Question 1. Amphibians (e.g., frogs, toads, and salamanders) are declining world

Question

Question 1. Amphibians (e.g., frogs, toads, and salamanders) are declining worldwide. Two hypotheses for why this is happening are predators and pesticides. To test these hypotheses, scientists raised several frog species as tadpoles in small ponds (n-5 per treatment combination). Ponds had either no predators, predatory newts, or predatory beetle larvae; in addition, ponds were exposed to either no pesticide (NP), the insecticide Malathion (M; kills insects) or the herbicide Roundup (R; kills plants), two globally common pesticides. The researchers then monitored subsequent survival of the tadpoles in each pond. Consider the following figure; different letters denote statistically significant differences between groups (Tukey's HSD; P

Explanation / Answer

Answer A.

Independent variables are those variables which are controlled by the experimenter. Dependant varaiables are those which are not controlled but depends on independent valriables. I this experiment, there are 6 indipendent variables (no predators, Newts, Beetles, NP, M, and R) and 1 dependant variable (life expectancies of tedpole).

Answer B.

There are 9 treatment combinations in the expermental design (no predators-NP, no predator-M, no predators-R, Newts-NP, Newts-M, Newts-R, Beetles-NP, beetels-M and beetles-R). There are three control groups (no predator-NP, no predator-M and no predator-R).

Answer C.

Experimental unit in this experiment is %survival and there are 5 replicates of each treatment combinations(n=5).

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