Mouloud Mammeri University Communication and expression techniques II

Biological and Agronomic Sciences Faculty L2 Biological Sciences L. SADI

Biology conservation

Part one: Ecological interactions

Ecosystem is defined as a system where biotic and abiotic components interact to function
as a single unit. Since, in order to survive, grow and reproduce, every individual on earth
requires some sets of environmental conditions. These sets of favourable conditions are
essential to maximize the role of species in its habitat. Since resources are not uniformly
distributed across the landscapes, species cannot utilize the entire available resources. They
occupy a part of it which is often competitively dominant region of entire niche.

I/-Ecological interaction:

The term Symbiosis is used in everyday life; in ecology symbiosis is a close ecological
association occurring between the individuals of two or more different species for the long
period of time.

This term can be used to describe all types of biotic interactions. It is also recognized as one
of the essential forces behind evolution. We can define ecological interactions as a direct or
indirect association between organisms in an ecosystem. These interactions can be between
Plant-Plant; Plant-Animals or Animals-Animals.

These interactions influence the populations of interacting species. Prepending upon the
nature of effects on the interacting organisms, these interactions can be classified into three
broad categories: positive, negative and neutral interactions.

1/- Positive interactions:

When two organisms living in a defined geographic area, they interact with each other; during
the interaction, neither individuals of one species benefits the individuals of the interacting
species or both species benefit in the partnership. There are two kinds of such interaction exist
in ecosystem: mutualism and commensalism.

1-1/- Mutualism:

We can define mutualism as a symbiotic relationship occurring between the individuals of

two different species, in which both the individuals of association benefit.
Mouloud Mammeri University Communication and expression techniques II
Biological and Agronomic Sciences Faculty L2 Biological Sciences L. SADI

Individuals of each interacting species grow, survive and reproduce more effectively in the
presence of the other interacting species. Since, both interacting species benefit from the
interaction, it’s a win-win condition, neither of species is harmed by the other.

Benefits may include essential resources such as food, space, defense against predators,
pollination, and dispersal and so on.

1-2/- Commensalism:

It was coined by Pierre-Joseph Van Benden in 1876, which means “sharing a table”. It can be
defined as an ecological interaction between two or more species in which one of the species
benefits while the other remains unaffected-i.e. neither suffers nor benefits.

It often exists between a larger host (an organism that provides the benefit but is unaffected)
and a smaller commensal (an organism which is benefited from the interaction).such
interactions may exist between the individuals of the same species aor different species.

2/- Negative interactions:

They are ones that have a direct or indirect negative impact on the interacting species.
Amensalism, parasitism, predation and competition are examples of antagonistic interactions.

2-1/- Amensalism:

Amensalism is a symbiotic relationship between individuals of different species in which one

species get harmed or destroyed while the other either benefits or remains unaffected. It is
considered to be exists between the individuals of two different species, however, it can be
seen within the same species as well.

2-2/- Parasitism:

The term parasite is a Greek word “Parasitos” means one that eats at the table of another. It
can be defined as the relationship between species in which one species benefits from the
interactions at the expense of the other, often without killing the host species.
Mouloud Mammeri University Communication and expression techniques II
Biological and Agronomic Sciences Faculty L2 Biological Sciences L. SADI

An individual derives the benefit from the interaction is termed as a parasite, while an
individual that is harmed during the interactions is termed as host. Parasites are smaller in size
than their host with high fecundity to ensure their survival; but, unlike predators, parasites do
not kill their host and usually live in or on them for a period of time. Parasite lives in
association with the host to use it as habitat and a source of nourishment.

2-3/- Predation:

Is an antagonist relationship as predators gain energy, while the prey suffers. It can be defined
as an act of capturing, killing and eating of one organism by another for obtaining
nourishment. Predators are highly specialised organisms with keen senses that allow them to
capture their prey. The most common type of predation can be seen between two species from
different trophic levels in the levels in the food chain. A competition between predators may
develop in a complex ecosystem where multiple predators feed on the same prey.

3/- Neutral interactions: Neutralism:

In ecology, a relationship exists between two species that interact but do not affect one
another, called as neutralism. It is a form of an interaction in which one species fitness does
not influence the fitness of the other. That means having no or very insignificant effect on
both populations. It differs from mutualism and predation, since one or more species gain
from their interactions.

Neutralism is not same as commensalism, in which one of the species gains profit without
affecting the other interacting species. e.g. Cacti and Tarantulas (species of spider), live
together in the desert without affecting each other.

All life is complex networks of interactions exist in an ecosystem, it is impossible to affirm

that there is o competition or benefit to either species. True neutralism is uncommon or non-
existent, it often used to circumstances where interactions are either insignificant or
negligible. It is almost impossible to demonstrate true neutralism.

Part two: Biodiversity:

Popular interest in protecting biological diversity “which describes amazing range of

species, genetic diversity within each species, and the multitude of earth’s complex biological
communities with their associated ecosystem processes” has intensified during the past few
decades.
Mouloud Mammeri University Communication and expression techniques II
Biological and Agronomic Sciences Faculty L2 Biological Sciences L. SADI

During this time; scientists and the public have recognized that biological diversity
(biodiversity) is being lost at increasing rates. Across the world, human activities are
destroying ecological communities that have developed over millions of years.

