living elements
In your own neighborhood, which list below defines a biological population? A. The humans living in your neighborhood. B. The humans, and other animals living in your neighborhood. C. The animals (including humans) as well as the plants living in your neighborhood. D. The animals and plants and the type of physical environment around your neighborhood.
Populations can grow quickly for a while, but not forever Giant puffball mushroom There is no exception to the rule that every organic being naturally increases at so high a rate that, if not destroyed, the Earth would soon be covered by the progeny of a single pair. —Charles Darwin, The Origin of Species
Logistical growth Exponential growth Population growth
How to calculate Population Growth Rate • 500 individuals in a population. • In a year 125 offspring are born. • Birth rate is 125/500 or .25 births per person. • If 25 out of the 500 individuals die during the same year, • the death rate is 25/500 or .05 deaths per person. • The growth rate is .25 .05 or .20 individuals per person.
If a population of 100 has 20 births and 10 deaths in a year, what is the growth rate of the population? A. 0.1 individuals per person B. 0.1 individuals per person C 0.2 individuals per person D. 0.2 individuals per person
Population Explosions Israel Experiencing The Worst Locust Plague In 98 Years –March 2-013 http://www.youtube.com/watch?v=BdyMVWntCgg
Population Oscillations (also called Boom and Bust cycles) Some populations cycle between large and small
Most populations of species in nature undergo ____ A. Exponential growth B. Oscillations C. Explosive growth D. Logistical growth
Biotic Factors _____ _____ _____ Abiotic Factors (Environmental) _____ _____ ______ ______ What limits population size?
How many people can earth support? Why does the answer keep increasing? Increase in Corn productivity in the USA 11.5 bushels/acre (1883) 19.5 bushels/acre (1933) 95 bushels/acre (1992)
What We Often Do Not Know when calculating maximum sustainable yield… • Population carrying capacity • Number of individuals alive • Stability of carrying capacity from year to year • Which individuals to harvest
Survivorship curves graphs of the proportion of individuals of a particular age that are alive in a population
World human population: 7 billion Age of Man: Anthropocene "The pattern of human population growth in the twentieth century was more bacterial than primate" E. O. Wilson Because of the limited availability of land for housing, Hong Kong is home to thousands of tall sky scrapers tha thouse its densely packed population. Sixth extinction because of man !!!
Characteristics of a Population 1. Population density # of individuals of a species per unit area of habitat. 2. Population dispersion: Clumped, random or uniform Calcutta: 25,000people/km2 New York: 155 people/km2
Population dispersion Clumped Clumped: most common in nature Random Uniform
Age structure diagrams Growing population - high proportion of young people Stable - roughly equal numbers of people in each age group. Declining - high proportion of older people http://www.ted.com/talks/hans_rosling_on_global_population_growth.html
World population is ___ But popultion growth rate is ___
What is Demographic dividend? Demographic dividend: Increase in economic growth because of an increase in working age population (15 -64 yrs old)
2022 FIFA World Cup in Qatar Ecological footprint is _______ Qatar Reveals Innovative New Stadiums and Unique Cooling Technologies. First ever cooled outdoor sporting event