Transcript Gorgonopsid in Permian Desert

We’ve already learned through example and models why
biodiversity is important. Let’s define the various types of
biodiversity, however, since there are many:
• Species Diversity
The most commonly thought of biodiversity, and that is
simply defined as the species “richness” or the variety of
species in an area.
This refers to the variety of defined ecosystems within an
• Ecosystem diversity area, such as deserts, grasslands, forests, and such. It
also refers to the number of communities and populations
in an area as well.
• Functional diversity Refers to the variety of processes such as matter and
energy cycling that is accomplished in ecosystems on
Earth. (including nutrient cycles and food webs)
Refers to the variety of genes within a species, which dictate
• Genetic diversity
the characteristics of the organisms that possess them…and
Refers to the variety of human cultures, and attributes of
human cultures which help humans adapt to changing
• Cultural diversity conditions.
• Supplies us with food, wood, fibers, medicines, and energy
• Preserving the quality of our water and air
• Maintaining the fertility of the soils
• Disposal of wastes
• Control populations of pests
There are few things in science that are as controversial as
the origins of life, but the fact is that however it started, it
has persisted on Earth for nearly 3.8 billion years!
As scientists speculate that the first life on Earth was
Prokaryotic…just how did such diversification occur?
The work done in the 1800s by Charles Darwin, and Alfred Wallace helped
to explain how this all happened. • There is a struggle for existence
(competition for resources) in populations
that contain many variations.
• Those that outcompete others in a
population, survive and pass those traits
that helped them, along to their offspring
• Those that compete unsuccessfully, die
and don’t pass their traits along.
Current Stromatolites
Fossil
Stromatolites
Complex
Multicellular Heterotrophs
• Over time, advantageous traits are
selected for naturally…
which is why we call this process… Natural
So far scientists have documented about 1.8 million species of
organisms on Earth.
Predictions indicate that there may be as few as 4
million, to 100 million species in total on Earth, so we are far
from through classifying!
The Six Kingdoms of Life:
Archaebacteria: Only a couple hundred species
Eubacteria: Approximately 10,000 classified Every year,
thousands
Protista: Approximately 270,000 classified
of new
species are
Fungi: Approximately 50,000 classified
identified.
Plantae: Approximately 250,000 classified
Animalia: Approximately 1,150,000 classified
Stromatolites: A record of the oldest life on Earth…
Most of what we know about prehistoric life comes from
fossilized evidence of its existence. Fossils are mineralized or
petrified replicas of skeletons, bones, teeth, shells, leaves,
seeds…or even impressions left by such items and preserved in
rock.
The fossil record
is incomplete.
Why?
Fossil Stromatolites
Teleoceras: Fossilized Rhino
Some animals don’t
leave fossils
behind. Still
others have been
destroyed by the
rock cycle.
The work of piecing together evidence of past life from fossils is done by
the Paleontologist
How do species evolve?
environment in which an organism lives
• Natural Selection The
determines what traits or variations are favorable
• Genetic Drift
Slight random changes in the genetic makeup of a
population over time
This genetic variability is created by chance mutations in
genes of organisms, while DNA is replicating.
Some of these “errors” can occur when
the cells are exposed to agents that cause
mutations…called “mutagens”….such as UV
radiation.
While mutations can occur in any cell
in the body (somatic), it is the
mutations that occur in the sex cells
that enable those mutations to be
passed on to the next generation.
I hope
this
molecule
looks
familiar!
What characteristics have allowed humans to dominate Earth
the way they have?
 Opposable Thumb
 Walking Upright
 Complex Brain
While humans are not by any
means excluded from the
chances of extinction, our
brains may indeed be our most
advantageous adaptation…to
help us find ways to cope with
the changes in the
environment (which we are
largely causing) that most
organisms would find
intolerable, and impossible to
adapt to.
Will humans be able to adapt to future environmental
probabilities? Probably because…
 Nature will only select advantageous traits that already
exist in a population, or that are likely to be created by
mutations.
 Even if that trait is present, reproductive capacity may
hold back the evolutionary tendency
Organisms with very
short life cycles are
far more capable of
producing the
variations necessary
for rapid evolution,
as opposed to those
who only produce 1-4
offspring during
their lifetimes
The Earth today looks nothing like
it did when it formed, and it
continues to change dramatically
every day.
