Download Chapter 4 Section 2

Organisms Interactions
Chapter 4 Section 2
er
th
o
ch
ea
st
in
a
g
a
or
.
...
er
th
ge
to
k
H o w we a ll wor
Organism Interaction
Coevolution – back and forth evolutionary
adjustments between interacting members of an
ecosystem.
Predators and prey coevolve
predation is the act of one organism feeding
on another.
Other forms of coevolution
Parasitism is when one
organism feeds on and
usually lives on or in another
organism.
Parasites do not usually
kill their prey (host)
because they depend on it
for food and a place to live.
Other relationships
Symbiosis – two or more species live together in a
close, long-term association. They can be
beneficial, harmful, or neutral. (we already
mentioned parasitism or (+,-)
Mutualism – symbiotic relationship in which both
participating species benefit (+,+)
Commensalism – symbiotic relationship in which
one species benefits and the other is neither
harmed nor helped (+,0)
Competition is a force in Nature
When two species use the same
resource, they participate in a
biological interaction called
competition. These resources
include food, water, space.
The functional role of a particular
species in an ecosystem is called
its niche. A niche is how an
organism live, the “job” it
performs within the ecosystem.
Types of Niches
The entire range of conditions an organism is
potentially able to occupy within an ecosystem is its
fundamental niche.
The part of its fundamental niche that a species
occupies is called its realized niche.
If two species are competing, the species that uses
the resource more efficiently will eventually
eliminate the other. This elimination of a competing
species is referred to as competitive exclusion.
Succession: Ch. 4 Sec.3
• The first organism to live in a new habitat are
small, fast-growing plants, called pioneer
species.
• Ecological Succession - series of changes that
occur in a community over time
• Primary Succession - new place becoming
populated with species
• Secondary Succession - species coming back
after a disturbance (soil is already healthy)
Biomes
Chapter 4 Section 4
What affects the Biomes
A major biological community that occurs
over a large area of land is called a biome.
Temperature – most organisms are adapted to
live within a particular range of temperatures
and will not thrive if temperatures are colder or
warmer.
Moisture – all organisms require water. On
land, water is sometimes scarce, so patterns of
rainfall often determine an area’s life-forms.
Taiga
Rainforest
Savanna
8 Biomes
Aquatic Biome
Marine
Largest % of Biomass
(mostly microscopic)
Estuary (marshes)
recycle nutrients
Freshwater (lakes)
Desert
Fewer than 25 cm. of
rain. Drastic
temperature changes
Vegetation is
characteristically
sparse.
(Lizards, snakes,
cacti)
Tundra
Open (no trees),
sometimes boggy biome.
Water is usually
unavailable because it’s
frozen.
15-25 cm of precipitation
(foxes, lemmings, caribou)
Temperate Grasslands
Often highly
productive when
converted to farmland.
Also called prairie.
25-75 cm of rain
(bison, ground hogs,
etc.)
Savannas
Dry climates with
development of
grassland. Open
landscape with
widely spaced
trees.
50-130 cm of rain
(Lions, zebra, etc.)
Taiga
Coniferous forests,
with long, cold winters
40-100 cm of
precipitation
(moose, elk)
Temperate Forests
Relatively mild climates
and plentiful rain promote
forests. Warm summers,
cold winters with rain well
distributed throughout
the year.
70-150 cm of rain per year
(deer, bear, mice, rabbits
etc.)
Tropical Rainforest
Rainfall is 200-600 cm. per
year.
25 degrees C (77 degrees F)
Richest biome in terms of
number of species (more
than 2 million)