Download life in the marine environment some basics of biology

What is Ecology?
 Ecology is the
study of the
interactions of
organisms and
their environment.
The organisms
presence &
activities change
the environment.
Abiotic Factors
 Non living
 Light
 Water
 Temperature
 Nutrients
 Oxygen/Carbon Dioxide
Biotic Factors
 Other organisms
Organization in Ecology
 Organismal ecology is concerned with the behavioral,
physiological and morphological ways in which
individual organisms meet the challenges posed by
physiochemical aspect of the environment. The
organism’s limit of tolerance for environmental
stresses ultimately determine where it can live.
Organization in Ecology
 Population – group of individuals in a particular
geographic area that belong to the same species;
population ecology concentrates mainly on factors
that affect population size and composition
Organization in Ecology
 Communities include all
organisms and
populations of different
species in a particular
area. Analysis at this
level involves the ways
in which predation,
competition and other
interactions among
organisms affect
community structure
and organization.
Organization in Ecology
 Ecosystems are composed of all biotic and abiotic
factors including how energy and nutrients cycle
through the ecosystem.
Population Growth
 Exponential Growth – Fig. 10.2 – predicts unlimited
population increase under ideal condition of
unlimited resources
Population Growth
 Logistic population growth – Fig. 10-4 (red curve) –
assumes that there is a maximum population size that
the environment can support; the carrying capacity.
Growth slows as the population size approached the
carrying capacity.
Population Growth
 What factors can act as limiting factors on population
growth?
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Food
Water
Shelter
Temperature
Light
Competition
Number of organisms
Regulation of Population Size
Competition for Resources
 Competitive exclusion – the concept that if two
different populations of organisms are competing for
the same limited resource, one population will use the
resources more efficiently and have a reproductive
advantage that will eventually lead to the elimination
of the other population. (Fig. 10-5)
Regulation of Population Size
Competition for Resources
Regulation of Population Size
Competition for Resources
 Resource partitioning – the division of environmental
resources by coexisting species populations such that
the niche of each species differs by one or more
significant factors from the niches of all coexisting
populations
Regulation of Population Size
Competition for Resources
Regulation of Population Size
Predation
 Predation affects the numbers of both predator and
prey; many predators concentrate on common species
of prey because it is energy efficient
Regulation of Population Size
Predation
 Co-evolution – mutual influence on the evolution of
two different species interacting with each other and
reciprocally influencing each others adaptations
Regulation of Population Size
Symbiosis – two species that live together in
direct contact; symbiont and host
 Commensalism – one benefits without affecting the
other
Regulation of Population Size
Symbiosis
 Parasitism – symbiont benefits at the expense of the
host
Regulation of Population Size
Symbiosis
 Mutualism – both symbiont and host benefit
Energy Flow & Cycling of Nutrients
 Tropic Structure – different feeding relationships in an
ecosystem that determine the route of energy flow and
the pattern of chemical cycling. Tropic levels are
based on the main nutritional source. Tropic levels
include:
 Producers
 Consumers (primary, secondary, tertiary)
 Decomposers
Energy Flow & Cycling of Nutrients
Trophic Structure
 Producers are autotrophs, organisms that can make
their own food. This is the trophic level that
ultimately supports all other life.
Energy Flow & Cycling of Nutrients
Trophic Structure
 Consumers are heterotrophs, organisms that must
obtain their food by eating autotrophs (primary
consumers) or by eating other consumers
(secondary/tertiary consumers)
Energy Flow & Cycling of Nutrients
Trophic Structure
 Decomposers break down waste products and dead
organisms to release nutrients to primary producers
Energy Flow & Cycling of Nutrients
Trophic Structure
Energy Flow & Cycling of Nutrients
Trophic Structure
 Why are the number of levels in any food chain
limited to 3 to 4 levels?
 Only 10% of the energy in one trophic level is passed to
the next trophic level. The other 90% is used up by
the activities of the organism
Energy Flow & Cycling of Nutrients
Pyramid of Energy
Energy Flow & Cycling of Nutrients
Pyramid of Biomass
Energy Flow & Cycling of Nutrients
Pyramid of Numbers
Energy Flow & Cycling of Nutrients
 Primary productivity is the amount of light energy
converted to chemical energy by autotrophs; this is
expressed as the amount of carbon fixed or the rate of
synthesis of new biomass.
 The total amount of organic carbon manufactured by
primary producers is called the gross primary
production.
 Net primary production is the rate of photosynthesis
minus the rate of respiration.
Energy Flow & Cycling of Nutrients
Cycling of Nutrients
 Biological, chemical, and geological processes move
nutrients among organic and inorganic components.
(Remember matter and energy cannot be created or
destroyed, only changed.)
Energy Flow & Cycling of Nutrients
Water Cycle
Driven by solar energy,
most of the cycle occurs
between the oceans and the
atmosphere through
evaporation and
precipitation. Its
movement
also transfers other
material
in biochemical cycles.
Energy Flow & Cycling of Nutrients
Carbon Cycle
The reciprocal processes
of photosynthesis and
respiration are responsible
for the major
transformations and
movement of carbon
Energy Flow & Cycling of Nutrients
Nitrogen Cycle
Most of the nitrogen
cycling through food
webs is taken up by
photosynthetic organisms
in the form of nitrate.
Most of this comes from
the nitrification of
ammonium that results
from the decomposition
of organic material
Energy Flow & Cycling of Nutrients
Phosphorus Cycle
No atmospheric
component; tends to
cycle locally from the
weathering of rocks.
Ecological Zonation
of the Marine Environment
 Classified on the basis of three physical criteria; light
penetration, distance from the shore and water depth.
These three criteria will determine what type of
communities live in these areas.