IB DP Biology HL C4.2 Transfers of energy and matter Flashcards

[q] C4.2.1—What are open systems?

What are closed systems?

Which applies to ecoystems?

[a] Ecosystems function as open systems, where both energy and matter can freely enter and exit.

Closed systems only permit the transfer of energy into and out of them

Open systems like ecosystems exchange matter through processes like nutrient cycling;

and energy through photosynthesis and respiration.

[q] C4.2.2—What is the principal source of energy that sustains most ecosystems

[a] Sunlight is the primary source of energy for most ecosystems; 

driving photosynthesis in plants, algae, and certain bacteria;

Exceptions include ecosystems in caves or deep ocean hydrothermal vents, 

where organisms rely on chemosynthesis or detritus from other sources.

[q] C4.2.3—How does chemical energy flow through food chains?

[a] Chemical energy is transferred from one trophic level to another; 

in food chains; starting with autotrophs and moving up to various levels of consumers;

This transfer occurs through feeding;

on the previous trophic level, absorbing and utilizing their stored chemical energy;

[q] C4.2.4—How do you construct a food chain?

[a] Food chains represent the linear flow of energy and nutrients from producers to consumers.

[q] C4.2.4—How do you construct a food web?

[a] Food webs represent the flow of energy through a network of organisms

[q] C4.2.5—How is energy supplied to decomposers?

[a] Decomposers, like fungi and bacteria, receive energy from carbon compounds;

in organic matter from dead organisms, faeces, and decaying plant and animal parts;

They play a crucial role in breaking down organic matter, recycling nutrients to the soil;

[q] C4.2.6—How do autotrophs provide their own energy?

[a] Autotrophs are organisms that synthesize organic compounds; 

from simple inorganic substances, using external energy sources;

[q] C4.2.7—What are photoautotrophs? How do they compare to chemoautotrophs?

[a] Photoautotrophs, like plants and algae, use sunlight energy;

for photosynthesis; converting light energy into chemical energy;

Chemoautotrophs, such as certain bacteria;

obtain energy from oxidation reactions;

e.g. iron-oxidizing bacteria use the energy from oxidizing iron compounds;

[q] C4.2.8—What are heterotrophs and how do they obtain carbon to synthesis carbon compounds?

[a] Heterotrophs are organisms that cannot synthesize their own food;

They rely on consuming other organisms or organic compounds for energy and nutrients;

this includes herbivores, carnivores to omnivores;

each digesting and assimilating complex carbon compounds like proteins and nucleic acids;

[q] C4.2.9—How is energy released in both autotrophs and heterotrophs?

[a] Both autotrophs and heterotrophs release energy through the oxidation of carbon compounds;

during cellular respiration;

This process converts organic molecules into ATP;

providing energy for cellular functions;

[q] C4.2.10—What are trophic levels?

How are organisms classified into trophic levels?

[a] Trophic levels are the positions of organisms in a food chain or web;

Autotrophs are at trophic level 1;

primary consumers (herbivores) are at trophic level 2;

secondary consumers (carnivores or omnivores) are at trophic level 3;

and tertiary consumers (top predators) are at trophic level 4;

organisms can occupy more than one trophic level;

[q] C4.2.11—How do you construction energy pyramids?

What do they show?

[a] They show the energy at every level of a food chain;

this is measured in kJ m-2 yr-1

[q] C4.2.12—Why does energy availability decrease at each stage in food chains?

[a] In food chains, there is a significant loss of energy at each trophic level;

approximately 90% of energy is lost; only 10% is passed on;

primarily due to metabolic processes and inefficiencies in energy transfer;

heat is lost as a result of cellular respiration;

indigestible parts of organisms do not release their energy;

and energy is used in homeostasis in organisms, maintaining themselves through life processes;

e.g. excretion;

[q] C4.2.13—How is energy lost in both autotrophs and heterotrophs primarily?

[a] Both autotrophs and heterotrophs lose energy as heat due to the conversion of chemical energy in cell respiration;

Energy transfers are not 100% efficient, so heat is produced both when ATP is generated and used in cells;

[q] C4.2.14—What restricts the length of food chains and food webs?

[a] Due to energy losses at each trophic level;

there are fewer organisms or smaller organisms at higher levels;

This limits the number of trophic levels;

as the available energy diminishes, reducing the total biomass at each successive level;

The energy content per unit mass however, does not necessarily decrease with higher trophic levels.

