Presentation on theme: "Daily Response 1)What is the difference between immigration and emigration? 2)What is a limiting factor? 3)Name 3 limiting factors. 4)What happens to a."— Presentation transcript:
Daily Response 1)What is the difference between immigration and emigration? 2)What is a limiting factor? 3)Name 3 limiting factors. 4)What happens to a population when the birth rate is bigger than the death rate? 5)What happens to a population when the death rate is bigger than the birth rate?
Determining Population Size 4 different techniques scientists use to estimate the size of populations
Direct Observation What is the population of penguins? Count them.
Direct Observation What is the population of seagulls? Count them.
Indirect Observation What is the population of rabbits? Since you can not see the rabbits you have to count the number of rabbit holes. Next, estimate how many rabbits you think live in each hole. Multiply the numbers to get the population size.
Indirect Observation What is the population of birds? Since you can not see the birds you have to count the number of nests. Next, estimate how many birds you think live in each nest. Multiply the numbers to get the population size.
Sampling What is the population of ants? Take a small section of the ant hill and count the ants. Find the total area of the ant hill. Follow the equation below to find the total population of ants. There are 20 ants in one square cm. The ant hill is 100 square cm. 20 ants =? 1 cm 100 cm
Sampling A biologist collected 1 gallon of pond water and counted 50 paramecium. The pond holds 2,000 gallons of water. What is the population of paramecium? 50 paramecium =? 1 gal 2,000 gal
Mark and Recapture This method is most useful when dealing with an animal population that moves around 1)individual organisms are captured (unharmed) 2) They are counted and marked or tagged and then released back into the environment 3) After some time some are recaptured and we count how many have the mark and how many do not
Mark and Recapture http://www.youtube.com/watch?v=AuIRdK5IfNo&f eature=player_detailpage http://wwf.panda.org/what_we_do/where_we_wo rk/arctic/wildlife/polar_bear/tracker/ http://www.youtube.com/watch?v=lKyj7gEAAS8 http://www.youtube.com/watch?v=VRTNQpXEZE4
Journal Entry Explain the four ways we determine population size. Then write your own example for each one. (It may not be the examples from the book, outline or power point.) Direct Observation Indirect Observation SamplingMark and Recapture Explanation - Example -