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ECOLOGICAL ORGANIZATION
1.
2.
3.
4.
5.
Population
Community
Ecosystem
Biome
Biosphere
COMMUNITY AND POPULATION ECOSYSTEM
All the populations of different organisms within a given
area make up the community.
Ex: All of the populations in ODTÜ forest
The two factors that make up the environment of an organism:
BIOTIC FACTORS
• It includes all the
living organisms in
the environment.
ex: Producers
Consumers
Decomposers
ABIOTIC FACTORS
•
•
•
•
•
•
•
Light
Heat or solar energy
Water
Minerals
Soil
Oxygen
Wind etc.
Predator
Any organism that catches
and kills other organisms.
Prey
Organism that is actively
captured and used as food
by predators.
Predator-Prey Relationship
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Interspecific competition
It occurs when two
species attempt to
utilize the same
source when there is
not enough of the
source to satisfy
both.
***Interspecific
competition occurs
when the niches of
two species overlap.
Intraspecific competition
Intraspecific competition is a particular form of
competition in which members of the same species
compete for the same resource in an ecosystem (e.g.
food, light, nutrients, space).
Symbiotic Relationships
PARASITISM: Ectoparasites
leech
lice
tick
Symbiotic Relationships
PARASITISM: Endoparasites
Bacteria
HIV and other viruses
Tapeworm in human
intestine
Symbiotic Relationships
COMMENSALISM:
Small fish living with sharks eat the food particles left
over from the sharks feeding
Symbiotic Relationships
COMMENSALISM:
Sea anemone
(deniz gülü) and
certain fishes
which gain
portection
Symbiotic Relationships
MUTUALISM:
Nitrogen fixing bacteria living in
the root nodules of legumes
Ants and aphids
Symbiotic Relationships
MUTUALISM:
food and O2
Lichen
Fungus + Algae
CO2 , H2O, protection,
moisture, attachment
site
Symbiotic Relationships
PROTO-COOPERATION:
Food and distribution
Crab
+
sea anemone
Protection with tentacles
Symbiotic Relationships
PROTO-COOPERATION:
Oxpeckers and grazing
animals
Ecological Succession
Although ecosystems appear
stable, they do undergo
change. Some of the changes
tend to make the environment
more suitable for new types of
organisms.
Thus, the original organisms
in an ecosystem are slowly
replaced by other types. Over
time, communities replace
each other
The process by which an existing community is slowly
replaced by another community is called ecological
succession.
Ecological Succession
Succession of one community by another goes on until a
mature, stable community develops. Such a community is
called a climax community.
In an ecosystem with climax community, the conditions
continue to be suitable for all members.
The climax community remains until an event such as, fire,
flood, or volcanic eruption.
After the destruction of climax community, succession
begins again and continues until a new climax community
develops.
Ecological Succesion
When succession occurs in an area that has no
existing life, for example bare rock, it is called primary
succession.
Ecological Succesion
Succession that occurs in an area in which existing
community has been partially destroyed and its
balance upset is called secondary succession.
Ecological Succession
POPULATIONS
Population: A group of organisms of the same
species living together in a given area or
volume.
Ex: Human population in Ankara
POPULATIONS
Population growth; is the change in the number of
individuals within a population.
Population growth is a function of number of birth,
death, immigrations and emigrations.
The population growth rate, abbreviated “r” is the
change in population size per individual per unit time:
Change in number of individuals per unit time
r =
Total number of individuals at the beginning of time interval
POPULATIONS
Density of population: The number of individuals in
a unit area or volume.
Ex: number of human in 1 km2
Carrying capacity: The maximum size of a
population that can be supported by an environment.
This upper limit is set by the particular resource that is
short in supply.
Ex: The carrying capacity of algae in a pond may be
set by the concentration of phosphate.
The carrying capacity of wolves may be set by the
availability of elks.
POPULATIONS
A population that exceeds its
carrying capacity, with more
individuals than the
environment can support, will
return to its carrying capacity
as it experiences lower birth
rates and greater death rates.
A population below its carrying
capacity will reach its carrying
capacity as it experiences
higher birth rates and lower
death rates.
POPULATIONS
Size of the Population:
1. The size of the population is determined by birth rate
and death rate
Birth rate: X
Death rate: Y
If
X
> Y
population increases
If
X
< Y
population decreases
If
X
= Y
population is almost stable
2. Immigration and emigration also effects the population
size.
Population size = (Birth rate +immigration) - (Death rate + emigration)
LIMITING FACTORS FOR POPULATION
GROWTH AND SIZE
1. LIMITING FACTORS:
a) EXTERNAL FORCES
b) INTERNAL FORCES
*amount of food
*instinct
*migration
*social behavior
*epidemics
*birth control
*war
*the ability to reproduce
*temperature
*soil
*amount of oxygen
*moisture
LIMITING FACTORS FOR POPULATION
GROWTH AND SIZE
2. LIMITING FACTORS
a) DENSITY-DEPENDENT:
Competition: If two populations compete for the
same limiting factor, the competition may become a
limiting factor.
Ex: The competition of two dogs for a piece of bone
is intraspecific competition but the competition of
a dog and a cat for a piece of meat is interspecific
competition.
Interspecific competition
LIMITING FACTORS FOR POPULATION
GROWTH AND SIZE
Predation: In predator-prey relationship, each
population continually determines the size of
the other.
number of
prey in an
area
increases
number of
predators
increase
as the
predators feed
on the prey,
the number of
prey begins to
decrease
number of
predators
also decrease
because of
the decrease
in their food
supply
LIMITING FACTORS FOR POPULATION
GROWTH AND SIZE
Parasitism: If the number of parasites carried by the host
is increased, the host will die, this condition decreases
the number of population members.