Over the next several decades, thousands of species and millions of populations will likely
go extinct. The fundamental driver of all biodiversity losses we are currently witnessing is a
rapidly expanding human population coupled with increased consumptive needs.

In 1850, after roughly 300.000 years of Homo sapiens on the planet, there were around
one billion people on earth. By 1387, not even 140 years later, the world’s human population
has surpassed 5 billion. By 2021, there were 7.9 billion humans globally.

With this many people, the human population grows by tens of millions of people each
year, even with modest population growth. In many parts of the world, this is well beyond the
ecological capacity of the region to support.

To survive and prosper, people use natural resources; they harvest and use oil, water and
wild life products, and convert natural ecosystems for agriculture, cities, roads and industrial
activities. This consumptive, which reduces natural habitat and the associated wildlife
populations, is intensifying because of the demands of a rapidly increasing human population.

Consumption of resources also increases as countries develop and industrialize: the

average citizen of the USA uses five times more resources than the average global citizen, 11
times more than the average Chinese citizen and 32 times more than the average Kenyan
citizen. This growth in the number of humans, together with their ever-more-intensive use of
natural resources, is the fundamental driver behind most current species extinctions.

I/- Definition:

As a distinct scientific field, conservation biology is an integrated, multidisciplinary subject

that developed in response to the challenge of preserving populations, species, ecosystems,
and biological interactions. The main aim of conservation biology is to ensure the long term
preservation of biodiversity. To achieve its aim, conservation biology has set three goals:

 To document Earth’s biological diversity.

 To investigate how humans influence species, evolution and ecosystem processes.
 To investigate practical approaches to protect and restore biological communities,
maintain genetic diversity, and prevent the extinction of species.
Mouloud Mammeri University Communication and expression techniques II
Biological and Agronomic Sciences Faculty L2 Biological Sciences L. SADI

The two first goals describe typical scientific research investigating objective facts. The 3 rd
goal, however, is a part of what makes conservation biology a normative discipline; that is,
conservation biology incorporates human values, not just facts, to understand and achieve its
value-laden goals. In this sense, conservation biology is related to environmentalism, in which
people aim to protect the natural environment for its own sake. However, conservation
biology is at its core a scientific discipline; it is founded on scientific principles.

II/- Biodiversity conservation:

Biodiversity conservation is the protection and management of biodiversity to obtain

resources for sustainable development. It has three main objectives:

 To preserve the diversity of species.

 Sustainable utilization of species and ecosystem.
 To maintain life-supporting systems and essential ecological processes.

III/- Biodiversity and its conservation methods:

It refers to the variability of the life on Earth, it can be conserved in the following ways:

III-1/- In-situ conservation:

Is the conservation of species within their natural habitat. In this method, the natural
ecosystem is maintained and protected. The in-situ conservation has several advantages:

 It’s a cost-effective and convenient method of conserving biodiversity.

 A large number of living organisms can be conserved simultaneously.
 Since the organisms are in a natural ecosystem, they can evolve better and can easily
adjust to different environmental conditions.

Certain protected areas where in-situ conservation takes place include national parks, wildlife
sanctuaries and biosphere reserves.

 National parks: these are small reserves maintained by the government, its
boundaries are well demarcated and human activities such as grazing, forestry, habitat
and cultivated are prohibited.
 Wildlife sanctuaries: these are the regions where only wild animals are found.
Human activities such as timber harvesting, cultivation, collection of woods and other
Mouloud Mammeri University Communication and expression techniques II
Biological and Agronomic Sciences Faculty L2 Biological Sciences L. SADI

forest products are allowed there as long as they do not interfere with conservation
project; also tourists visit these places for recreation.
 Biosphere reserves: are multi-purposes protected areas where the wildlife, traditional
lifestyle of the inhabitants and domesticated plants and animals are protected. Tourists
and research activities are permitted here.

III-2/- Ex-situ conservation:

It involves the breeding and maintenance of endangered species in artificial ecosystems such
as zoo’s, nurseries, botanical gardens, gene banks....etc. there is less competition for food,
water and space among the organisms. The ex-situ conservation has the following advantages:

The animals are provided with a longer time and breeding activity.

The species bred in captivity can be reintroduced in the wild.

Genetic techniques can be used for the preservation and endangered species.

IV/- Strategies for biodiversity:

 All the varieties of food, timber plants, livestock, microbes and agricultural animals
should be conserved.
 All the economically important organisms should be identified and conserved.
 Unique ecosystems should be preserved first.
 The resources should be utilized efficiently.
 Poaching and hunting of wild animals should be prevented.
 The reserves and protected areas should be developed carefully.
 The levels of pollutants should be reduced in the environment.
 Deforestation should be strictly prohibited.
 Environmental laws should be followed strictly.