Transcript Ecosystem

Ecology
The study of the relationships
among organisms, and
between organisms and their
environment
 Ecosystem:
A group of organisms
that live in a specific environment,
along with the physical materials in
that environment.
Examples:
 Forest
 Desert
 Marsh
 Pond
 Grassland
Describe an ecosystem that
you are familiar with
 Name
a specific ecosystem
– PNW rainforest
– Puget Sound
– South Puget Prairie
– etc.
 Name
15 to 20 things that you would
expect to find in the ecosystem
– both living and non-living
– be as specific as you can
– provide as much variety as you can
Biodiversity
 Biodiversity:
the variety of different
organisms living in an ecosystem
– Example: Tropical rainforests contain
more species of organisms than any
ecosystem on Earth – they have the
greatest biodiversity.
– Generally, the greater the biodiversity,
the healthier the ecosystem.
David Suzuki: Biodiversity
Video: Introduction to Biodiversity
Jack Longino: entomologist formerly at at
TESC (now at Univ. of Utah); former Griffin
parent
 Edward O. Wilson: ecologist and author


Explain why ants are so important.
What is the smallest animal group on Earth?
How many species?
Biodiversity Explained
 What is the largest group? How many?

Interactions in a Forest Ecosystem
(on a separate page in your notebook)
 Make
a full-page, color drawing that shows the
interactions among animals, plants, and fungi in
a typical northwest forest ecosystem
 Include and label the following in your drawing:
–
–
–
–
–
–
Douglas fir trees
Northern flying squirrels
Mycorrhizae
Truffles
Duff
Magnified drawing of fungi and invertebrates in duff
Douglas Fir
(Pseudotsuga menziesii)
Duff is a layer of dead plant material (leaves,
needles) on the forest floor. It eventually forms soil.
Fungi and small animals live in the duff layer.
Mycorrhizae is an underground fungus
network that attaches to tree roots
The fungus absorbs
water from the soil
and passes it to the
tree
The tree passes
“food” to fungus
Truffles are small “mushrooms,”
produced by mycorrhizae, that contain
spores (“seeds”). Grows in duff.
Northern flying squirrel: eats truffles
from mycorrhizae and spreads the fungus
through it droppings. BBC
BBC Magical Forest 4:05-9:33 & 52:51
Elements of Ecosystems
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Biotic Factors: The living organisms in an
ecosystem
plants, animals, fungi, etc.
Abiotic Factors: The non-living portions of
an ecosystem
 Air, water, rocks, soil, etc.
Habitat: The physical location where an
organism lives. A habitat supplies the
organism with everything it needs to
survive.
Example: habitat of a beaver:



Slow moving
streams and rivers
Ponds and marshes
Must include woody
vegetation (trees,
shrubs)

Community: All the organisms that live in
the same place at the same time and
interact with each other
– A forest community would include trees,
bushes, birds, squirrels, deer, mushrooms. Etc.
Population: All the organisms of the same
species that live in the same place at the
same time
– Examples:
 a population of deer in a forest
 a population of pine trees in a forest
 Limiting
Factor: Any biotic or abiotic
factor that restricts the number of
individuals in a population
– Examples:
 Water
is a limiting factor in a desert
 Sunlight is a limiting factor deep in the ocean
 Other limiting factors:
– Temperature (heat or cold)
– Oxygen
– Disease
– Lack of soil
Interactions in
Ecosystems
How do organisms affect one
another in an ecosystem?
► Predation:
one organism kills and eats
another organism
 Predator: Wolf
Prey: Deer
 Predator: Woodpecker Prey: Beetle larva
► Competition:
organisms compete for the
same resources (food, water, light, mates)
 Foxes and hawks compete for food
 Trees compete for sunlight
 Humans compete with insects for food
Symbiosis
A close relationship between two
different organisms (usually, one
organism lives in or on the other)
Three Kinds of Symbiosis
► 1.
Parasitism: one organism benefits
(parasite), the other is harmed (host)
► 2.
Commensalism: One organism benefits,
the other is neither helped nor harmed
► 3.
Mutualism: Both organisms benefit
(“cooperation”)
Symbiosis
Hidden World of Mites
Miniature World on Skin
Examples of Parasitism
Mistletoe on a tree
(Parasitism)
Ticks and Tapeworms
(Parasitism)
Parasitic Wasps
(Parasitism)
Tree Fungus
(Parasitism)
Athlete’s Foot Fungus
(Parasitism)
Oak Gall Wasp
(Parasitism)
Tongue Louse
(parasitism)
Cordyceps Fungi
attacking insects
Cordyceps Fungi
(from Planet Earth: Jungles)
Examples of Commensalism:
Remoras on a larger animal
(Commensalism)
Barnacles on a Whale
(Commensalism) (or mutualism?)
Clown Fish and Sea Anemone
(Commensalism)
Lichen or moss on a tree
(Commensalism)
Epiphytes on a tree
Examples of Mutualism:
Lichen (algae + fungus)
(Mutualism)
Mycorrhizae (fungus) and tree roots
(Mutualism)
Flower and pollinating insect
(Mutualism)
Wasp and fig tree
(Mutualism)
Cleaner shrimp
(Mutualism)
Beneficial Bacteria in Human Intestine
(Mutualism) (or parasitism?)
Oxpecker and Large Mammal
SciShow: Human Symionts
Assignment: Analyze an Ecosystem
Video: Queen of Trees
Answer the questions on the worksheet
Note that questions are not necessarily in order!
Niches
What good is a snake?
► Every
organism has its own unique “job” in
its ecosystem.
► Niche: The role that an organism plays in
its ecosystem.
► Describing an organism’s niche:




What does it eat?
What eats it?
How do its activities affect other organisms?
How do its activities affect the physical
environment?
Example: Beaver
Niche of a Beaver?
► Beavers
eat shoots, leaves, and bark
Beavers are prey for large carnivores
Beavers cut down trees and shrubs,
build dams, create ponds
Effects of Beaver Ponds:
► Flood
and kill trees
► Encourage growth of shrubs
► Create habitat for pond animals
► Slow the speed of streams – remove
sediment
► Provide resting places for young salmon
► Flood human roads, property
Describe the
niche of:
Orb
Spider
Pocket Gopher
Oak
Tree