[q] C4.2.15—What is primary production in autotrophs?

[a] Primary Production refers to the accumulation of carbon compounds in biomass;

by autotrophs such as plants, algae, and certain bacteria;

It is usually measured in mass of carbon per unit area per unit time ;

(e.g., grams per square meter per year, g m^-2 yr^-1);

Different biomes have varying capacities to accumulate biomass;

For instance, tropical rainforests exhibit high primary production due to abundant sunlight and moisture, whereas deserts have much lower rates;

[q] C4.2.15—What is secondary production in heterotrophs?

[a] Secondary Production is the accumulation of carbon compounds;

in biomass by heterotrophs (organisms that consume other organisms for energy);

econdary production is typically lower than primary production;

This is due to the energy loss during cellular respiration in heterotrophs; 

so biomass decreases when carbon compounds are converted to carbon dioxide and water in cell respiration;

[q] C4.2.17—How do you construct carbon cycle diagrams?

[a]

[q] C4.2.18—What are carbon sinks and carbon sources? How are ecosystems carbon sinks and sources?

[a] Ecosystems act as carbon sinks when the rate of photosynthesis (carbon uptake) is greater than respiration; (carbon release);

leading to a net uptake of carbon dioxide from the atmosphere;

Conversely, when respiration rates exceed photosynthesis, ecosystems become carbon sources;

releasing more carbon dioxide into the atmosphere than they absorb.

[q] C4.2.19—How is carbon dioxide released from organic sources?

Which ones are significant?

[a] Combustion of biomass;

peat;

coal;

oil;

and natural gas releases significant amounts of carbon dioxide into the atmosphere;

These materials, considered carbon sinks, vary in their formation dates, from recent biomass to ancient fossil fuels;

[q] C4.2.20—What is the Keeling Curve?

What explains its shape?

[a] The Keeling Curve illustrates the concentration of atmospheric carbon dioxide and shows both annual fluctuations;

and a long-term upward trend;

Annual fluctuations are attributed to seasonal variations in photosynthesis and respiration;

where in northern hemisphere summer there is net intake of carbon dioxide and in winter, a net output;

while the long-term trend reflects increased carbon dioxide levels due to human activities, primarily fossil fuel combustion;

but also deforestation;

[q] C4.2.21—How do photosynthesis and respiration depend on each other?

[a] Aerobic respiration and photosynthesis are interdependent processes;

Respiration in heterotrophs and some autotrophs produces carbon dioxide;

which is used in photosynthesis by autotrophs;

Conversely, photosynthesis produces oxygen, which is essential for aerobic respiration;

This cycle represents a significant interaction between autotrophs and heterotrophs;

with vast annual fluxes of these gases;

[q] C4.2.22—How does recycling of all chemical elements required by living organisms in ecosystems occur?

[a] In ecosystems, all chemical elements required by living organisms, not just carbon, are continuously recycled;

Decomposers play a pivotal role in this recycling process; 

breaking down organic matter and returning essential elements like carbon, nitrogen, phosphorus, and sulfur to the environment, making them available for reuse by other organisms;

[q] What is a ecosystem?

[a] A unit that contains all living things the interact with their surroundings

[q] What is open ecosystem?

[a] A ecosystem where energy and matter can move in and out

[q] What is a closed ecosystem?

[a] A ecosystem where energy cannot move in and out

[q] What are the 3 types of organisms?

[a] Autotrophs/producers, Heterotrophs/consumers, Saprotrophs/decomposers

[q] What are the 2 types of autotrophs/producers?

[a] Photo autotrophs and Chemo autotrophs

[q] What are autotrophs?

[a] They synthesise their own carbon compounds by utilising one form of energy + inorganic compounds Carbon compounds being, glucose, amino acids, fatty acids, nucleotides into starch, triglycerides, proteins, DNA rRNA (Nucleic Acids)

[q] What are photoautotr

[a] Organisms that use photosynthesis for nutrition Absorb light energy and CO2 (inorganic compounds) through the chlorophyll pigment To synthesise carbon compounds

[q] How does photosynthesis work in aquatic plants?

[a] CO2 that is polar dissolves into water to create H2CO3 carbonic acid splits into HCO3 and H+, HCO3 is the dissolvable form of CO2 and is taken into the plant

[q] What are chemoautotrophs?

