Biodiversity – Nov. 14/12
- There are three components to biodiversity worldwide: 1. Species/taxonomic diversity on earth. 2.
Genetic diversity within species. Each species is a population of genetically similar, but not identical
individuals. 3. Ecosystems.
- What is an ecosystem?: An ecosystem is all of the living organisms of a given area, as well as the non-
living aspects of the area. It is a biological community and its physical environment. Species do not
and cannot live in isolation. Even in a zoo, a species is not living in isolation. It is living in a human
environment and being cared for by humans. Species live in groups called communities, and
communities live in the environment and interact with non-living aspects (sunlight, rain/water, non-
living parts of soil) to form ecosystems. Ecosystems are the most important part of biodiversity
(because species can’t live on their own). An ecosystem is a whole that evolved over geologic time.
Ecosystems can take some stress/loss of component parts, but how much? The earth’s major
ecosystems are called biomes.
- The earth’s first ecosystem was the ocean. The global ocean/world ocean – All marine (salt)waters
are connected. The global ocean is a solitary, continuous ocean that covers most of the earth. The
ocean covers 71-72% of the earth. The ocean is 97% of earth’s water. The global ocean surrounds the
land masses. The dymaxion projection created by Buckminster Fuller in 1954 is the only flat map of
the entire surface of the earth that shows land as islands with the global ocean surrounding it. This
map shows the least distortion of the relative shapes and sizes of the land masses. The continents are
intact. The global ocean is shallow and well-lit in coastal areas and deep and dark far from land
(there are various zones and depths). The maximum depth is 7 miles. The global ocean is a vast deep
ocean. At deeper than 200m (660ft) is 66% of the earth’s surface. The ocean is a habitat for 250,000
species, many of which we eat. It is an important ecosystem unto itself and is integral to all life/all
ecosystems (it is involved in the water cycle and carbon cycle, and it influences climate/weather).
The photic zone in the ocean is where photosynthesis occurs. Photosynthesis does not occur below
200m. So most of the ocean is non-photosynthetic (but heterotrophs can still live there).
- What are some of the remarkable taxa that we have discussed that live in the ocean?: cetaceans
(largest organism ever to have lived on earth), fishes, sharks and rays, molluscs, crustaceans,
horseshoecrabs, microscopic prokaryotes, microscopic plankton (green algae, diatoms,
dinoflagellates), kelp forests/brown algae. Seals, penguins, and polar bears are also found in oceans.
Some groups absent from oceans are vascular plants and insects.
- The ocean is unexplored. 95-98% of the global ocean is unknown, undiscovered, and unexplored.
Much of the ocean bottom is unexplored and unmapped. Mariana Trench is the deepest part of the
ocean. There have been two explorations of it with people and two without people. Xenophyophores
(Chromalveolata: Foraminifera) are found there. It is hard to study them because they don’t survive
when brought to the surface. There could be many new species in the ocean that we are unaware of.
- The ocean is exploited by people. Ocean dumping is the deliberate disposal of garbage into the ocean.
It kills off marine life. Overfishing is fishing particular species/stocks beyond the point where they
are able to re-populate and come back. There are many marine species that are endangered from
- Terrestrial biomes: The tropic of cancer is north and the tropic of Capricorn is south. Between these
two points are the tropics (tropical forest). We live in the temperate deciduous forest. North of this is
the coniferous forest. North of this is the tundra. The tundra biome occurs in the arctic and on
- Latitude is the primary factor that affects the distribution of the terrestrial biomes. The tropics get
the most intense direct sunlight (and more energy) for the longest duration. The equator has more sunlight throughout the year. There is very little seasonality at the equator. As you move nort