Aristotle's scala naturae was a linear classification system that influenced Western thinkers for thousands of years (some would argue it still does). In this classification system, each species occupied a link in a chain that became increasingly complex. Scala naturae did not recognize the shared degrees of complexity among organisms or the ability of species and taxa to change. Which of the following is an example demonstrating that organisms have shared degrees of complexity?
A) A population of fish become separated by a new dam structure; after 20 years the fish living in the shallower, warmer water at the base of the dam can no longer mate with the fish living in the deeper, colder water behind the dam.
B) A virus infects a population of black-footed ferrets and kills 60% of the animals. The remaining 20% are immune to the disease; the offspring of this group are 90% immune to the virus.
C) Due to earlier spring warming resulting from climate change, temperate woodland wildflowers bloom an average of nine days earlier.
D) Nostoc (a cyanobacterium) and Helianthus (sunflowers, a vascular plant) have chloroplasts and conduct photosynthesis.

Question

Quizplus · Accepted Answer

Nostoc, a prokaryotic cyanobacterium, and Helianthus, a eukaryotic vascular plant, both have organelles called chloroplasts that allow them to conduct photosynthesis. This demonstrates that even though these two organisms are very different in many ways (e.g. prokaryotic vs eukaryotic, unicellular vs multicellular), they share a similar level of complexity in their ability to perform this essential biological process.

Aristotle's Scala Naturae Was a Linear Classification System That Influenced