Part 1:
Ecosystems: Everything Is
Connected
Chapter 7: Aquatic Ecosystems.
Environmental Science and the Earth
Ecosystems: Everything Is Connected
• Example of the idea that
“everything is connected”
• In 1995, scientists
interested in controlling
gypsy moths, which kill
oak trees, performed an
experiment.
Photo by R. Jowsey
Everything Is Connected: Example
http://news.nationalgeographic.com/news/bigphotos/image
s/071022-vibrating-mice_big.jpg
• The scientists removed
most mice, which eat
young gypsy moths,
from selected plots of
oak forest.
• The number of young
gypsy moth eggs and
young increased
dramatically.
Everything Is Connected: Example
• The scientists then added
acorns to the plots.
• Mice eat acorns, therefore the
number of mice soon
increased, and…
• The number of gypsy moths
declined as the mice ate them
as well.
http://cakboliv.files.wordpress.com/2009/08/a
corns_nut_mc_.jpg
Everything Is Connected: Example
• This result showed that
large acorn crops can
suppress gypsy moth
outbreaks.
http://images.suite101.com/608399_com_img_9740.jpg
Everything Is Connected: Example
Photo by R. Jowsey
• Oh but there is
more!!!
• Interestingly, the
acorns also
attracted deer,
which carried ticks.
• Young ticks soon
infested the mice.
http://www.deerticks.com/content/modules/rhino.pages/files/uploads/deer/deerticks/img-002.jpg
Everything Is Connected: Example
• Wild mice carry the
organism that causes
Lyme disease.
• Ticks can pick up the
organism when they
bite mice.
• Then the ticks can bite
and infect humans.
http://ladydamorea.files.wordpress.com/2012/06/deertickbullsey
e.jpg
Everything Is Connected: Example
• This example shows
that in nature,
things that we
would never think
were connected—
mice, acorns, ticks,
and humans—can
be linked to each
other in a complex
web
http://www.thefastertimes.com/globalpandemics/files/2010/01/borreliaburgdoferi-life-cycle.gif
Defining an Ecosystem
• The mice, deer, moths, oak trees, and ticks in
the previous example are all part of the same
ecosystem.
• An ecosystem is all of the organisms (biotic)
living in an area together with their physical
(abiotic) environment.
Defining an Ecosystem
• Ecosystems can be large
like an oak forest or coral
reef, or they can be small
like the vacant lot next
door to your home.
http://www.biology-blog.com/images/blogs/122006/oak-forest-5720.jpg
• The Natick
projects.
http://www.nexuslearning.net/books/Holt_Env_Science/4-1.pdf
Defining an Ecosystem
• Just like living things are connected, so to are
ecosystems.
• Things move from one ecosystem into
another.
• Soil washes from a mountain into a lake, birds
migrate from Michigan to Mexico, and pollen
blows from a forest into a field.
The Components of an Ecosystem
• In order to survive, ecosystems need at least
five basic components:
1. A source of energy
2. Mineral nutrients
3. Water
4. Oxygen
5. Living organisms
Photo by R. Jowsey
Biotic and Abiotic Factors
• An ecosystem is made up of both living and
nonliving things.
• Biotic factors are the living and once living
parts of an ecosystem, including all of the
plants and animals.
• The biotic parts of an ecosystem interact with
each other in various ways (food webs,
symbiosis, etc).
Biotic and Abiotic Factors
• While living things interact with each other in
an ecosystem, they also interact with the nonliving factors in an ecosystem.
• The non-living components of an ecosystem
are known as abiotic factors.
Biotic and Abiotic Factors
• Identify three biotic and
three abiotic factors that
are in the cold northern
ecosystem of Denali
National Park in Alaska
(shown in photo).
http://www.nexuslearning.net/books/Holt_Env_Science/4-1.pdf
Biotic Factors
1.
2.
3.
Abiotic Factors
1.
2.
3.
Organisms
• An organism is an
individual living thing.
