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Flow of matter and energy in the ecosystem

Introduction:

 In addition to the climatic and edaphic factors that influence the distribution of living beings, other factors govern the balance naturally in ecosystems, these are the trophic, intra-specific, and interspecific. Therefore, the ecosystem is an extremely complex structure within which links are established between living beings; through these links, we witness a transfer of matter and energy.

Existing trophic relationships between living beings:

Within ecosystems, living beings ensure their survival by establishing diverse and complex trophic relationships. 
observed trophic relationships: 
- Parasitism: It is an obligatory or temporary trophic relationship between two species of which one is the beneficiary called the parasite, and the other loser, called a host.

- Predation: Relationship that binds two or more animal species living in the same ecosystem (Interspecific), where the weak are eliminated (The law of stronger).

- Commensalism: Direct or indirect interaction between two species whose only one benefits with or without harm to the other.

  - Cooperation or mutualism: Non-compulsory mutualistic relationship between two cash, where both are beneficiaries. - Symbiosis: A permanent relationship between two different species, which translates into beneficial effects for both.

- Competition: It is when at least two species colonize the same place and exploit the same source (Food, habitat, light...), each one uses its own means to be profitable.

- Saprophytism: An organism is saprophytic when it is able tocan feed non-living organic matter, breaking it down.

Food webs:

An animal's diet is all the food it takes from its environment.

a- Methods used to know the diet of an animal:

 Direct observation of animals.
 Observing the traces of a meal.
 Examination of the contents of the digestive tract.
 Excreta analysis.
 The analysis of a ball of raptor regurgitation.

b- The different types of diets:

 The vegetarian diet (phytophagous): feed mainly on plants.
         Herbivores only eat grass (the cow);
        Granivores only eat seeds (cross beak);
        Frugivores only eat fruits (monkeys);
        The nectarines feed only on nectar (the hummingbird).
The carnivorous diet (Zoophage): They feed mainly on the food of animal origin.
        Insectivores, only eat insects (Swallow);
        Piscivores only eat fish (the osprey);
        Scavengers eating abandoned corpses (The vulture).
 The omnivorous diet: They feed on both foods of animal origin and foods of plant origin. (The planctophage: whale).

Food chains:

A food chain is the succession of living beings that are linked together through a food relationship.
In a food chain, the relationships are represented by arrows which
reflect the transfer of matter and energy.

balance sheet

In an ecosystem, there are three categories of organisms:
Producers (P): these are chlorophyllous plants. They occupy
always the first link in a food chain. They are autotrophs (They make their own organic matter through the phenomenon of photosynthesis).
Consumers (C): these are heterotrophic animals that
feed on the existing organic matter in living beings, and according to
what they ingest we distinguish:
Primary consumer or first-order consumer (CI): These are the herbivores that feed directly at the expense of the producer.
Secondary or second-order consumer (CII): These are carnivores that feed on herbivores.
Tertiary or third-order consumers (CIII): These are consumers
carnivores that feed on carnivores (CII).
The decomposers (D): occupy the last link in the chain of eating. They degrade organic matter from all previous categories.

The quantitative study of food relations:

 Primary productivity and secondary productivity:

In an ecosystem, autotrophic living beings (chlorophyllous plants) convert light energy into chemical energy contained in matter organically produced: this is the primary productivity. Some of this material organic is consumed by heterotrophic living beings (Consumers and decomposers), to produce their own organic matter: this is the productivity secondary.

 The flow of matter and energy:

Chlorophyllous plants produce their organic matter using salts minerals, CO2, and solar energy. Herbivores build their organic matter from the plants they consume, and carnivores develop their matter
organic from other animals eat. We, therefore, observe a transfer of matter and energy from one trophic level to another in ecosystems. This is
the flow of matter and energy which is expressed by the following formula:
A = PN + R (A = energy flow, PN = net production, R = energy loss)

balance sheet

The flow of matter and energy in ecosystems begins at the level of chlorophyllous plants (primary production). This flow crosses the different levels trophic, while constantly decreasing. And this is because of the unused parts; Nope assimilated, and portions consumed as part of cellular respiration to produce energy essential for all biological activities

Pyramids of biomass and pyramids of energy:

Pyramids are graphical representations in the form of rectangles superimposed and centered, whose length is proportional to the parameters studied while the width is constant.
    We distinguish :
Pyramid of numbers: representation of the number of individuals.
Biomass pyramid: representation of the variation in biomass.
Energy pyramid: representation of the variation in the amount of energy.

The ecosystem and its dynamic aspects:

Birth and evolution of an ecosystem:

The main steps in creating an ecosystem are:
 The rocks in the middle are altered by weathering and chemical action in rainwater.
 The soil thus formed, purely mineral is enriched by droppings (excrement) birds, and other mammals. (Contribution of pollen grains by the wind and by migrating birds).
 Installation of pioneer species such as lichens, mosses,
bacteria, and fungi, improves the primitive soil.
 Insects and worms occupy the improved soil, on which appear the
early ferns and flowering plants.
 The gradual population of the environment by plants and animals.
 The establishment of a natural balance between living beings, soil, and climate, promotes an increase in the number of species and individuals in the ecosystem.
 Achieving the climax.

Definition of climax:

The climax is the final stage in the evolution of an ecosystem. It represents the state balance between the different animal and plant species that live in the same biotope and in climatic and edaphic conditions well determined.

The dynamism of the ecosystem:

The ecosystem is characterized by its dynamism (evolves from one state to another state), as a result of the variations that affect the links and relationships that exist between the various components of this ecosystem.

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