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Modes of nutrition

Populations and Species

Autotrophs and Heterotrophs

Heterotrophic nutrition

Communities and Ecosystems

Communities

Ecosystems

Mesocosms

Chi-squared test

Energy Flow

Energy sources

Energy losses

Food chains and energy pyramids

Trophic levels and food chains

Energy pyramids

Carbon cycle

What is it?

Carbon deposition

Fossil fuels

Carbon release

Global warming and greenhouse effect

Greenhouse effect

Greenhouse gases

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Species: A group of organisms that can potentially inter-breed to produce fertile offsprings
Inter-breeding: Mating with organisms of your own species: fertile offsprings
Cross-breeding: Mating with organisms/individuals of another species: infertile offsprings
Population: A group of organisms of same species living in the same area at the same time

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Autotrophs (Most plants and algae): Make their own food  (organic molecules), contain chloroplasts: photosynthesis (CO2 + H2O + sunlight --> glucose + O2)
Heterotrophs (humans and lions): Gets the food by eating  other organisms.
Heterotrophic plants and algae
Are generally autotroph but there are some exceptions:
- Meat eating plants:
https://www.youtube.com/watch?v=wcmKT5uHgL0
- Euglena: Unicellular organism; protoctists; autotroph (contains chloroplasts - carries out photosynthesis - able to produce its own organic food) and heterotroph (feeds on dead matter and ingests it via endocytosis)
For more information see:

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Autotrophs are organisms that can produce their own food from the substances available in their surroundings using light ( photosynthesis) or chemical energy (chemosynthesis). Heterotrophs cannot synthesize their own food and rely on other organisms - both plants and animals - for nutrition. Technically, the definition is that autotrophs obtain carbon from inorganic sources like carbon dioxide (CO2) while heterotrophs get their reduced carbon from other organisms. Autotrophs are usually plants; they are also called "self feeders" or "primary producers".

Energy Production

Autotrophs produce their own energy by one of the following two methods:

Photosynthesis - Photoautotrophs use energy from sun to convert water from the soil and carbon dioxide from the air into glucose. Glucose provides energy to plants and is used to make cellulose which is used to build cell walls. E.g. Plants, algae, phytoplankton and some bacteria. Carnivorous plants like pitcher plant use photosynthesis for energy production but depend on other organisms for other nutrients like nitrogen, potassium and phosphorous. Hence, these plants are basically autotrophs.

Chemosynthesis - Chemoautotrophs use energy from chemical reactions to make food. The chemical reactions are usually between hydrogen sulfide/methane with oxygen. Carbon dioxide is the main source of carbon for Chemoautotrophs. E.g. Bacteria found inside active volcano, hydrothermal vents in sea floor, hot water springs.

Heterotrophs survive by feeding on organic matter produced by or available in other organisms. There are two types of heterotrophs:

Photoheterotroph - These heterotrophs use light for energy but cannot use carbon dioxide as their carbon source. They get their carbon from compounds such as carbohydrates, fatty acids and alcohol. E.g. purple non-sulfur bacteria, green-non sulfur bacteria and heliobacteria.

Chemoheterotroph - Heterotrophs that get their energy by oxidation of preformed organic compounds, i.e. by eating other organisms either dead or alive. E.g. animals, fungi, bacteria and almost all pathogens.

Food Chain

Autotrophs do not depend on other organism for their food. They are the primary producer and are placed first in the food chain. Heterotrophs that depend on autotrophs and other heterotrophs for their energy level are placed next on the food chain.

Herbivores that feed on autotrophs are placed in the second trophic level. Carnivores that eat meat and omnivores that eat all types of organisms are placed next in the trophic level.

References

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"Autotroph vs Heterotroph." Diffen.com. Diffen LLC, n.d. Web. 17 Apr 2018. < >

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What's the difference between Autotroph and Heterotroph? Autotrophs are organisms that can produce their own food from the substances available in their surroundings using light (photosynthesis) or chemical energy (chemosynthesis). Heterotrophs cannot synthesize their own food and rely on other organisms - both...

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Consumers: (ingest, digest, absorb organisms that are either alive or were killed recently)

1. Feed directly on autotrophs (bees, hummingbird,...), they are herbivores
2. Feed on primary consumers
3. Feed on secondary consumers

Detritivores: Feed on dead organic matter like feces, feathers, hairs, etc.  (ingest, digest internally - ex. earth worms, dung beetles and woodlice)

Saprotrophs/decomposers: Feed on dead matter (digestion is external, injestion of products, release of digestive enzymes, bacteria and fungi - ex. mucor: bread fungal species

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Different populations living together and interacting with one-another. There can be:

Positive association (presence of one promotes presence of another)

Negative association (presence of one is detrimental to presence of another)

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Communities form an ecosystem by its interactions with its abiotic environment (Soil, H2O, air,...). Ecosystems have the potential to be sustainable over a long period of time.

