Ecology Flashcards
What are species?
Group of organisms
- capable of reproducing
- create fertile offsprings
What is a population?
- the same species
- living in the same area
- the same time
What is a community?
- all populations in given ecosystem
- interaction
What is an ecosystem?
- community
- habitat
- biotic and abiotic things
What are autotrophs?
- organisms that produce their own energy from sun
- inorganic → organic
What are heterotrophs?
- organisms that obtain carbon compounds through process of feeding
- consumers (living things)
- detritivores (digest inside)
- saprotrophs (digest externally)
Exceptions to definition of species
- bacteria reproduce asexually
- hybrid fertility
Exceptions to autotrophs
- mixotrophs
- Euglena gracilis (autotrophic and detritivore)
- plants and algae that are parasitic (take from others)
- no chloroplasts
How is a relationship in an ecosystem depicted?
- food chains
- producers → primary consumers → secondary producers → …
- 5 levels
- food chains intersect = food web
Nutrient cycles
- Autotrophs produce energy from abiotic environment
- Consumers obtain nutrients
- Saprotrophs and detritivores return nutrients to abiotic environment
What is self-sustainability?
- ecosystem sustainable over long time
- no additional nutrients needed (recycling)
- energy available (constant supply needed – sun)
- detoxification of waste products (by bacteria)
Mesocosms
- part of ecosystem
- for experiment
- all things necessary: light, temp, autotrophs, heterotrophs
- if saprotrophs don’t consume = excess waste
Why is biodiversity important?
- if one element of food chain dies → rest breaks
- food webs avoid this
How is energy converted?
- light energy → chemical energy
- photosynthesis by autotrophs (plants, eukaryotic algae, cyanobacteria)
- chemical energy used by autotrophs and heterotrophs
What are non-plant photosynthetic organisms?
- cyanobacteria
- other bacteria
- purple
- protists
- phytoplankton
- multicellular algae
- lichens (porosty)
Why are there only 5 levels of food chains?
After 5 there is little energy = no benefit of eating
How is light absorbed?
100% sunlight → 47% non-bioavailable to plants → 53% left → 30% of photons are lost → 37% absorbed photo energy → 24% lost due to wavelength mismatch
How is energy used?
ATP → metabolism → heat / chemical waste (CO2 and water)
How is energy lost during cell respiration and in the food chain?
- energy released during respiration
- heat is not converted
- lost energy
- during cell respiration
- not only ATP but also heat
In the food chain
- only parts of the organisms are consumed
- ex. parts of plant or bones
- indigestible parts
- excreted in feces
What is carbon pool?
- other name: reservoir
- system which can accumulate or release carbon
What is a flux?
- process of exchange of carbon between two pools
- the quickest → photosynthesis
How does CO2 move in water and in land?
Water
- dissolved gas or H2CO3
- H2CO3 → H+ + HCO3-
- pH of water drops
- autotrophs use this to make carbohydrates
- entire surface of leaves
Land
- plants absorb CO2
- through stomata
- plants use it for photosynthesis
- gradient between cells and air/water
How is CO2 produced?
- cell respiration
- non-photosynthetic cells
- roots in plants
- animal cells
- saprotrophs
- fungi digest dead organic matter
What is compensation point?
intake of CO2 = output of CO2
How is CO2 used in aquatic ecosystems?
- CO2 + H2O → H2CO3 → H+ + HCO3-
- dissolved or in form of hydrogen carbonate
- used by autotrophs in water for photosynthesis
- whole surface area of leaf absorbs
- excreted by non-photosynthetic cells during respiration
How is methane produced?
- bacteria from organic matter to organic acids, hydrogen, alcohol, CO2
- bacteria from organic acids and alcohol to acetate, CO2, hydrogen
- archaeans produce methane from CO2, H2, acetate
- CO2 + 4H2 → CH4 + 2H2O
- CH3COOH → CH4 + CO2
What are methanogenic archaeans?
- methane from CO2, H, acetate
- anaerobic respiration in wetland, marine sediments, digestive tract of ruminant animals (cows, sheep, goats)
What happens to the methane later?
- stays in ground
- diffuses to atmosphere
How does a cow digest cellulose?
- methanogenic archaeans digest anaerobically
- energy used as fuel
What are consequences of methane oxidation?
- CH4 + O2 → CO2 + 2H2O
- contribution to greenhouse effect
- not too much methane in atmosphere
How is peat formed?
- saprotrophs need oxygen from air spaces in soil
- water can’t drain out = waterlogged and anaerobic soil
- saprotrophs can’t survive there → matter is not fully decomposed = acidification (later develops and inhibits saprotrophs)
- compression
How are fossil fuels formed?
- partially decomposed organic matter
- coal: peat compressed + heat
- oil and natural gases: mud at the bottom of sea
How does combustion occur?
- producing CO2
- fires (natural or not)
- combustion of organisms
- burning fossil fuels
What is composed from CaCO3?
- molluscs shells
- hard corals produce exoskeletons
- when they die CaCO3 is broken down in acid but stable in rest
- precipitate
- limestone
What is climate?
- long-term weather patterns.
- weather — momentary state
- climate is based on temperatures and precipitation (how weather varies, seasons, etc.)
How is climate described?
By changes in temperature, wind, pressure, precipitations, sunlight, etc.
What are contributors of climate change?
- climate change is a natural process
- depends on variations in each orbit, changes in solar activity, volcanic activity, latitude, ocean currents, winds, distance from the ocean
- influenced by greenhouse gases
What are components of atmosphere?
nitrogen, oxygen, carbon dioxide, water vapour
Why are greenhouse gases contributing to global warming?
- infrared radiation absorbed
- 1% of Earth’s atmosphere
What are the most significant greenhouse gases?
CO2 and water vapour
What is greenhouse effect?
- thermal radiation (IR) from planet is absorbed
- re-radiated in all directions
On what does greenhouse impact of gases depend?
- ability to absorb long-wave radiation
- concentration in the atmosphere
Why doesn’t water vapour control global warming?
- water vapour accelerates global warming
- reabsorption of heat → more vapour
- cycle starts when CO2 triggers global warming
Which gases absorb what?
- 30% of UV radiation by ozone
- 70% of radiation absorbed at Earth’s surface and converted to heat
- 80% of IR radiation by greenhouse gases and reemitted
How does greenhouse effect work?
- short waves from sun absorbed by Earth
- reemission with long waves
- greenhouse gases do that
- heat in the atmosphere
How are levels of CO2 and temperature known?
CO2
- ice builds up
- air bubbles are caught
- this way CO2 concentration is analysed
Temp
- ratio of hydrogen isotopes in water
What is climate sensitivity?
- measure of how much Earth’s surface will warm up after doubling CO2 in atmosphere from pre-industrial levels
- between 2.6℃ - 3.9℃ (66% confidence)
What are the consequences of increased CO2?
- climate change → global warming / storm severity / sea level rise
- ocean acidification
What happens when an ocean acidifies?
- pH = 8.2 → 7.8
CO2 + H2O → H2CO3 → HCO3-
CO32- + Ca2+ → CaCO3 - ocean acidifies = more H+
CO32- + H+ → HCO3- - shells are thinner, coral dies
How is it known that human actions increase CO2 levels?
- counted
- post-industrial era
- C-13 to C-12 ratio
