Transcript Ecology The study of ecosystems

Ecology
The study of ecosystems
Environments
• Almost anywhere/everywhere is an
environment to at least some sort of
organism.
• Ie: urban, rainforest, polar, grasslands,
mountains, oceans, freshwater lakes,
deserts, everglades, rivers/streams,
your body, etc…
Human Microbiome
Ecosystems
• Every living organism on earth lives in an
ecosystem
– The living and nonliving things in one place.
• Non-living factors vs living factors
– Abiotic vs biotic
– Abiotic factors are the nonliving parts of an
ecosystem.
• The types and amounts of abiotic factors determine the
organisms that live there
5 important abiotic factors
• Water
– All organisms need water to survive. Some need more than others.
• Light
– Plant life obviously needs light to photosynthesize.
• Temperature
– Generally, more sunlight means warmer temperatures.
• Atmosphere
– An atmosphere is a mix of gases surrounding a planet. What gases
surround our planet? (next slide)
• Soil
– Contains different amounts of nutrients, minerals and rock.
• Remember why venus fly trap needs to eat flies?
– They grow in nutrient poor soil
Jaws of death
0.93%
0.034%
21%
78%
A climate
minute
Global warming
Hank Green
Biotic Factors
• “All of the living or once-living things in an
ecosystem.”
They are categorized into the following:
– Communities are the living parts of an ecosystem
that live and interact with each other.
– Populations• Group of organisms of the same species that live
together.
– Biomes- geographic area on earth that contains
ecosystems with similar biotic and abiotic
features.
Name some different ecosystems found
within the ecosystem (not in notes)
Community (not in notes)
Populations (not in notes)
Factors that affect health of
populations
• Population size
– Can increase or decrease depending on lots of
different circumstances. Like what?
• Population density
– This describes the number of organisms in the
population relative to the amount of space
available.
– Lets figure out the population density of our
classroom. How many cubic feet does each of us
have?
Limiting factors
• Limiting factors are factors that can limit the
growth of a population.
– Lets think of some:
•
•
•
•
•
•
•
Available water
Space
Shelter
Food
Predation
Competition
disease
Carrying capacity of an ecosystem
• Many times populations will reach their
carrying capacity.
– Largest number of individuals of one species that
an ecosystem can support over time.
Food chain/food web
GMO
mosquitos
• All living and nonliving things in an
ecosystem are interconnected
• Think of an environment as a spider web.
– When one thread is disturbed, the entire web is
disturbed.
– If a thread is cut, the web might still work but is
weakened.
Keystone species
•
Species that plays a crucial role in an ecosystem. Without it,
the ecosystem could change dramatically.
• Examples:
– Beavers: Beavers are considered habitat engineers because they
change the environment by building dams. This dam building provides
still water in which many species flourish.
– Bees: By pollinating plants, bees contribute to their survival. The
plants are shelter for insects, which are then eaten by other species,
like birds.
– Hummingbirds: Pollination is the reason hummingbirds are a keystone
species. In places where the numbers of hummingbirds are low, other
species of plants will take over the ecosystem.
– Sugar maple: This tree is a keystone species of the hardwood forest. It
brings water from lower levels in the ground that helps other plants.
It is also home to many insects, birds, and small animals.
How do all these organisms obtain
energy?
• Starts with the sun
– Why do we absolutely positively NEED the
sun?
• Remember the 3 different types or
organisms that indicate how they obtain
energy?
Organisms are either…
• Producers
• Consumers
• Decomposers
Producers
• Can make their own food
– photosynthesis
• Source of all the food in an ecosystem
• All organisms that cannot make their own
food ultimately depend on producers
Consumers
• An organism that feeds directly or indirectly
on producers.
– Ie; grasshoppers and rabbits are plant eaters
• Herbivores
– Shark, snake, and wolves eat other animals.
• Carnivores
– Crows, bears, and humans eat both
• omnivores
Decomposers
• After living things die, decomposers use
the dead matter as food
• Break down dead organisms into
simpler substances (kind of like our
stomachs, so that the nutrients can be
absorbed in our small intestines)
• In return, they return important
materials back to the earth (fertilizers)
• “natures recyclers”