The three-spined stickleback (Gasterosteus aculeatus) is a fish that is widely distributed throughout the Northern Hemisphere. It is found in coastal marine, estuarine, and freshwater environments. A typical stickleback is long from nose tip to tail, with bony armor and spines for protection from predators. Each spring, male sticklebacks build nests in shallow water. Females lured back to the nest will release their eggs and swim away. Males actively defend the nest and care for developing eggs until the tiny fry hatch. In southwestern British Columbia, six lakes on three islands in the Strait of Georgia of British Columbia are home to three-spined stickleback populations (see Figure 1). Figure 1: Map of central Strait of Georgia showing lakes containing three-spined stickleback populations. Interestingly, each of the 6 lakes contain two distinct populations of three-spined stickleback: a benthic population and a limnetic population. The benthics are stout bodied, wide mouthed, poorly armored, and have few, short gill rakers. These fish forage on the bottom in the shallow margins of the lake. The limnetics are slender bodied, slim mouthed, well armored, and have many long gill rakers. They feed on zooplankton in the open waters of the lake (McPhail 1993a). Refer to Figure 2 that summarizes differences between the two populations
Note: Gill cabers are used to fliter food from the water, As water noven through the gills, the rakex trap organims nuch as planition, cnstaceans, insects, and algoe, Gill retern are ipecialised forl the oppe of food that tho eat. So, the central question is Are these two stickleback populations separate species? Or are they two subpopulations of a single species, specialized to feed in different areas of the lake? 1. Use the above information to create a hypothesis that addresses the central question. Provide rationale. 2. What is the first experiment you would perform to determine if these populations are, in fact, two different species? Refer to your prelab for a definition of species and your previous answer to this question. 3. Predict the expected results of the experiment you proposed in \#2 if your hypothesis is true.