1. Population Ecology Science 10

2. Definitions Population- a group of individuals of the same species living within a particular area or volume. Population dynamics- changes in a population characteristics determined by a number of possible outcomes. Ex: mortaility, immigration

3. Characteristics of Population Habitat- the place where an organism or species normally lives. Species- organisms that resemeble one another in appearance, behaviour, genetic make-up. Niche – the way an organism occupies a position in an ecosystem including all the necessary biotic and abiotic factors.

4. Population Size and Density Population Size is the number of individuals of a certain species occupying a certain area/volume at a given time. Population Density is the number of individuals of the same species that occur per unit of area or volume

5. Calculations Formula: D= N/S D- Population Density N- Total Number “Count” of that species S- Space occupied by the population

6. Examples: 1. 480 moose living in a 600 hectare(ha) region. D= N / S D=480 moose / 600 ha D= 0.8 moose/ha 2. What is the density of a population of bacteria if there are 1000 bacteria in a testtube of 10mL?

7. Changes in population There are two types of factors which can effect a population: 1. Density independent factors – any factor which does not depend on density eg. extreme storms, fires and floods. 2. Density dependent factors – any factor which does depend on the density eg. Disease, lack of food, predation, and competition. *** Read pages 288-289 Questions 1-4 page 290

8. Measuring and Modeling Population Change Carrying capacity is the maximum number of organisms that can be sustained by available resources over a given period of time. the largest population of a species that an environment can support. Eg. – 100,000 white tailed deer in Nova Scotia These are often shown in graphs -Complete graph on page 291

9. Four main factors that determine carrying capacity 1. Materials and Energy – energy from Sun, water, carbon 2. Food Chains – populations are limited by food supply 3. Competition – demand for resources among individuals 4. Density – amount of available space. Two types of competition Intraspecific Competition – competition among members of the same species – wolves competing with wolves Interspecific Competition – competition between species – lions and tigers competing for food - seals and dolphins competing for food

10. Different types of populations Open population- a population in which change in number and density is determined by births, deaths, immigration, and emigration. Closed population- a population in which change in size and density is determined by birth and death rates!

11. Population Growths A closed population will exhibit exponential growth- a pattern of population growth where organisms reproduce continuously at a constant rate.

12. Open Population Growth An open population will show the following type of growth which is referred to as an S- curve – a pattern of exponential growth at first then a leveling off once carrying capacity is reached.

13. Human Population and Carrying Capacity What is happening to the human population of earth? http://www.npr.org/2011/10/31/141816460/ visualizing-how-a-population-grows-to-7- billion http://www.npr.org/2011/10/31/141816460/ visualizing-how-a-population-grows-to-7- billion Read pages 293-294 Questions 5-7 page 295

14. Ecological footprints Ecological footprints: is a measure of the impact of a human individual or population on the environment. Unsustainable: large ecological footprints and dependence on fossil fuels. Sustainability: modern societies must seek to establish ecological footprints which use water and land at levels which can continue forever.