Biological Sciences 2B
Welcome to Biological Sciences 2B.
BIS 2B is the second course in the Biological Sciences lower
division core sequence that is designed to provide a foundation for study of modern biology for
a broad range of majors.
Whereas BIS 2A introduced you to the fundamental molecular,
cellular, developmental, physiological, and genetic building blocks of living organisms, and the
origins of life itself, BIS 2B picks up the story by examining ecological and evolutionary
processes that shape biological diversity.
Specifically, this course covers the processes by which organisms have evolved over the several
billion years of the existence of life on Earth (
) and the present-day processes by
which those species interact with each other and the environment to create the patterns of
distribution and abundance of species we see around us (
As you will certainly see
throughout the quarter, evolution and ecology are fundamentally linked: evolutionary history
shapes a species’ ecology, and present-day ecology can influence future evolutionary
This is why we present them here together.
What is Ecology?
Ecology is the study of the interactions (either between organisms or
between organisms and their environment) that determine the distribution and abundance of
Ecology can be thought of as studying several hierarchically nested levels: the
individual organism, a population (consisting of many individuals of the same species), the
community (consisting of populations of many different species), and the ecosystem (the
community plus the physical environment that surrounds it).
Ecology is NOT about hugging
trees and saving the whales.
It IS about the scientific study of those whales and trees and the
factors that determine where they occur on the face of the Earth and why they are more
abundant in some locations than in others.
What is Evolution?
Probably no one put it better than Doug Futuyma, in his classic textbook on
“In the broadest sense, evolution is merely change, and so is all-pervasive; galaxies, languages,
and political systems all evolve. Biological evolution .
.. is change in the properties of populations
of organisms that transcend the lifetime of a single individual. The ontogeny of an individual is
not considered evolution; individual organisms do not evolve. The changes in populations that
are considered evolutionary are those that are inheritable via the genetic material from one
generation to the next. Biological evolution may be slight or substantial; it embraces everything
from slight changes in the proportion of different alleles within a population (such as those
determining blood types) to the successive alterations that led from the earliest protoorganism to
snails, bees, giraffes, and dandelions."
And, as one of the great evolutionary biologists, our own Theodosius Dobzhansky, famously
said in a 1973 essay, “
Nothing in biology makes sense except in the light of evolution