1. Ecosystems

2. Important Terms
Ecosystem = a group of organisms and how they interact with their living and nonliving environment
Niche = an organisms role
Biotic = living or having lived recently
Abiotic = nonliving, long dead
Producer = converts energy from the sun, also called an AUTOTROPH

3. Consumer = eats other living things, also known as a HETEROTROPH
Primary, Secondary, Tertiary, Quaternary
Body of water = lake, river, pond, etc
Food chain = each organism feeds on the one below it
Food web = overlapping food chains in a community

4. Types of heterotrophs Herbivores = eat plants Carnivores = eat animals
Omnivores = eat both plants and animals (omni = all)
Detritivores = eat dead matter (called “detritus”)
Decomposers = break down organic matter

5. Biodiversity = diversity of life
Decomposer
Organic matter = was or is living, made mainly out of carbon
Inorganic matter = non living, not made out of carbon
Biodiversity = diversity of life

6. Biosphere = the part of the earth where life exists
Environment = all the external factors influencing the life of organisms, such as light or food supply
Photosynthesis = to convert energy from the sun (more details to come later)
Population = the number of individuals in a species in one ecosystem

7. For the following slides, write in your notes whether the picture is a food web or food chain
List the producers and consumers in the pictures and what they eat.

13. Biogeochemical Cycles
What is a Biogeochemical Cycle?
Only so much matter on earth because it is acts as a closed system.
Energy enters as sunlight, but no matter usually exits or enters.
Open system: Energy AND matter are exchanged.
These cycles act as a way to recycle matter within the biosphere from one form to another.

14. Energy Vs. Matter Energy is TRANSFERRED Matter is TRANSFORMED
One-way flow of energy through food-chains and food webs.
Energy from sun goes to plants, which then goes to consumers.
Each trophic level loses ~90% of energy as heat.
Only 10% of energy is used for life processes.
Matter is TRANSFORMED
This is why we have biogeochemical cycles.
Only have a given amount of matter because Earth is a closed ecosystem.

15. Nutrient Cycles Carbon - key ingredient in living tissue
“Carbon-based” life forms
Nitrogen - required for amino acids used in protein synthesis
What are our sources of protein?
What do we use proteins for?
Phosphorus - required for DNA and RNA
Why is this important?

16. Water Cycle
Water is required by all living things on Earth, including us.
Cycles through atmosphere, ocean, and land

18. Water Cycle Major processes that bring water into the atmosphere
Evapotranspiration
Evaporation - water heats up, forming water vapor, which then moves into atmosphere.
Transpiration - water from plant leaves evaporates.
Condensation
Cloud formation as water vapor in atmosphere cools, condensing into the small droplets that form clouds.

19. Water Cycle Major process that brings water out of the atmosphere:
Precipitation
Droplets that formed clouds become to large and are released as snow, sleet, hail, or rain.

20. Water Cycle Processes on land: Runoff Seepage (aka infiltration)
Precipitation “runs” along land until it reaches a body of water, such as a lake, river, or ocean.
Seepage (aka infiltration)
Precipitation “seeps” (moves into) soil to form ground water below the soil’s surface.
Root uptake
Plants absorb ground water from soil via their roots.

23. Carbon Cycle How is carbon taken up and released?
Photosynthesis, respiration, decomposition
Erosion, volcanic activity, and other geological activity
Fossil fuel formation (deposition)
Human activity
All these activities transfer carbon dioxide.

24. Carbon Facts 71% of world’s carbon is in the oceans.
Mostly as carbonate and bicarbonate (dissolved ionic forms of carbon dioxide).
22% exists as fossils.
3% contained in dead organic matter and phytoplankton.
3% held in terrestrial ecosystems.
Only 1% within the atmosphere as carbon dioxide.

25. Carbon Cycle How can carbon get into the ocean?
Respiration by ocean animals
Precipitation that contains dissolved carbon dioxide
Erosion of carbonate rocks formed from animal skeletons and shells

30. Phosphorus Cycle Where is a majority of phosphorus located?
On land in rock and soil minerals.
In the ocean as sediment.
Small amount in living organisms, bound within organic molecules such as DNA and RNA as well as in skeletons of animals.
Ca5(PO4)3OH (80% skeletons)
Unlike other nutrients, it DOES NOT enter the atmosphere.

31. Phosphorus Cycle What is the major form that phosphorus is found in?
Phosphate compounds (PO43-)

34. Nitrogen Cycle What form does most nitrogen exist in?
Nitrogen gas in the atmosphere (N2)
Why is this a bad thing?
This form is not readily usable by most organisms and is often considered inert.
“Inert” because of a triple covalent bond, which is a very strong chemical bond.

35. Nitrogen Cycle How do we get to a usable form?
Bacterial nitrogen fixation
Atmospheric nitrogen fixation
Decomposition and excretion
Haber-Bosch process = synthetic fertilizer
What are these usable forms?
Ammonia (NH3), Nitrate (NO3-) and nitrite (NO2-).

36. Nitrogen Cycle What can “fix” nitrogen to a usable form? Bacteria
On root nodules of legumes such as beans; convert nitrogen gas to ammonia.
In soils, convert ammonia to nitrates and nitrites
Enzyme necessary for this requires that no oxygen be present.

37. Nitrogen Cycle What process removes usable nitrogen? Denitrification
Bacteria convert nitrates back into nitrogen gas