Earth’s molten mantle, which
lies beneath the crust, is
constantly moving the
hardened plates around
through convection currents.
This becomes important as to the
placement of organisms, because where
oceans and land are located greatly
influences environmental conditions.
When these plates carrying the continents separate and/or fuse together, new
environmental conditions arise, setting up new circumstances for organisms. This
gives them the opportunity to adapt, migrate, or become extinct. 
Throughout Earth’s Geologic History, the environment has
changed greatly.
• Hot and dry at the end of the Permian
• Snowball Earth (Proterozoic Eon)
• High oxygen
• High CO2
• Meteorite
impacts
A high degree of
genetic biodiversity
allowed life to
continue on this
planet that is
constantly changing!
Gorgonopsid in Permian Desert
When natural selection leads to an entirely new species, a
process called “speciation” has occurred. Speciation can occur
in a number of ways:
 A species may become Geographically Isolated
Any time a population of
organisms becomes
“isolated” they have the
chance to “diverge”
from the other
population.
Places on Earth that have
been “isolated” for long
periods of time, have
developed really diverse and
“weird” species.
 A Species is Reproductively Isolated
Occurs when something acts to prevent
organisms from reproducing together
A natural process which affects the levels of biodiversity on
Earth is extinction. Extinction occurs when the last surviving
individual of a species is gone.
Determining the exact moment of extinction is difficult, and is
often determined retrospectively. Sometimes the
reproductive potential of a species ceases before the last
individual actually dies.
Every day about 137 species
Coqui
become extinct. That’s over
50,000 species every year!
The most vulnerable species
are “endemics”, who are only
found in one area.
• Amphibians
Blue Poison Dart Frog of Surinam
Takahe in New Zealand
Panamanian golden frog
The fossil record indicates that a low rate extinction (or
background extinction) occurs when one to five species
becomes extinct for each million or so species on
Earth…whereas a Mass Extinction occurs when there is a
significant rise above background level.
Mass extinctions occur when
global catastrophic events
cause large groups of species
(25-70%) to be wiped out, in
a geological period lasting up
to 5 million years.
Mass extinction periods also
are marked by low speciation
rates as well.
The one plus that occurs during periods of mass extinction is that it gives new
species the opportunity to fill the habitats and niches left by the now extinct
organisms.
Each species in an ecosystem
plays a role, also known as an
“ecological niche”. A niche can be anything from dietary needs
of organisms, temperature needs, or
Niche is not to be
amount of daylight, or darkness that they
confused with
need. A niche may also include mating and
habitat, which is
reproductive patterns
where an organism
lives.
Niches are
used to help
define species
as either
“generalists” or
“specialists”.
Roaches, the great generalists
The narrower the niche, the more prone to extinction a species is.
Native species are those which are Indicator species are those which are
indigenous, or that normally live in used as a “gauge” by ecologists to
an ecosystem.
determine the health, or degree of
ecological danger in an ecosystem.
Giant Swallowtail Butterfly
American Elm in Fort Worth
Lichens
Tree of Heaven
Nonnatives are also known as
invasive, or exotic species
North American Bison
Remove the keystone, and the arch tumbles
Black-Tailed Prairie Dogs
Just as keystones are
the most important
factor that hold arches
together, keystone
species have a great
affect on the types and
abundance of other
species in an ecosystem.
Many keystone species
are prone to extinction
because of small
populations, which leads
to a cascade effect.
Foundation species
actually “build”
Bald and golden eagles, swift foxes, coyotes,
ferruginous hawks, burrowing owls, badgers
ecosystems, literally
and black-footed ferrets, countless insects
providing the
and other invertebrates, as well as plants also
“foundation” for the
rely on Prairie Dogs and their activities.
community.
Each of you will produce a three-slide PowerPoint presentation…to be added to a
“class presentation”. Each person’s presentation must have imported
graphics/pictures/animation, and:
Slide One:
Highlight one species that has become extinct on Earth (with picture)
 When?
Why…what were the circumstances?
What niche did they fill in their ecosystem?
What was their habitat like?
Were they keystone species, or foundation? Etc…
Slide Two:
Tell how the extinction of that species impacted/affected/ caused a cascade
effect in their ecosystem, or impacted at least two other organisms
 Slide Three:
Choose an endangered species, and predict what would happen in their
ecosystem if they were to become extinct.