Distribute yourselves! Plant in the desert – need to have your roots reach water. Poison arrow tree Algae in deep ocean Mushrooms on a rotting log Mayfly mating frenzy
Spatial relations 1. Clumped 3. Random 2. Even/Uniform Distribution of individuals within a population how individuals are arranged in space Random Not random ---Even/Uniform ---Clumped Which is most common?
Non-random – Clumped “Patchy” Physical, chemical, and environmental conditions Hiding places (prey or predators) Limited dispersal of juveniles, seeds, larvae, baby birds Social Factors Selfish herd Family groups
Non-random -- Uniform Distances between individuals are maximized strong competition for a resource Ex. Allelopathy Other examples? nest distribution of blue tilapia in sewage treatment ponds creosote bushes in southwest
Random The location of one individual bears no relationship to the locations of other individuals Usually found: in homogeneous environments individuals neither attract nor repel one another
Distributions may change: seasons as resources change spatial scale is very important
Do t test to test if the R value is ‘significantly different that 1 (at alpha level of 0.05)
Variance/mean ratio method Colocasia esculenta (Araceae) 50 hoop tosses (for our class) COUNT NUMBER OF PLANTS
Variance/mean ratio method If v/m near 1 random If v/m <1 even distribution If v/m >1 clumped TEST for significance using t test
Interspecific association At same time as above, record presence or absence of species B in quadrant. Justicia americana (Acanthaceae) 50 hoop tosses (for our class) For each hoop toss, record presence or absence of each species
Interspecific Association Record number of hoop tosses in each category (W,X, Y, Z) N = number of total hoop tosses If W x Z > X x Y, positive association If W x Z < X x Y, negative association Do Chi-squared test
You will be doing this worksheet at home. *Remember this sheet is worth 15 points Pgs. 147-148 in the lab manual Do not do computer version on bioviewer!
Due Wednesday 1. Spatial Relations datasheet (pgs 147-148 using data collected in lab Saturday) (15 pts). 2. Quiz 4 -- Do quiz bank questions OR improve one of the WIKI articles (turn in paragraph explaining briefly what you did) OR take quiz at end of lab on Spatial Relations. (5 pts) 3. Population Ecology PRE-LAB (pgs 129-130) (5 pts)