Transcript Chapter 4

Chapter 4
Ecosystems & Communities
Section 4-1: The Role of Climate
Key Idea:. All organisms are adapted to live in a
particular climate. This is done through years of
evolution.
What is the difference between weather & climate?
Weather – the day-to-day condition of the
Earth’s atmosphere at a particular time
& place
Climate – the average, year-after-year
conditions of temperature &
precipitation in a particular region
- latitude & topography play a role
Microclimate – conditions vary over small distances.
South side of a rock is warmer than the north
side.
Section 4-1: The Role of Climate
What is the Greenhouse Effect?
1. The atmosphere acts like a blanket
because CO2 (carbon dioxide) , CH4
(methane), H2O vapor, etc. trap heat.
2. This is a completely natural process that
helps keeps the biosphere’s
temperatures suitable for life.
3. If it wasn’t for these gases, the Earth’s
temperatures would be 30o C cooler.
Section 4-1: The Role of Climate
What is the effect of latitude on climate?
Latitudes farther away from the equator
get less sunlight/heat.
Key Idea: This unequal heating of the Earth
creates ocean currents & prevailing wind
patterns, both contribute to climate.
Section 4-1: The Role of Climate
What are the 3 climate zones caused by
latitude?
1. Polar:
A. Farthest from equator
B. Gets the least amount of sun/heat
due to low sun angle
C. 66.5o to 90o latitude
Section 4-1: The Role of Climate
What are the 3 climate zones caused by
latitude?
2. Temperate:
A. Between the tropical & polar zones
B. This zone has changes of seasons
C. This is what we live in
Section 4-1: The Role of Climate
What are the 3 climate zones caused by
latitude?
3. Tropical:
A. Nearest to & includes the equator
B. Sun is mostly directly overhead all year
long & no real change of season.
C. 23.5o N = Tropic of Cancer
23.5o S = Tropic of Capricorn
Section 4-2: Niches & Community
Interactions
Key Idea: Ecosystems are shaped by biotic &
abiotic factors.
Biotic Factors: all of the living things that an
organism can interact with like food chains and
food webs
Abiotic Factors: nonliving things that influence
the interactions among organisms like
climate/weather, soil type, and amount of water.
Key Idea: The biotic & abiotic factors of the area in
which an organism lives is called habitat.
Section 4-2: Niches & Community
Interactions
What is the relationship between habitat &
niche?
Tolerance – the range of environmental
conditions an organism can survive.
Habitat – “address” of the organism
Niche – “job” of the organism
Definition of Niche – full range of physical &
biological conditions in which an organism lives
& the way in which the organism uses those
condition
Section 4-2: Niches & Community
Interactions
Three things you need to know about
niches:
1. The number of niches within an
ecosystem is limited.
2. No two species can occupy the same
niche (a.k.a. – competitive exclusion
principle)
3. Evolution by natural selection determines
which of the species get to occupy the
niche.
Section 4-2: Niches & Community
Interactions
What is the difference between a
fundamental niche & a realized niche?
Fundamental niche – all of the possible
niches that an organism can occupy
Realized niche – the actual niche that the
organism occupies due to competition
Section 4-2: Niches & Community
Interactions
Types of community interactions:
1. Competition – organisms of the same or
different species attempt to use the same
resource (food, shelter, nesting site, etc.)
2. Predation – one organism tries to capture &
eat another organism
Predator: the hunter
Prey: the food organism
* Predation is a key factor in evolution;
cheetahs are fast because their prey is fast
Section 4-2: Niches & Community
Interactions
Types of community interactions:
3. Herbivory – coevolution occurs
between plants & herbivores.
- grasses has evolved to grow
from the bottom up to better
survive getting eaten.
- cactus has evolved spikes to
keep from getting eaten.
Section 4-2: Niches & Community
Interactions
Types of community interactions:
3. Symbiosis – a close, living arrangement between two
different species in which at least one of them benefits.
3 Types of Symbiosis:
1. Mutualism – both species benefit
A. Plants & their pollinators
B. Humans & intestinal bacteria
2. Commensalism – one species benefits & the other is
not affected
A. Barnacles on whales
B. Remoras that attach to sharks
3. Parasitism – one species benefits & the other is
harmed
A. Tapeworms, ticks, fleas, etc.
Section 4-3: Succession
Ecological Succession: predictable changes in a
community over time
3 Types of Succession:
1. Primary Succession – occurs where there was no
soil before (i.e. after a volcanic eruption or bare rock
exposed by a melting glacier)
Pioneer Species – 1st species to populate an area;
often lichens (symbiotic relationship between
an alga & a fungus)
2. Secondary Succession – a disturbance has
destroyed the existing community; occurs after a
forest fire or after farmland has been abandoned. It
should return to the original community known as
the climax community.
3. Marine Succession – occurs when a dead whale
sinks to the deep bottom of the ocean