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Unit 2 Review
Topics
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Ecosystems- energy, food chains, webs
Biomes (general, not specific)
Nutrient cycles
Succession and Eutrophication
Biodiversity
– Importance of
– Threats to
– How to protect
Ecosystems
• Producers, consumers
• Who eats what? Herbivores, Omnivores
and Carnivores
• Trophic levels and energy- more energy at
the bottom (plants) than top (predators)
• Role of decomposers
• Be able to read a food web/chain and
identify trophic levels
Biomes
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Difference between weather and climate
Climate, altitude, latitude determine flora
Plant life determines animal life
Know the biome YOU live in
Nutrient Cycles
• Carbon, Nitrogen, Phosphorus- never run out,
just continually cycle through earth systems
• C-cycle:
– Photosynthesis/Respiration: trades carbon between
life and atmosphere
– CO2 can be dissolved in surface waters and used by
marine life
– C can be stored in sediments to become future
limestone or fossil fuels
– Humans burning fossil fuels release more CO2 into
atmosphere
Nutrient Cycles
• N-cycle
– We cannot use atmospheric Nitrogen (N2 with
a triple bond)
– Nitrogen fixation converts N2  nitrates,
ammonia which plants can use
– N fixing bacteria do this in soils and roots of
legumes
– Denitrification: bacteria convert usable
nitrogen back to N3
– Humans: fix nitrogen to make fertilizers
Nutrient Cycles
• P-cycle
– Phosphates found in rocks
– Weather and water dissolve phosphates in
water for plants to uptake
– Humans get P from plants and animals
– Humans mine phosphates and use them as
fertilizers
Eutrophication
• Succession happening too quickly in an
aquatic ecosystem
• Excessive N and P enter ecosystem,
algae blooms
• Decomposers eating dead algae use up all
available oxygen
• Lake/pond slowly suffocates life inside
• Human influence: fertilizer runoff, animal
waste, detergents
Succession
• The evolution of an ecosystem
• Primary- no soil there before (bare rock)
• Secondary- soil present, ecosystem
disturbed
• Pioneer species- first to colonize area
• Climax community- end result, mature
ecosystem
• Takes a long time- 100-2000 years
Biodiversity- Importance
• Agriculture- need different crops in case one
fails
• Medical- untapped medicines in organisms yet
to be researched/discovered
• Ethical- all organisms deserve right to life
• Aesthetic- variety is pleasing, beautiful,
ecotourism
• Ecosystem stability- remove one species, the
whole system could collapse; everything’s
important
Biodiversity- Threats
• Mass extinctions have happened naturally
but humans are creating their own by
– Habitat destruction and fragmentation
– Introducing invasive species
– Pollution
– Over-hunting/harvesting
– poaching
Biodiversity- Protection
• Saving a species: captive breeding, preserving
genetic specimens, zoos
• Ecosystem approach
– Setting aside wilderness areas, nature preserves,
national parks
– Federal Laws: Wilderness Act, ESA
– International treaties: CITES to help poaching and
animal trade
• Why don’t people care? –not a priority, unaware
Species?
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Endemic- native; only found there
Keystone- crucial to function of ecosystem
Pioneer- colonizes landscape first
Invasive- non-native, destructive
Threatened- about to be endangered
Endangered- about to be extinct
Don’t forget...
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Biodiversity Hotspot Socratic/Articles
Case Study
Parking Lot lab
Biome project
HW packet
Trash Ball Review Game
• 2 teams
• Everyone has number on each team: 1A,
1B, 2A, 2B
• Each person is asked a question
individually
• If correct, +1 point AND they can shoot
trash ball into basket for extra points
– Across room +3
– 6 feet away +1