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Enclosed experimental area that is set up to explore ecological relationships. Because it is a contained experimental area, it can be closely controlled and variables monitored.
- Sealed glass vessels are preferable because entry and exit of matter can be prevented but light can enter and heat can leave.
- Aquatic systems are more successful than terrestrial ones.
- Mesocosms enable all variables other than independent and dependent to be kept constant
- Precise manipulation of independent variable can be made
- Accurate measurement of dependent variable

For further information and how to model a mesocosm experiment:
http://lhicks2015.weebly.com/design-process.html

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Testing for association between two species:

No association:                        - b Ho)

Yes association:                      - Positive association (H₁)    - Negative association (H₂)

Process:

1. Create coordinate plane (tape x and y axis). Then create squares (1x1 meter) and take about 100 random squares.

2. Create contingency table (enter information)

3. Calculations - see the video: https://www.youtube.com/watchtime_continue=14&v=53kYOOr5Yhk

4. Compare your calculated chi-squared number with the number of the official chi squared table (see image)                                              - If your number is greater than the one on the table, you can reject the null hypothesis.

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Sunlight:

Energy source for all life on  earth

Absorbed by producers: convert light energy to chemical energy through photosynthesis

Energy enters as sunlight and leaves a s heat (NOT CYCLED)

2nd law of Thermodynamics: Energy can not be destroyed but transferred
Food:

Consumer, detritivores and saprotrophs obatain energy from their food

There is chemical energy in carbon compounds in the food --> But light is ALWAYS the initial energy source for the whole community

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Trophic levels:
The position that any species takes in a food chain. Producer, primary consumer, secondary consumer and tertiary consumer are trophic levels.
Food chains:
Each species in a food chain feeds on the previous one, apart from the producer at the start that makes its own food by photosynthesis. Food chains commonly contain 3-5 trophic levels because only about 10% of energy and biomass is passe on from one trophic level to another. An example for a food chain:

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If only 10% of the energy and biomass is transferred - what happens to the rest 90%?

Respiration (production of energy from ATP in mitochondria), lost as heat to the environment. Living organisms can not convert heat to other forms of energy. --> for more info see video attached

Growth and metabolism

Not all parts are digested and eaten

Excretion

An organism could die before being consumed

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Energy pyramids are diagrams that show how much energy flows through each trophic level in a community. It is a representation of biomass (Total mass of group of organisms ) across trophic levels (KJ/m²yr) or (KJm⁻²yr⁻¹)

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The series of processes by which carbon compounds are interconverted in the environment.
--> Continued availability of carbon in ecosystems depends on carbon cycling.

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--> where it is stored

Carbon is present in atmosphere as CO₂ and CH₄

Carbon is present in aquatic ecosystems as dissolved carbon dioxide and hydrogen carbonate ions (when water and CO₂ combine to form carbonic acid --> dissociates to produce hydrogen carbonate ions)

Peat formation                    Brown material that consists of not-fully decomposed organic matter --> due to H₂0 being unable to drain out of soil, thus creating a waterlogged environment (rise in acidity, not suitable for decomposers and saprotrophs)

Limestone formation  Mollusks, reef-building: hard body parts --> When they die the soft parts easily decompose but the hard parts don't: formation of sedimentary rocks

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Organic matter deposited on earth as either crude oil, natural gas and coal over millenia due to high pressure and temperature

Fossil fuel reserves are finite/limited

Crude oil and natural gas: formed in porous rocks

Coal: Peat covered by other layers of sedimentation

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Respiration                              Carbon is released in the form of CO2

Methanogenisis              Production from decaying organic matter and release of methane (CH4 --> C-form) into the atmosphere by bacteria and archeans in anaerobic conditions               -  Archaens: CH₃OOH -->  CH₄ + CO2  and CH₄ + 4H₂    -->  CH₄ + 2H₂O                          -  Swamps, mud, wetlands,..

Combustion (of carbon compounds)                                    - Release of CO2 into the atmosphere - Burning of biomass and fossil fuels (since industrial revolution)

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The greenhouse effect is a natural process that warms the Earth’s surface. When the Sun’s energy reaches the Earth’s atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases.

The absorbed energy warms the atmosphere and the surface of the Earth. This process maintains the Earth’s temperature at around 33 degrees Celsius warmer than it would otherwise be, allowing life on Earth to exist.

The problem we now face is that human activities – particularly burning fossil fuels (coal, oil and natural gas), agriculture and land clearing – are increasing the concentrations of greenhouse gases. This is the enhanced greenhouse effect, which is contributing to warming of the Earth. --> Global warming

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Reside in the atmosphere

Absorb the IR radiation coming from the Earth

Re-emit part of that radiation back to the Earth

These are the 4 main greenhouse gases:
- CO 2

High concentration (ca. 400 ppm)

Lasts for a very long time       --> High effect on global warming

- H ₂ O

High concentration

Lasts for ca. 9 days                --> Not as high effect on global warming as CO₂

- CH ₄

Very small concentration

Lasts long in atmosphere for ca. 12 years                       --> Effects on global warming  all negligable

- Nitrogen oxides (NO ₂)

Very small amount and concentration --> Effects on global warming all negligable