Principles of Population EcologyJuan Francisco García

4TH MYPBiology

ECOLOGY AND ECOSYSTEMS

Ecosystems are made up of the interactions between the living and non-living components within them.

THE COMPONENTS OF

AN ECOSYSTEM

Living biological factors that influence the other organisms or environment of an ecosystem.

This is a lot more than just listing the plants, animals or micro-organisms found in an ecosystem. It includes the roles played by the organisms.

BIOTIC FACTORS

Biotic factors interact

as:

Producers

Consumers

Detrivores

Decomposers

Parasites

HostPredator

Competitor

Herbivore

Symbiant

Pathogen

The Physical and Chemical components of an ecosystem.

ABIOTIC FACTORS

The Atmosphere

Climate and Water

Soil Structure and Chemistry

Water Chemistry

Seasonality

It is the abiotic conditions in an environment which ultimately give rise to the biotic community present.

This is illustrated below with examples of six different ecosystems, including an ecosystem found on the surface of some rocks, each of which is the result of the initial controlling abiotic factors which operate.

EXAMPLES

ALPINE MEADOW

ACIDIC HEATH

DECIDUOUS WOODLAND

MAQUIS OR CHAPARRAL

LICH

EN O

N A

RO

CK F

ACE

SAND DUNES

The position that an organism occupies in a food chain, or a group of organisms in a community that occupy the same position in food chains.

TROPHIC LEVELS

FOOD CHAINS AND FOOD WEBS

FOO

D W

EB

PYRAMID OF NUMBERS

PYRAMID OF BIOMASS

PYRAMID OF PRODUCTIVITY

/ ENERGY

ECOLOGICAL PYRAMIDS

SPECIES, POPULATION, HABITATS AND NICHES

Group of organisms that interbreed and produce fertile offspring.

If 2 species breed together to produce a hybrid, this may survive to adulthood but cannot produce viable gametes and so is sterile.

SPECIES

The Species concept cannot:

Identify whether geographically isolated populations belong to the same species.

Classify species in extinct populations.

Account for sexually reproducing organisms.

Clearly define species when barriers to reproduction are incomplete.

Is defined in ecology as:

A group of organisms of the same species living in the same area at the same time, and which are capable of interbreeding.

POPULATION

It refers to the environment in which a species normally lives.

HABITAT

An ecological niches is best be described as where, when and how an organism lives.

No two different species can have the same niche because the niche completly defines a species.

NICHE

Is a group of populations living and interacting with each other in a common habitat.

COMMUNITY

Is a community of interdependent organisms (the biotic component) and the physical environment (the abiotic component) they inhabit.

ECOSYSTEM

Biotic components

Abiotic components Ecosystem

ECOSYSTEMS INTERACTIONS

ONE WITH THE ENVIRONMENT…

Crypsis: is the ability of an organism to avoid observation or detection by other organisms.

ONE WITH THE ENVIRONMENT…

Camouflage: is the ability of an organism to modify their structure, texture or color to resemble the environment and avoid being notice.

ONE WITH THE ENVIRONMENT…

Mimetism: is the similarity of one species to another which protects one or both.

Batesian Mimetism: to resemble dangerous species.

Mullerian Mimetism: they have an awful taste.

ONE WITH THE ENVIRONMENT…

Aposematism: is the ability of some organisms to present colorful or very visible warning to help avoid predators.

SYMBIOSIS

“The life in conjuction of two different organisms, normally in close association, and, ussually, with at least one of them being benefit.”

-Anton de Bary-

TYPES OF SYMBIOSIS

Ectosymbiosis: the symbiont lives over the body of the host, including the interior of the digestive track and the endocrine glandules.

Endosymbiosis: the symbiont lives inside the cells of the host or in the intercellular space.

PARASITISM

«The success of parasitism [also symbiosis] is well placed in adaptation and survival, it means that the success is measured not by the damage that is causes, but by the capacity to adapt and integrate the

environment.»

-Sanchez, 2008-

COMENSALISM

One of the species gets a benefit while the other does not.

TYPES OF COMENSALISM

Foresis: It`s when an organism use the other as a way of transport.

Inquilinism: When an organism use another one as refuge or habitat.

Metabiosis or Tanatocresis: it´s a more indirect relation, when one organism use something from the other, after it dies.

MUTUALISM

“Interaction between individuals of different species, in which both obtain a benefit and change their biological aptitude.

PREDATION

“It´s a type of interspecific relation, which consist on the hunt and death that some

species suffer (prey), by the means of other organisms, called predators. The same individual can be prey and predator, according to the situation.

COEVOLUTION

“It´s described as the mutual evolutive adaptation phenomena produced between two or more species as the result of both sides influence by different interactions of life.”