[a] Chemical – energy source Done by prokaryotes – Bacteria, Archaens Preform chemosynthesis

[q] What is chemosynthesis?

[a] The inorganic compound is the substrate that gets oxidised to yield ATP

[q] What is reduction and oxidation reactions

[a] Reduction is the gaining of electrons and lose of O2 Oxidation is the loss of electrons and gain of O2

[q] What are Heterotrophs/Consumers?

[a] Consumers feed on consumers

They undergo internal digestion

1. Ingestion

2. Digestion

3. Absorption

4. Assimilation digested food molecules become part of the body

5. Egestion

[q] What are Detritivores?

[a] Organisms feeds on dead and decaying parts of organism

e.g vultures, earthworm same internal digestion

[q] What are Saprotrophs/Decomposers?

[a] Bacteria or Fungi, decomposing the dead and decaying organic matter, can feed on all the trophic levels

[q] What is saprophytic nutrition?

[a] External digestion

Secretes digestive enzymes

E.g. Mycelium

Secreting the digestive enzyme makes bread glucose soluble

Does facilitated diffusion and active transport, to collect nutrients in the fungi cell

[q] What is a food chain?

[a] A flow chart the represents the flow of energy from one trophic level to the next, and always has a producer as their beginning

[q] What is a food web?

[a] Interconnecting food chains that show interspecific relationship among the different species

[q] What is the principle source of energy in a ecosystem?

[a] Sun – light energy goes to producers/Autotrophs

[q] How is energy produced in autotrophs and heterotrophs?

[a] Carbon compounds into mitochondria produces ATP

[q] What are the uses of ATP in cells?

[a] 1. Synthesise macromolecules (polymers)

2. Movement

3. Active Transport

[q] How much energy is lost through each trophic level?

[a] 90%

[q] What are the reasons for energy loss in trophic levels?

[a] 1. Respiration/Movement

2. Egestion / Removal of undigested food material

3. Insufficient consumption of the body parts

[q] What is primary production in autotrophs?

[a] Gross primary production all the energy source is utilised to synthesise carbon compounds

Net primary production actual availability of carbon compounds

[q] What is production on autotrophs?

[a] GPP what all being consumed from another organism and NPP actual production

NPP = GPP – Cell respiration

GPP > NPP

[q] Carbon Cycle

[a] Know how to draw it

CO2 is 0.04% of our atmosphere

Pool : where carbon is stored e.g fossil fuels

Flux: Carbon gas transferred between organisms (processes)

[q] What is carbon sequestration?

[a] Removal of carbon from the carbon cycle

[q] What are some carbon sinks?

[a] 1. Woods – Biomass – dry mass without water stored in trees

2. Peat – 10000 years dead and decaying parts of plants buried under soil – anaerobic condition bacteria stops decomposing

3. Coal (250-350 mya) dead and decaying plant parts – anaerobic acidic and high pressure

4. Natural gas and oil (550 mys) Found under the ocean, dead and decaying plants and animal parts anaerobic acidic and high pressure

[q] Keeling Curve

[a] A graph that plots the ongoing change in concentration of carbon dioxide in Earth’s atmosphere since the 1950s
Annual

Oct – may high conc co2 high respiration

May – oct low conc co2 low respiration

shows interdependence of respiration and photosynthesis

Long term trend:

1959 – until, increased CO2 conc due to deforestation and combustion

[q] Where are the chemical elements recycled?

[a] C – Air

H – Soil

O – Soil

N- Soil

P – Soil

[q] What is the relationship between abiotic and biotic recycling?

[a] Elements are replaced to abiotic environment by respiration and decomposition into abiotic factors then through photosynthesis it turns int abiotic factors.

[q] Explain the process by which energy enters and flows through ecosystems

[a] 1. Sunlight is the initial energy source for the ecosystem

2. This sunlight is converted into chemical energy by plants through photosynthesis.

3. This turns inorganic compounds into organic compounds in this case glucose C6H12O6

4. These organic compounds are used as energy, growth etc.

5. These compounds get passed along the food chain

6. Cellular respiration occurs releasing a lot of energy/ATP

7. Heat is lost as a result of respiration

8. Only 10% of energy is passed through each trophic level

9. Energy is also lost through bone and hair in which are not eaten

10. Energy also lost in the urine and faeces

11. Eventually decomposers remove energy from dead bodies

12. Energy is not recycled

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