2. Introduction
◦ Ecology is the scientific study of how living things interact with each other and their natural
environment.
◦ The Word Ecology is the combination of two Greek words; “Oikos” which means, Home and the
“Logos” which means Knowledge or study.
◦ Ecology is relationships of living organisms with their environment from various perspectives
4. Population ecology
It deals with studies of structure and dynamics of populations. That is
that affect population and how and why a population varies over time. A
population ecologist studies the interrelations of organisms with their
environments properties of populations rather than the behavior of the
individual organisms.
Among the properties of population studied is population size, population
density, patterns of dispersion, demographics, dynamics, population growth
and restraints on growth.
5. Organism /physiological/ behavioral ecology
It focuses on how the living organisms (animal and plants) react to biotic and abiotic factors in
their environment; physiology, morphology and behavior. Physiological ecology on animal
on the whole-animal function and alteration to ever-changing
environment.
The physiological processes studied are temperature regulation,
nutrition, water and metabolism on energy and energetic and
response to environmental stresses. These environmental factors
may include nutrition, disease, climate variation and toxic exposure.
6. Community Ecology
This deals with the interactions between organisms that is, the feeding
relationships among species
Community ecologist investigates the factors influencing community
structure, biodiversity, and the distribution and abundance of species. These
factors include the interrelations with the non living world and different
collections of interrelations that take between species. The primary focus of
community ecology is on predation, herbivory, competition and parasitism
and mutualism.
7. Ecosystem Ecology
Ecosystem is a community of living organism that is, animals, plants and
microbes together with abiotic components of their environment (such
components include things like water, air and mineral soil) interrelating g as
system.
The studies of ecosystem includes the study of certain processes that link
living (biotic components) to the non-living (abiotic components). These
components are said to be joined together via nutrient sequences and
flows.
8. Ecological concepts
concept 1:
Levels of biological organization (genes, populations, species, communities, ecosystems,
landscapes, regions)=
The cross-scale nature of ecosystems includes ecological processes that operate from
centimeters and days to hundreds of kilometers and millennia and collectively affect
biodiversity. In a forest, for example, this ranges in increasing scale from physiological
processes that affect the life history of leaves, competition between plant species in a
clump or gap that affect populations, disturbance and predation processes that influence
the composition and structure of a community, to climatic processes that influence
landscapes and regions
9. concept 2
Native species= are those that naturally exist at a given location or in a
particular ecosystem – i.e., they have not been moved there by humans.
For example, cedar and salmon are native to B.C.; Scotch broom and brown
bullhead are introduced species that are not native to B.C. and have
invaded some local ecosystems. Native plants, animals, fungi and microbes
co-evolved over time to form a complex network of relationships. They are
the foundation of natural ecosystems that sustain biological diversity.
10. concept 3
A keystone species, ecosystem or process= has a disproportionate influence on
an ecosystem or landscape such as the role beavers play in altering the
hydrological characteristics of streams and wetlands. Keystone species have
effects on biological communities that are disproportionate to their abundance
and biomass. The loss of keystone species results in broader community or
ecosystem-level effects.A keystone species interacts with other species through
predation, symbiotic dependencies such as plant-pollinator relationships, or
ecosystem modification
11. concept 4
Population viability/thresholds=“Viability” in this context refers to the
probability of survival of a population/species in the face of ecological
processes such as disturbance. When the amount of habitat available
declines below the “extinction threshold”, a population/species will decline
and eventually disappear;in addition to habitat for particular populations, a
species’ survival depends on maintaining healthy genetic variability.
12. concept 5
Ecological resilience= is the capacity of an ecosystem to cope with
disturbance or stress and return to a stable state. The concept of ecological
resilience is consistent with the notion that ecosystems are complex,
dynamic and adaptive systems that are rarely at equilibrium; most systems
can potentially exist in various states. Moreover, they continually change in
unpredictable ways in response to a changing environment.This concept
measures the amount of stress or disruption required to transform a system
that is maintained by one set of structures and processes to a different set
of structures and functions
13. concept 6
Disturbances= are individually distinct events, either natural or
human-induced, that cause a change in the existing condition of an
ecological system. Disturbances can be described in terms of their
type, intensity, spatial extent, frequency and other factors. •Natural
disturbances include wildfire, flood, freshet, lake turnover,
drought, windthrow, and insect and disease outbreaks. Some “natural
disturbances” may be responding to human-caused climate change.
14. concept 7
Connectivity/fragmentation= is the degree to which ecosystem structure
facilitates or impedes the movement of organisms between resource
patches. What constitutes connectivity is scale-dependent and varies for
each species depending on its habitat requirements, sensitivity to
disturbance and vulnerability to human-caused mortality. Connectivity
allows individual organisms to move in response to changing conditions,
such as seasonal cycles, a forest fire or climate change.
