ZOL 3702 LEARNING UNIT 1
THE NATURE AND DOMAIN OF ECOLOGY
Textbook reference: Page 3-29 chapter one
Learning outcomes:
Evaluate and discuss definitions of ecology (Kreb’s definition is the most acceptable definition)
Define and describe the study of ecology at organism level
Define and describe the study of ecology at population level (also merological and holological studies)
Define and describe the study of ecology at community level
Define and apply to various given examples, the concepts of proximal causes/ explanations and ultimate
causes/ explanations
WHAT IS ECOLOGY?
The content of this module can be divided into 3 sections:
- Organisms and interactions with abiotic environment, such as environmental conditions, resources
- interactions among organisms themselves
- the nature, function, structure and stability of communities
The word ecology was first used in 1869 by Ernest Haeckel
Ecology according to Kreb is the scientific study of interactions that determine distribution and abundance
of organisms.
The interactions in Kreb’s definition include all the biotic and abiotic factors.
The distribution and abundance of organisms are studied on 3 levels: those of individual organisms,
populations, and communities.
Ecology is a central discipline in biology.
It also deals with manufactured environments and the impact of humankind on the natural world.
Ecology is also applicable in labs and the modeling of ecosystems plays an important role in the
description and simplification of ecosystems.
The benefit of prediction which ecological studies offer is important, for example for the rational
conservation of species or control of pest outbreaks.
Ecology at organism level: ecology is the study of how organisms are affected by their biotic and abiotic
environments.
Ecology at population level: ecology is the study of the occurrence or absence of certain species , their
numbers, tendencies and fluctuations in their numbers.
There are two approaches to the study of populations or communities:
1. The merological approach: a study of how individual organisms contribute to determine the character of
the population. It is therefore a study of the components of the population.
2. The holological approach: to study the contribution of the population itself, and the interaction of the
population with the environment.
Ecology at community level: at community level ecology deals with the composition and structure of
communities and the parts that energy and other chemical substances take through the community.
The following form part of all levels of ecology:
- explanations and the understanding of certain tendencies, the pursuit of knowledge
- The description of objects or problems
- prediction, which leads to controls and effective utilization, eg. insect pests and their control and the
conservation of rare species
THE NATURE AND DOMAIN OF ECOLOGY
Textbook reference: Page 3-29 chapter one
Learning outcomes:
Evaluate and discuss definitions of ecology (Kreb’s definition is the most acceptable definition)
Define and describe the study of ecology at organism level
Define and describe the study of ecology at population level (also merological and holological studies)
Define and describe the study of ecology at community level
Define and apply to various given examples, the concepts of proximal causes/ explanations and ultimate
causes/ explanations
WHAT IS ECOLOGY?
The content of this module can be divided into 3 sections:
- Organisms and interactions with abiotic environment, such as environmental conditions, resources
- interactions among organisms themselves
- the nature, function, structure and stability of communities
The word ecology was first used in 1869 by Ernest Haeckel
Ecology according to Kreb is the scientific study of interactions that determine distribution and abundance
of organisms.
The interactions in Kreb’s definition include all the biotic and abiotic factors.
The distribution and abundance of organisms are studied on 3 levels: those of individual organisms,
populations, and communities.
Ecology is a central discipline in biology.
It also deals with manufactured environments and the impact of humankind on the natural world.
Ecology is also applicable in labs and the modeling of ecosystems plays an important role in the
description and simplification of ecosystems.
The benefit of prediction which ecological studies offer is important, for example for the rational
conservation of species or control of pest outbreaks.
Ecology at organism level: ecology is the study of how organisms are affected by their biotic and abiotic
environments.
Ecology at population level: ecology is the study of the occurrence or absence of certain species , their
numbers, tendencies and fluctuations in their numbers.
There are two approaches to the study of populations or communities:
1. The merological approach: a study of how individual organisms contribute to determine the character of
the population. It is therefore a study of the components of the population.
2. The holological approach: to study the contribution of the population itself, and the interaction of the
population with the environment.
Ecology at community level: at community level ecology deals with the composition and structure of
communities and the parts that energy and other chemical substances take through the community.
The following form part of all levels of ecology:
- explanations and the understanding of certain tendencies, the pursuit of knowledge
- The description of objects or problems
- prediction, which leads to controls and effective utilization, eg. insect pests and their control and the
conservation of rare species
