Transcript Primary Succession

Communities, Biomes and
Ecosystems
with Population Dynamics
Chapters 3 & 4.1
Communities
• Limiting Factor: biotic or abiotic factor that
restricts the members, reproduction, or
distribution of an organism
Most species have a range of tolerance for these
factors – this plots like a bell-shaped curve
Ecological Succession
the changes in a community that occur over time
• occurs when a new land area is exposed
or when an existing land area is disturbed
Primary Succession
occurs on new land areas or where no soil exists –
volcanic islands, bare rock, glacier melting,…
Pioneer Species –
the first species to inhabit an area
Secondary Succession
occurs when an existing community had been disturbed and
regrowth occurs
Succession usually culminates in a climax community.
Climax Community….
•a stable community – (the living things in a given area)
•is the end results of succession
•the final community to inhabit an area
Climax Community
Desert
Baja, California
Latitude effects climate
• Latitude = the distance of any point on Earth
from the equator.
• Climate is directly affected by receiving
unequal solar radiation
CLIMATE
the average year to year
conditions of temperature
and precipitation in a
particular region
What is our climate?
What is Alaska’s climate?
WEATHER
the day to day conditions of
Earth’s atmosphere at a
particular time and place
What is our weather today?
What about Thanksgiving
Day?
Greenhouse Effect
occurs when heat is retained by the atmosphere
• carbon dioxide, methane, water vapor and other gases in the atmosphere
trap heat energy
• the atmosphere acts like an insulating blanket around the planet
• Can cause
climate changes
In summary…
Latitude  climate
Climate  weather
Weather  precipitation
Precipitation  flora (vegetation)
Flora  fauna (animal life)
Do you see the relationship?
BIOME
large geographical area having…
• characteristic temperature range and precipitation
• characteristic plants and animals
• LAND = terrestrial; WATER = aquatic
Terrestrial:
TUNDRA
TAIGA (BOREAL FOREST, CONIFEROUS FOREST)
TEMPERATE (DECIDUOUS) FOREST
GRASSLAND
temperate = prairie
tropical = savanna
DESERT
TROPICAL RAIN FOREST
Aquatic:
MARINE
FRESH
Tundra
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Cold & largely treeless
Covers 1/5 of world’s land
Little precipitation (mostly frozen)
Flora: Small, slow growing plants (grass, moss, sedge)
Fauna: caribou, arctic fox, snowy owl, musk oxen
Permafrost: permanently frozen layer of soil under
surface
• Summer can cause boggy ponds & different fauna
Taiga (Boreal, Coniferous)
• South of tundra
• Flora: cone-bearing, evergreen trees (pines,
hemlocks, spruces, junipers, firs)
• Fauna: moose, grizzly bear, wolf
Temperate (deciduous) forest
• Trees that lose leaves found here
• Warmer winter, longer summers
• Flora: birch, oak, maple, beech, dogwood, &
some evergreens
• Fauna: fox, squirrel, WT deer, raccoon, black
bear, coyote
*You live here
Temperate Grassland
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Also known as prairies (“the bread basket”)
Dominated by grasses
Less rainfall, so not too many tall trees
Rich, fertile soil
Flora: corn, wheat, potatoes, many other cereal
grains
• Fauna: grazing animals (bison, other livestock)
Tropical Grassland
• Also called savannas
• Can be in tropical or subtropical regions
• Flora: Mainly grasslands with scattered trees
& shrubs
• Fauna: lots of herbivores (zebra, giraffe,
gazelle) as well as carnivores (lions, leopards,
cheetahs)
Desert
• Less than 25 cm rainfall per year
• Can be cold as humidity is low
• Sparse vegetation that have adaptations for
conditions
– Waxy coating, water storage, transpire @ night,
thorns on exterior for protection
• Flora: cacti, Joshua trees
• Fauna: kit foxes, snakes, lizards, road runners
Tropical Rainforest
• Most productive biome
• 1/5 of world’s known species live here (LOTS
of insects)
• Canopy: formed from a continuous layer of
treetops that shades the forest floor
• Fauna: sloth, birds, monkeys, beetles
Aquatic/Water Ecosystems
are determined by water chemistry (pH, salinity, dissolved
oxygen,…) depth, flow and temperature
Aquatic Ecosystems
• Marine
– 97.5% of water on Earth
• oceans
• Freshwater
– 2.5% of water on Earth
• Almost 69% in glaciers
• Roughly 30% in groundwater
• Less than 0.5% in rivers, streams, lakes, ponds, etc.
*There are transitional aquatic ecosystems where marine
and fresh merge  wetlands, estuaries
Estuary - wetlands formed where rivers
(fresh water) meet salt water
• Affected by the
rise and fall of
tides
• Are usually
shallow
• Spawning and
nursery grounds
for many aquatic
species
Marine Ecosystems
1. Intertidal zone: periodic exposure to air (clams, oysters)
2. Coastal ocean and coral reefs
3. Open ocean zone:
pelagic zone– photic (light) and aphotic (no light)
benthic zone-ocean bottom
abyssal zone-deepest zone
What types of organisms
do you think would live in
each zone?
Freshwater Ecosystem
water having a low salt concentration
(usually less than 1%)
Flowing Water – stream, river, creek
Standing Water – lake, pond
Lake/Pond zones
• Littoral zone: shallow; sunlight can reach
bottom
• Limnetic zone: open water; well-lit; tons of
plankton found here
• Profundal zone: deepest area; colder and less
oxygen
NOTE: not every lake will have limnetic and
profundal zones
population density
number of individuals in a given area
populations will naturally space themselves = dispersion
Factors that may affect population
density
• Density independent: factor that does not
depend on number of organisms; usually
abiotic; ex. Weather event
• Density dependent: factor that does depend
on number of organisms; often biotic; ex.
predation, competition, parasitism, etc.
Remember these interactions?
More population density factors…
• Immigration – movement of individuals
into an area
• Emigration – movement of individuals
out of an area
Carrying Capacity – number of individuals
that can be supported by a given area
Human population growth is
causing…
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severe overcrowding in areas
An increase in energy demands
A need for increased food supply and waste disposal
very rapid ecological change (habitat destruction,
overhunting, introduction of diseases)
* The population tripled from 1930-2000 and is
expected to double again from 2000-2050