Chapter 4: Ecosystems and
Communities
4-1 The Role of Climate
Climate
• Climate: long-term,
averages, over entire
biome
• Weather: short-term, local
day to day
• Greenhouse Effect
– It’s a good thing!
– CO2, H2O, CH4 all trap
heat and hold it next to
the surface
– Keeps the temp suitable
for life Solar Energy
The Effect of Latitude on Climate
• Earth has 3 climate zones due to unequal
heating because of the angle of the sun.
Most intense heating is near the equator.
– Polar
– Temperate
– Tropical
Heat Transport
• Ocean and wind
currents help produce
Earth’s climates
• The ocean is a huge
heat sink for the earth.
• Currents and winds
are affected by land
masses and Earth’s
rotation
4-2 Niches and Community
Interactions
The Niche
• Niche – Where and How something lives;
its role
– Habitat is the organism’s address
– Niche is the organism’s occupation
Dendrobates tinctorius
dyeing poison dart frog
An analysis of niche
Poison Dart Frog – discovery
Camouflage
What defines a niche?
• Where it lives
• Humid, wet habitats; on or
close to ground
– (skin is not waxy enough
• What it eats
to prevent dehydration)
– South America
• What eats it
• Tadpoles eat almost anything
• Adults = insectivores; ants
• How it reproduces termites, spiders
• Few predators – poisonous
• Eggs laid on land, male
fertilizes directly over top and
then carry the nearly hatched
tadpoles on his back to water.
What defines a niche…cont…
•
•
•
•
What nutrients it needs
Movement
Range of tolerance
How it interacts with
others/abiota
• Role it plays in energy
flow and nutrient cycling
• Needs natural diet to
create poisons. Toxins
not produced on captive
diets (lack alkaloids)
• Finger & toe tips have
glandular adhesive pads
that enable climbing
• 70-80F, 60% humid, 10hr
light, Cl-free water
• Stands out b/c it’s
poisonous
• Respires through skin,
consumer (omnivore)
COMMUNITY INTERACTIONS
Problem:
2 niches overlap
WHAT IS YOUR SOLUTION?
1. Migrate
2. Change feeding habits
3. Adapt behavior
4. Suffer a sharp population decline
5. Become extinct in that area
What type of species overcome this more easily?
 Generalists
 or Specialists?
Phrased another way:
I want something that you
want…
• Will we compete?
• Will I eat you?
• Will we work together
some how?
Competition
Predation
• In nature, there are 3
basic types of
interactions…
Symbiosis
Community Interactions
1. Competition
•
Organisms compete for
resources
Ex: Food, Mates, Shelter
•
Competitive Exclusion
Principle – no 2 organisms
occupy same niche at same
time.
2. Predation
•
One organism (predator)
captures and feeds on another
(prey).
Community Interactions
3. Symbiosis
•
Mutualism – both benefit
Ex: Flowers & insects
Egrets & Alligators
Clown Fish & Sea Anemone
•
Commensalism – one
benefits, the other is not
helped or harmed
Ex: Barnacle & Whale
•
Parasitism – one benefits,
other is harmed
Ex: tapeworms, fleas, ticks,
lice
Community Interactions
3. Symbiosis
•
Mutualism – both benefit
Ex: Tapeworm
• Commensalism – one
benefits, the other is not
helped or harmed
Ex:
• Parasitism – one benefits,
other is harmed
Ex: tapeworms, fleas, ticks,
lice
Species Interactions
Examples of Symbiosis
Specialty Niches
Invasive vs. Native Species
Indicator Species
Keystone Species
Invasive Species
Carcinus maenus, the European Green Crab, was
introduced to North America in the 1800's. This predator
now ranges from Nova Scotia to Delaware.
Purple
loosestrife
& Kudzu
3 examples:
Macquarie Island / Pythons/Asian Carp
• http://www.youtube.com/watch?v=QOxoZ
B6PxpU&playnext=1&list=PLB127E4EA4
4F5FC28
• http://www.youtube.com/watch?v=PjaM7w
BWWoc&feature=relmfu
• http://www.youtube.com/watch?v=mUssO6
8D2eM (to 6:30)
Native Species
Indicator Species
Keystone Species
Kelp forest
Sea Otter
Dung Beetle
Foundation Species
Biosphere
Biosphere
Ecosystems
4.3 ECOLOGICAL
SUCCESSION
Communities
Populations
Organisms
What is succession?
TIME
Is Disturbance a Good Thing?
• Life is always changing
and then responding to that change.
• Plant (& therefore animal) species are
constantly being replaced with more complex
species
• This is called ecological succession
Arrange the pics in the correct
order…
Ecological Succession
• Primary OR Secondary Succession?
• Depends on starting conditions:
– Is there any soil present?
– Does not matter if life had been there
previously or not
PRIMARY SUCCESSION
– Lifeless beginnings
– Starts WITHOUT SOIL.
• Examples:
– Bare rock exposed by glaciers or severe erosion
– Newly cooled lava
– Abandoned highway or parking lot
– Newly created shallow reservoir
PRIMARY
• Life begins with
PIONEER SPECIES
• Hardy, small
• Population grows quickly
• Grow close to the ground
• Ex: bacteria, moss, lichens
SUCCESSION
SECONDARY SUCCESSION
• Starts WITH SOIL.
• start from roots or seeds remaining or seeds carried in
by wind or animals
• Examples:
– Abandoned farms
– Heavily polluted streams
– Ponds from dams or flooding
Succession of Plants
• Pioneer species make an area suitable for more
plants
– A process called “facilitation”
• Early successional species
– Can withstand little nutrient availability
– A little taller than pioneers: small herbs, grass
Plant succession continued
• Mid-successional species
– Need more fertile soil w/ moisture
– Must wait for some decomposition
– Tall grass & low shrubs, eventually sun-loving
trees
• Late-successional species
– Need deep, fertile, moist soil
– Slow growth rate
– shade tolerant trees
Climax Community
• Succession is unpredictable
• While it generally proceeds from small to tall,
each disturbance is unique and each pioneer is
unique…leading to unique community
developments
• The most mature community is called the
climax community
/
Disturbances can lead to
opportunity for others
• Hurricanes…
• In S. Fla. the Everglades
depend upon the periodic
hurricanes for the continued
existence of the mangrove.
– Why?
• Primary or secondary?
• Importance of Mangroves
POND SUCCESSION
PUT IN ORDER OF SUCCESSION
M&M’s Weather vs. Climate
•
•
•
•
•
•
Red = Warm and Sunny
Yellow = Warm and cloudy
Green = Cool with light rain
Blue = Cold with steady rain
Orange = Hot, sunny
Brown = Hot very humid and sunny