• You are an organism, as
is an ant crawling across
the floor, an ivy plant
on the windowsill, and
a bacterium in your
intestines.
• Organisms are classified
into 4 major groups:
Bacteria, Plants,
Protists, and Animals.
Period 1 Organism
Peter Creed
Species
• A species is a group of organisms that are closely related.
• In order for two organisms to be classified into the same
species, they must meet thesefour criteria.
• The two organisms must able to:
•
•
•
•
Successfully mate
in a Natural Environment (not a lab or zoo, etc.)
and produce viable offspring (healthy, able to survive to adulthood)
and those offspring are fertile (can reproduce).
• All humans, for example, are members of the species group
sapiens and the genus group Homo. This produces the
scientific name for humans; Homo sapien.
Species
http://i.cdn.turner.com/cnn/2010/US/09/23/what.is.zedonk/story.ze
donk.carr.jpg
• The photo shows a
zedonk.
• A zedonk is a cross
between a zebra and a
donkey.
• The zedonk is a sterile
animal and cannot
reproduce. Therefore, a
zebra and a donkey are
NOT the same species.
Species
• Zebras and donkeys can successfully mate, in a
natural environment and produce viable
offspring.
• Are zebras and donkeys therefore members of
the same species? Why or why not?
http://www.greatplay.net/i
mages/zebra.jpg
http://upload.wikimedia.org/
wikipedia/commons/thumb/7
/7b/Donkey_1_arp_750px.jpg
/250pxDonkey_1_arp_750px.jpg
http://i.cdn.turner.com/cnn/2010/US/09/2
3/what.is.zedonk/story.zedonk.carr.jpg
Populations
• A population is all the members of the same
species that live in the same place at the same
time.
• An important characteristic of a population is that
its members usually breed with one another
rather than with members of other populations.
• Populations have really cool names: pod of
bottlenose dolphins, gaggle of Canadian geese,
murder of crows, smath of jellyfish.
•
http://en.wikipedia.org/wiki/List_of_animal_names
Populations
http://www.nexuslearning.net/books/Holt_Env_Science/4-1.pdf
• The Bison will usually
mate with another
member of the same
herd, just as the
wildflowers will
usually be pollinated
by other flowers in
the same field.
Communities
• An organism does not live alone and neither
does a population.
• A community is a group of various species
that live in the same place and interact with
each other.
Communities
Photo by R. Jowsey
• A pond community, for
example, includes all
of the populations of
plants, fish, and insects
that live in and around
the pond.
• All of the living things
in an ecosystem are
members of the same
community.
Communities
• The most obvious difference between
communities is the types of species they have.
• Land communities are often dominated by a
few species of plants. In turn, these plants
determine what other organisms live in that
community.
Communities
• For example, the most
obvious feature of a
Colorado forest might be
its ponderosa pine trees.
• This pine community will
have animals, such as
squirrels, that live in and
feed on these trees.
http://www.sprucepointtreefarm.com/images
/spruce.jpg
http://shelledy.mesa.k12.co.us/staff/comp
uterlab/images/CO_Mammals_Pine_squirr
el.jpg
Habitat
• The squirrel discussed
above lives in a pine
forest. The pine forest is
the squirrel’s habitat.
• A habitat is where an
organism lives.
• The habitat of the
salamander in this photo
is a damp forest floor.
http://www.nexuslearning.net/books/Holt_Env_Scien
ce/4-1.pdf
Habitat
http://www.coralreefinfo.com/images/coral_reef.jpg
• Every habitat has specific
characteristics that the
organisms that live there
need to survive.
• A coral reef contains sea
water, coral, sunlight, and
a wide variety of other
organisms.
• If any of these factors
change, then the habitat
changes because
everything is connected.
Niche
• An organism’s niche is the
role it plays in an
ecosystem.
• Often describes where an
organism “fits” in a food
chain.
• Example: A woodpecker’s
niche is eating insects