Transcript ECOLOGY

ECOLOGY
Ecology
• Ecology is the scientific study of interactions
between organisms and their environments
• Organization of the Biosphere:
– Organisms (of the same species make a…)
– Population (interacting together make a …)
– Community (interacting with abiotic factors makes an
…)
– Ecosystem (all of the ecosystems around the world
make up the …)
– Biosphere
Primary Succession of plants
in an environment
1.
First in the environment are the pioneer
organisms. These create the initial layer of
nutrients (soil) and break up rocks.
2. Next new plants come in, but amount of
nutrients determines the types of species. The
successful species will be those best adapted
with the right “range of tolerance”.
3. Every generation of plants will create more soil
due to decomposition
4. Competition between plants finally leads to
climax community.
Primary Succession in our Ecosystem
Secondary Succession
• Secondary succession is the development of new
inhabitants to replace the previous community
of plants and animals that has been disrupted or
disturbed by an event (e.g. forest fire, flood,
harvesting, epidemic disease, pest attack, etc.).
Secondary Succession
Biogeochemical cycles
The Water Cycle:
Steps:
• 1. water evaporates from bodies of water or directly from the
leaves of plants (called transpiration)
• 2. condenses in atmosphere to form clouds
• 3. precipitation occurs
• 4. runs off into bodies of water or is absorbed by plants
from runoff (when water runs along the ground) or
groundwater (when water sinks into the ground)
The Carbon Cycle:
• Steps:
• 1. CO2 from atmosphere is absorbed by plants
Carbon Cycle
• 4 Ways of returning carbon to atmosphere:
• 1. Plants give it back off during respiration
• 2. Animals (that directly or indirectly
consumed the plants) return it during
respiration
• 3. Plants and animals die and decompose to
return carbon gases to atmosphere
• 4. Decomposition may result into fossil
fuels. When burned, carbon also returns to
atmosphere in the smoke.
The Nitrogen Cycle:
• Steps:
• 1. Nitrogen gas from atmosphere absorbed by
nitrogen-fixating bacteria (found in nodules on
roots of legumes/special plants)
• 2. The bacteria convert N to ammonia
• 3. Ammonia is absorbed by plants, which are eaten
by animals.
• 4. Ammonia passed down the food chain
• 5. Ammonia is returned when animals die
(decomposition) and is either reabsorbed by plants
or returned back to atmospheric nitrogen by
different soil bacteria by being denitrified.
What are Biomes?
Biomes are regions in the world that share similar
plant structures, plant spacing, animals, climate
and weather.
Tundra
• Very cold
• Low diversity (few varieties of organisms)
• Simple vegetation (no trees and short growing
season)
• Permafrost – soil below a certain point never
thaws
Grasslands
These are areas covered by grass with very few trees.
There are two types of grasslands. The tropical
grasslands (savannah) has a wet and dry season and the
temperate grasslands have a hot summer and cold
winter.
Desert
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Very little vegetation
Very few animals
Very little rain
Extreme temperature variations (100+ during
the day and 40 at night.)
Tropical Forest
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Very rainy and warm
Little variation in climate (no seasons)
Highly diverse species (Lots of organisms)
Soil is nutrient-poor and acidic b/c of rain
Decidious Forest
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Lots of plants
Trees with broad leaves
Soil is rich with organic matter
Even precipitation throughout the year
Coniferous Forest
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Also called the taiga or boreal forest
The largest terrestrial biome
Temperatures are low
Precipitation is primarily snow
Soil is nutrient poor and acidic
Trees are mostly conifers
Animals include woodpeckers, hawks, moose, bear and lynx.
Marine Biome
• Consists of oceans, coral reefs, and estuaries
• The ocean is the largest of all ecosystems.
• The ocean contains a diverse array of plants and
animals at various depth zones.
• Coral reefs consist mainly of coral.
• Estuaries are areas where fresh and salt water
environments converge. They are biologically diverse,
which means they have many different species
Freshwater Biomes
• Includes ponds, and lakes; streams and rivers, and
wetlands.
• Ponds have stagnant water which means it has no
current or flow
• Streams and rivers move in one direction.
• Wetlands are areas of standing water that support
aquatic plants.
Other Vocab
• Range of Tolerance: range of abiotic factors of an
environment that a species can tolerate (stand) to
stay alive.
• Limiting factors: factor that restricts the existence,
numbers, reproduction, or distribution of
organisms
• Niche: Role or job an organism has in its
environment. Limits competition.
• Symbiotic relationships: relationship between 2
organisms.
– Symbiosis = “living together”. There are 3…
Mutualism – both benefit, neither is
harmed
Commensalisms – one benefits, the
other doesn’t, but is not harmed
Parasitism – one benefits, the other
(host) is harmed and can die
Energy in Ecosystems
• Autotrophs vs. Heterotrophs:
– Autotrophs can utilize light energy (photosynthesis) or
inorganic chemicals (chemosynthesis) to produce their
own chemical energy (sugars).
– Heterotrophs must consume some other organism to get
that chemical energy.
• Food Chain: Shows one possibility of energy
transfer in an ecosystem. Each feeding step =
trophic level.
• Food Web: shows many possibilities of energy
transfer in an ecosystem (since many organisms
eat more then one type of food).
• Food/Energy
Pyramid: Shows
amount of
energy available
at each trophic
level. This can
be shown as
calories, or
biomass.
• Biomass: all
individuals and
their parts of a
species in an
ecosystem. More
biomass at low
trophic levels
than at high
trophic levels.
Population Dynamics
• Populations are not stagnant (do not stay the
same)
• Follow exponential growth at the beginning
• Continue to grow until Carrying capacity of env.
is reached (resources start to run out)
• Growth levels out and becomes logistic
> Limiting factors kick in
> Pop decreases back to the carrying capacity