There's no reason to think that human beings in ancient times were any simpler or stupider as a group or as individuals than they are today. They did have a much smaller pool of accumulated knowledge to build upon, so you might say that they were more ignorant than we are today.
But certain aspects of humanness were undoubtedly just as powerful then as now: the need to know why things happen the way they do, and the need to break information down into manageable and useful bits, and the need to label things, place them in categories, and explain their relationships. Of all the abilities humans have in different amounts than other animals, it may their greater sense of connection, particularly of how cause relates to effect, that really is the basis of science.
You can see aspects of human organization in how people have investigated Nature - we look for family, tribe, and nation types of relationships, in patterns that match the patterns in our societies. If Modern Science is a product of "Western Society" - which is arguable, of course - its intrinsic patterns may just be an outgrowth of the level of structure and coordination and planning needed for a continent of cities and the support infrastructure that allowed those cities to interact meaningfully with a globe of trade. Isn't the organization of one remarkably similar to the organization of the other? Is that a coincidence, are there many varied ways to perform "science"?
The ideas of PostModernism, which are applied to everything from art to politics to science, deals with the idea that all human endeavors and discoveries take forms which must be influenced by the cultures that produce them. In science, they argue that the classic approach, the Scientific Method, is just one way to determine how the world works, and that other cultures are free to find their "truth" in other ways. Western science supporters argue back that the strong role of logic (based on math, which really doesn't
show cultural variance) in science sets it apart from
other disciplines - but then, they're coming to the
defense of something they strongly believe. It is
never bad to remember, however, that science is made -
or at least interpreted - by the scientists, who
(whether they like it or not) are products of their
cultures. All of the major ideas of science, from
Lamarck and Darwin through Einstein and Margulis and
Hawking, have a bit of each person's world and worldview
embedded in them.
Early Biology is a mixture of a need to understand the practical - humans had a practical grasp of genetics millennia before Austrian monk Gregor Mendel began to work out the details - and a compulsion to see the Big Picture. From a simple level, as the concept that a dog, a wolf, and a fox were different types of animals but could be joined together in the smaller but definable type of Canines, to a larger but understandable concept that living things with similar forms and functions could be placed in groups together - the creatures of the water, the creatures of the air, the slithering legless things, the things that grow from the ground, et cetera. It seems a simplistic way of grouping things together, but one suspects that it was convenient, and that the ancients who really used the system probably realized that it had some limitations, as users of today's systems do.
Early on, the major groupings of living things were two simple broad groups: the Animals, things that moved and ate, and the Plants, which didn't move or appear to eat (plus the minerals, which were not as obviously unliving as we see them today). The methods by which living things were classified (an aspect of biology called taxonomy) were not widely coordinated until the 17th and 18th Century, culminating in the development of the binomial nomenclature system by Carolus Linnaeus in the mid-1700s.