 3000 Km off the coast of Chile  5 th century – 400 people  Created Moai…had food and war was unknown  Several centuries later…15000!  Not enough food…rats introduced… destroyed the forest! Video clip - Attenborough Explains Easter Island

ARE YOU READY…PAGE 646!! What can be learned from this?

 Habitat: place where organisms/species normally live  Species: Organisms that resemble one another in chemistry, appearance, behaviour, and genetic makeup, which have the ability to interbreed with each other to produce fertile offspring

 Population size: refers to the number of individuals of a particular species that occupy a given area or volume at a given time  Population Density: refers to the number of individuals of the same species that occur per unit area or volume.

 D = Population Density  N = total numbers counted  S = space occupied by population  Example: 600 deer living in 620 hectare region of a conservation park would be calculated as follows…

 Small organisms usually have higher population densities than larger organisms  Population density can be difficult to establish due to unusable space within a habitat, so ecologists use two different forms of calculations…

 Crude Density: the number of individuals of the same species per total unit area or volume  Ecological Density: number of individuals of the same species per unit area or volume actually used by the individuals.

Environmental conditions differ throughout a population’s geographic range causing population dispersion of organisms within a population to vary throughout the range!

 Is the general pattern in which individuals are distributed through a specific area  3 main dispersion patters in wild populations ◦ clumped (most common – organisms densely grouped in areas of habitat with favourable conditions) ◦ uniform (individuals evenly distributed throughout habitat) ◦ random (individuals minimally influenced by interactions with other individuals; habitat conditions virtually uniform)

 Most populations are dynamic  Numbers and geographic locations change over time  Sample of the population used to estimate population size and density using variety of sampling techniques  Why Measure?  Conservation strategies, harvest rates etc

◦ Quadrat is a sampling frame used for estimating population size for large areas.  number of individuals counted within each quadrat  total population size estimated via calculations within a representative area  most effective for stationary species  Page 654…

 Used for mobile populations  Sample of animal captured, marked, released,  After time to allow animals to mix randomly with unmarked animals in populations, second sample captured  Marked to unmarked in second sample used to estimate size of entire population M (Total Marked) = m (# of recaptures) N (Total Pop) n (size of recap sample) N = Mn m N = Mn m

N = Mn m N=? M=26 n = 21 m = 3 N = 26 x 21 3 N = 182 N = Mn m N=? M=26 n = 21 m = 3 N = 26 x 21 3 N = 182

 Mark-Recapture Demo  Page 567

 sample of animal captured, marked with radio collars, satellite-linked devices, etc.  animals tracked for their migration and behaviour patterns across their geographic range  Ethics… ◦ CCAC…Reduce, Refine, Replace

 Page 651 # 1-3  Page 654 # 4  Page 657 # 5  Page 659 #1-4

 Part 1 – Quadrat Study (Allergy Alert!!)  Devise your own method  Calculate density per square meter and Total number of dandelions  Answer Analysis and Evaluation questions (f-j)  Part 2 – Mark-Recapture Study  Devise your own method  Answer Analysis and Evaluation questions (n-r)