Note-Taking Scavenger Hunt: Biodiversity and Evolution
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Diversity is the most commonly thought of biodiversity, and is the species richness in an
area. The other types of diversity include ecosystem diversity, functional diversity (a type of biodiversity
that includes nutrient cycles), genetic diversity, and cultural diversity.
Decomposers, such as earthworms are an important part of a biodiverse area because they help
to preserve the
of the soils. Ladybugs, and tree frogs help control populations of
naturally.
Scientists say the first life on Earth was
, or organisms belonging to the bacterial kingdoms
of life. Work done by
and
in the 1800s helped to explain how life diversified from these
simple one-celled organisms to the complex multicellular animals and plants we have today on Earth.
The mechanism of evolution is put forth in the theory of natural selection, which goes like this: First
there is a
, which includes competition for resources in populations that contain many genetic
variations. Some of these genetic variations allow organisms to outcompete others within the
population. Those that survive pass their traits on to their offspring. Those that don’t compete
successfully,
without reproducing. Over millenia, traits that help organisms survive are selected
for naturally, which is why we call it
Nature does not
the evolution, it simply
the traits which are useful at that time.
Currently, there are about
million species observed and documented on Earth, however,
we are far from finished classifying! Of all the kingdoms of life, by far, the most organisms are named
and classified within the kingdom
, followed by
.
The oldest record of life on Earth is in the fossilized remains of
. Fossils are
or
petrified replicas of skeletons, bones, teeth, shells…etc. Not every organism forms fossils, and some
that do form are destroyed in the rock cycle, when sedimentary rocks are “recycled” into igneous and
metamorphic.
are scientists who recreate our past using fossil evidence.
Evolution occurs in
, not individuals. It occurs through Natural Selection and
.
The genetic variations are created randomly by
while DNA is replicating. Some errors can help
organisms adapt to their environment, and some are detrimental. Cells that change could have been
exposed to agents that cause mutations, called
, like ultraviolet sunlight and chemicals. It is the
mutations that occur in our
cells that can be passed on to the next generation, not our
or
body cells.
While
,which enable us to be manually dexterous, and the ability to walk upright
have given us advantages in our environment, by far, the greatest adaptation is our
.
Natural selection is not the be-all, end all of evolution. Sometimes there are factors that limit
the ability of natural selection to foster change in organisms. For Natural Selection to work, the trait
must actually exist in a
first, and then, reproductive capacity could trip up evolution. Organisms
with very
life cycles have more of an ability to evolve rapidly, than organisms with extremely
life cycles, because they simply produce more offspring which have the capacity to produce more
mutations. Geological processes, such as plate
can also influence the environment, which in turn
influences evolutionary processes by selecting traits that are best suited for that particular environment.
Note-Taking Scavenger Hunt: Biodiversity and Evolution
Catastrophic events can often influence evolution. Tectonics near the end of the Permian Period
in our geologic past formed a vast
, making adaption difficult, leading to the Permian Mass
Extinction. Much colder periods include the
during the Proterozoic Eon on Earth. Whenever
there is a catastrophe, a high degree of
is what allowed life to continue on Earth.
Whenever a new species emerges, the process is called
. This can happen in a few ways
that you must be aware of. When geography itself provides a barrier, such as an ocean, or landmass, or
even a river…
isolation has occurred. This encourages speciation. When a species becomes
isolated, something occurs which prevents mating and producing offspring successfully together.
Reproductive Isolation occurs when the time of year for mating is different.
Reproductive
Isolation occurs when the right parts don’t match up any more…making
physically impossible.
Isolation occurs when mating rituals don’t attract mates anymore.
is a natural process which affects biodiversity levels on Earth. It occurs when the last
surviving individual of a species is gone. Over
species each year becomes extinct. The most
vulnerable to extinction are
, because they are only found in one secluded area.
are
particularly susceptible because part of their respiration occurs across the moist membrane of their skin.
This makes them doubly susceptible to toxins in the air.
extinctions are rare, with only five having
occurred over the vastness of geologic time. They occur when global catastrophic events cause large
groups of species to be wiped out.
extinctions are occurring continually, and exhibit relatively low
rates of extinction. The one plus that occurs during mass extinctions is that it gives new species the
opportunity to thrive in the new
and
left by the now extinct organisms.
A
is an ecological role played by an organism. Many people confuse niche with
, but
that is actually where an organism lives. A niche can be anything from the dietary needs of a species
(carnivore, omnivore, herbivore), to the temperature or daylight a species needs. A species can either
be a
with a very diverse diet, such as a raccoon, or a cockroach, or a
, such as a Koala.
Koalas only eat eucalyptus and have difficulty adapting if the eucalyptus dies out. For this reason, many
have difficulty dealing with changing environments. It is much better to be a
when it comes
to changing environments.
Native species are those which are
, or that normally live in an ecosystem. Non-native
species are also known as
, or invasive, because many times they thrive in their introduced
environment as they have no predators.
are used to gauge the relative health of an ecosystem. A
species is so important to its ecosystem, that when they becomes scarce or extinct, the entire
ecosystem structure can fall. When a
species becomes extinct, a
effect may occur, when
there is a secondary extinction of several organisms as a direct result of the keystone becoming extinct.
species actually build ecosystems around them, such as beavers and elephants. They create
habitats for other community members.