Chapter 34 Lecture Outline
A Mysterious Giant of the Deep
The ocean is a very special environment.
Exploration of the ocean’s depths requires special submersibles such as Alvin, seen in
Figure A. Unusual new species, such as giant squids have been discovered at these depths.
Continental drift and the location of crustal plates (Modules 15.3).
Off the coast of Baja California between crustal plates, at depths of more than a mile and in
complete darkness, hydrothermal vents release hot, nutrient-rich gases (Figure B).
Around these vents are groups of organisms, the most obvious of which are large, yard-long
tube worms. A variety of other animals, including shrimps, crabs, clams, and a few fishes,
also live here (Figure C).
Most of the prokaryotes in hydrothermal vents are chemoautotrophs (Module 16.11).
Ultimately, all the other organisms depend on the food made by these prokaryotes because
energy sources dependent on sunlight never make it in any appreciable quantity to these
This setting hints at many of the topics concerning populations, communities, and nutrient
cycling that ecologists study.
is the scientific study of the interactions between organisms and their environments.
Dealing with humankind’s gravest biological crises hinges on a firm understanding of
This unit starts with an overview of Earth’s different biological settings, details the
principles and mechanisms of ecology, and ends with a discussion of the impact of human
societies on the biosphere.
Ecologists study how organisms interact with their environment at several levels.
The hierarchical organization of life (Module 1.1) and the scientific process (Modules 1.7
level, the focus is on how an individual organism interacts with aspects of its
immediate surroundings through either its physiology or behavior (Figure 34.1).
level, ecologists focus on functioning among all the members of an
interbreeding group within a particular geographic area.
Studies at the
level focus on all the organisms of all species and their interactions
within one particular area.
level of study adds the nonliving factors (
temperature, energy, water, inorganic nutrients, and other chemicals) to the picture, in addition
to relationships among the living factors
Ecology can be enormously complex because it studies multidimensional problems. Ecological
research still employs the scientific process (hypotheses, tests, and observations) but must often