CTY Honors Biology Unit Lesson 8.1

- Ecological Organization - Food Chains and Webs - Climates

ecology

study of organism interactions with each other and environment *living impossible without interactions

species

organisms that can breed and produce fertile offspring

population

same species in the same area

community

two or more populations in the same area

ecosystem

community + physical environment

biome

group of ecosystems with climate and organism similarities

biosphere

all life on Earth and where all life exists

environment

every factor surrounding organism

abiotic factor

non-living physical factors

biotic factors

living organisms

autotrophs

• food synthesis from inorganic compounds+usable energy sources

• consumed by others

• primary producers

• plants, some bacteria, some protists

photoautotrophs

• energy source: light (photosynthesis)

• CO2 + H2O+light energy → carbs + O2

• plants, algae, photosynthetic bacteria

chemautotrophs

• energy source: inorganic compounds (chemosynthesis [oxidation])

• CO2+H2s+O2 → carbs+sulfur compounds

• archea

hereotrophs

• dependent on others for food

• consumers

decomposers

feed on dead matter, produce detritus

• fungi+bacteria

detrivores

feed on detritus+decomposers

• earthworms, shrimp, snails

herbivores

plant-eating

• rabbits, cows

carnivores

meat-eating

• cats, dogs

scavengers

eat dead animals

• hyenas, vultures

omnivores

plants+meat-eating

• humans, bears, bigs

energy flows

• ecosystems need an energy flow

• one-way: primary producers → consumers

food chain

linear transfer of energy+matter through species

food chain components

• primary producer: grass

• primary consumer: grasshopper

• secondary consumer: beetle

• tertiary consumer: frog

• quaternary consumer: snake

food web

diagram of complex feeding relationships + intersecting food chains

*detrivores + decomposers are essential: recycle nutrients/raw materials from dead animals

food web example

• primary producers

• organisms consumed (wide variety of consumers at each level)

• decomposers/detrivores recycle energy+matter to primary producers

food web disturbances

complexity makes it difficult to predict the consequences

• human industrialization/population affect

• geological events/natural disasters affect

energy/trophic levels

only 10% of total energy is transferred in one-way direction (90% for metabolism+heat)

ecological pyramids

represent energy or matter relationships

energy pyamids

• 1st trophic level (100%)

  • primary producers

• 2nd trophic level (10%)

  • primary consumers

• 3rd trophic level (1%)

  • secondary consumers

• 4th trophic level (0.1%)

  • tertiary consumers

biomass

amount of organic matter in given level

*grams per unit of area

biomass pyramid

1*10^5 kg

1*10^7 jg

1×10^9 kg

*biomass cannot be supported as the amount of organisms consumed to support energy increases

numbers pyramid

relative number of organisms at trophic level

*can be upside down (increasing volume vs. decreasing volume) depending on how the energy needs and biomass is distributed

biogeochemical cycles

matter redistribution/recycling pathways

• abiotic+biotic factors

• biological, geological, chemical, and human activities have effects

*Law of Conservation of Mass

biological process

eating, breathing, eliminating waste

geological processes

earthquakes, volcanoes

chemical+physical processes

precipitation, lighting (weather)

human activity

agriculture, deforestation, fuel use

water cycle

*water is essential to all life: chemical reactions, universal solvent, habitat

• the transferring and recycling of water between land, organisms, atmosphere, ocean

evaporation

liquid vaporization (water from large bodies rises)

transpiration

water evaporation in planta stomata

condensation

gas to liquid change in atmosphere (clouds)

precipitation

liquid water returns to surface

runoff

water flowers across land back into bodies of water

*some absorbed by soil for plants

infiltration

water collects in underground reservoirs

carbon cycle

*extremely abundant element: proitens, carbs, nucleic acids, fat

• entering and exiting of CO2 with atmosphere

respiration

CO2 released/eliminated when )2 and glucose combine

photosynthesis

CO2 taken in with water+energy to make glucose

fossil fuels

CO2 storage when organic matter decomposes and fossilizes (CO2 released when burnt)

CO2’s effect on global warming

• the volume of CO2 being released from burning fossil fuels is too much for plants, especially with deforestation

• lets in light, traps heat (greenhouse gas) which warms the earth (global warming)

nitrogen cycle

*extremely abundant in living organisms: nucleic acid, protein (78% os air is N2/nitrogen gas)

• conversion of N2 into usable compounds and vice versa

nitrogen fixation

bacteria convert N2 → ammonia NH3

nitrification

bacteria convert ammonia/ammonium → nitrites NO2- and nitrates NO3-

• primary producers use as nitrogen source

• consumers get nitrogen from primary producers

denitrification

bacteria convert nitrates NH3 → N2

atmospheric nitrogen fixation

lighting

nitrogen cycle steps

1. nitrogen-fixing bacteria turn N2 into usable compounds (ammonia/ammonium)

2. nitrifying bacteria convert ammonium first into nitrates+nitrites

3. plants assimilate the nitrates

4. animals consume plants

5. animals/plants die, decomposers turn organic nitrogen into ammonium

6. denitrifying bacteria turn nitrates to N2 to atmosphere

phosphorus cycle

*in nucleic acids

• not in atmosphere: land (rocks+soil) and ocean (marine sediments)

• erosion+weathering dissolve phosphorus from rocks/soil

• plants absorb phosphorus into organic compounds

• consumers receive organic phosphorus, rest dissolves into water, then oceans

• after death phosphorus is recycled back into environment