NOTES

MOKALA PRIMARY SCHOOL

NATURAL SCIENCE NOTES 2016


TERM 1: CHAPTER 1: THE BIOSPHERE

Notes: The Biosphere

What Is Ecology?

1. Ecology comes from the Greek words oikos (house or place where one lives) and logos (the study of).
2. Ecology then means the study of the house in which we live (the study of our environment...where we live).
3. Ecology can be defined more specifically as the study of the interactions between organisms and the nonliving components of their environment.
4. The Earth includes a tremendous variety of living things. Each organism depends in some way on other living and nonliving things in its environment.
5. Ecology involves collecting information about organisms and their environment, looking for patterns, and seeking to explain these patterns and interrelationships.

Levels Of Organization

1. Biosphere: The surface of the Earth as a whole is an ecosystem. We call the surface of the Earth the biosphere. The Biosphere is the surface of the Earth (air, water, and land) where living things exist. Ecologists study the biosphere because all organisms must share the biosphere and ecologists must understand how they interact individually and collectively.

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2. The three basic approaches scientists use to conduct modern ecological research are:

a. Interactions within populations

b. Individual interaction within communities

c. interactions among living things and abiotic factors.

• An ecologist may want to examine how different components interact within a controlled environment so laboratory experiments are set up.
• Many ecological phenomena are difficult to study because the environment is always changing, sometimes unexpectedly, and ecologists may have a hard time determining which factor caused a specific observation.
• Ecologists make models to represent environments or organisms to examine or demonstrate a specific characteristic.
• Sometimes mathematical formulas are developed to interpret results and predict outcomes.

3. Ecosystems: The Biosphere is composed of smaller units called ecosystems.

Biotic and Abiotic Factors: Within an ecosystem, two types of environmental factors can be found:

• biotic factors: all the living organisms
• abiotic factors: the nonliving factors

 An ecosystem includes all the organisms and the nonliving environment found in a particular place.Ecosystems can be as large or as small as we decide. Any area you decide to study can be considered an ecosystem. For example you may choose to study your back yard, Chattahoochee National Forest, Lake Lanier or a wild life refuge. Any of these would be considered an ecosystem.Ecosystems are very complex. They can contain hundreds or even thousands of interacting species.

1. Each organism or species in the community has a ROLE or PROFESSION in that community and in ecology--this is the organism's NICHE.
2. A species niche is its way of life, or the role the species plays in its environment.
3. The niche includes the range of conditions that the species can tolerate, the methods by which it obtains needed resources, the number of offspring it has, its time of reproduction and all its other interaction with its environment.
4. The FUNDAMENTAL NICHE is the range of conditions that a species can potentially tolerate and the range of resources it can potentially use.
5. The REALIZED NICHE of a species is the range of resources it actually uses.
6. GENERALISTS are species with broad niches; they can tolerate a range of conditions and use a variety of resources. Opossums are generalists.
7. Species that have narrow niches, such as the koala, are called SPECIALISTS.

4. POPULATION: includes all the members of the same species that live in one place at one time. For example, a population of Rana pipiens (green grass frogs) or a population of Rana catesbeiana (bullfrogs).

5. COMMUNITY: Populations are individual species,but all the interacting organisms (all the different populations) that live in a particular area make up the community. Community interactions, such as competition, predation, and various forms of symbiosis, can powerfully affect an ecosystem.

• Competition occurs when the organisms of the same or different species attempt to use an ecology resource in the same place at the same time.
• Predation is an interaction in which one organism captures and feeds on another organism. The organism doing the capturing is called the predator and the organism being captured is called the prey.
• Symbiosis is any relationship where two species share some sort of relationship. There are 3 types:
• mutualism,
• commensalism and
• parasitism.

Mutualism a symbiotic relationship where both species benefit; think of it as a help-help relationship.

Clownfish swimming among sea anemone tentacles

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Commensalism a symbiotic relationship in which one member benefits and the other member is unaffected; think of it as a help-unaffected relationship

Remoras with a Nurse Shark (Wikipedia)

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Parasitism a symbiotic relationship in which one member benefits and the other member is harmed; think of it as a help-hurt relationship; the member benefiting is the parasite and the member being harmed is the host.

The parasites on this grouper are isopods. (Courtesy of the Sanctuary Collection, NOAA)

6. HABITAT: The physical location of a population or community of organisms

 

Habitat for a community of fish

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7. ORGANISM: The simplest level of organization in ecology is that of the single individual is known as an organism

8. DIVERSITY: a measure of the number of different species in an ecosystem and how common each species is.