Space-food: Space is generally more important for plant
populations because they take their nutrients and water
from the soil.
Since animal can move, the space limits the population
after food, disease and predators.
Diseases: Population density is also related with
diseases
Ex: Malaria, the denser human population, the greater
chance of disease being passed to others
LIMITING FACTORS FOR POPULATION
GROWTH AND SIZE
2. LIMITING FACTORS
b) DENSITYINDEPENDENT:
Natural disasters such
as earthquakes,
hurricanes, flood
cause decrease in the
number of populations.
THE GRAPHS OF POPULATION GROWTH
1. THE S -GRAPH
no. of
individuals
I
II
III
IV
time
I. Initial Growth:
At the beginning
there are not much
individuals in the
population
(adaptation time for
the environment)
II. Exponential
Growth:
Population
grows rapidly.
The birth rate
is greater than
the death rate.
III. Negative
Growth:
Increase in
the
environmental
resistance
causes a
decline in the
population
size.
IV. Stationary
state: the birth rate
and death rate are
almost equal.
THE GRAPHS OF POPULATION GROWTH
2. THE J -GRAPH
no. of individual
After the initial growth, the
density of population increases
logarithmically.
But, when the environmental
resistance occurs, the size of
the population decreases
sharply.
In this growth graph there is no
stationary state, there is a
time stability time.
HYPOTHESIS ABOUT POPULATIONS
1. Thomas Maltus Hypothesis (1)
Food, diseases, space, wars
and natural disasters control
the growth of a population.
no. of individual
Mainly increase in the death
rate stabilizes the population.
time
HYPOTHESIS ABOUT POPULATIONS
1. Thomas Maltus Hypothesis (2)
The number of individuals in
the human population
increases logarithmically but
the food supply increases
arithmetically.
Numerical increase
no. of
individuals
Amount
of food
So, the growth of the
population depends on the
food supply.
time
HYPOTHESIS ABOUT POPULATIONS
2. Wynne – Edward Hypothesis
The growth of the population is
controlled by instinct
behaviors.
no.of individuals
Mainly, decrease in the birth
rate controls the population
size.
inner forces
time
AGE DISTRIBUTION IN HUMAN POPULATIONS
AGE DISTRIBUTION IN HUMAN POPULATIONS
If the number of young individuals is greater
than the number of middle-aged or older
individuals, then this population is said to be a
growing population.
***If the number of elderly individuals is
greater than the number of young ones, the
population is said to be getting smaller.
If the number of young
and elderly individuals
are equal, then the
population is said to be
a stable population.
EXPERIMENTS ABOUT POPULATIONS
J. Emlen and his colleagues did some experiments with mice populations.
I.
The amount of food is constant
Population size is increased
The amount of food becomes insufficient
Emigration starts
Population size becomes stable
RESULT: Emigration
causes the stabilty of
the population.
EXPERIMENTS ABOUT POPULATIONS
ll.
The amount of food is constant
Population size is increased
The amount of food becomes insufficient
Emigrations is not allowed
RESULT: Food affects the
Birth control starts
Population size becomes stable
rate of birth and emigration
from the population. But in
two circumstances the aim
is to maintain the size of the
population.
EXPERIMENTS ABOUT POPULATIONS
lll.
The amount of food is increased day by day
Population size is increased
Emigration is not allowed
RESULT: Although the
food is enough but space will
determine the size of the
population.
Space becomes insufficient
Birth rate decreases and death rate increases
Population size becomes stable
FACTORS THAT CAUSE EXTINCTION OF SPECIES
Habitat destruction
Competition
Predation
Disease
Coextinction
Global warming
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Türkiyede Nesli Tükenmekte Olan
Hayvanlar
Asya aslanı (Panthera leo persica)
Kafkas öküzü (Bison bonasus
caucasicus)
Çita (Acinonyx jubatus raddei)
Kelaynak
Deniz kaplumbağaları
Akdeniz foku (Monachus monachus)
Telli turna (Anthropoides virgo)
Ceylan (Gazella gazella)
Yırtıcı kuşlar
İç su balıkları
Dağ horozu
Van kedisi
Dünyada Nesli Tükenmekte
Olan Hayvanlar
Panda (Bambu Ayısı)
Kutup Ayısı
Penguenler
Kısa Gagalı Yunus
Su samurları
BIOMES
The term biome refers to a large geographical region that
has a particular climax community. In terrestrial biomes,
climax community is the dominant plant population.
BIOMES (Decidious Forest)
Dominant vegetation is trees such as oak, maple,
chestnut, smaller trees and shrubs.
Rainfall avarages between 75-150 centimeters a year.
 Summers are usually hot and humid, and the winters are
cold.
BIOME (Grassland)
Grassland:
Grasses are the dominant vegetation
Found in North America, Asia, South America,
Europe and Africa
Rainfall ranges from 25-75 centimeters a year.
BIOME (Desert)
Desert
Rainfall is less than 25 centimeters in one year.
Found in America, Africa, Asia and Australia
Temperatures vary widely between night and day
Usually don’t have any vegetation, but on some cacti, yucca and
bushes are found.
Desert animals are usually active at night
BIOMES (Freshwater Biomes)
BIOMES (Marine Biomes)
Atatürk’ün Çevreye Verdiği Önem
Atatürk bir gün Yalova’daki yazlık
köşküne gider. Köşkün yanında bulunan
ulu çınar ağacının dallarını kesmeye
çalışan bahçıvanı görür ve derhal
müdahale ederek, ağacın dallarını
neden kestiğini sorar. Bahçıvanın,
ağacın dallarının uzayıp, köşkün
duvarına dayandığını ve köşke zarar
vereceğini ve bu yüzden kesmek
istediğini söylemesi üzerine Atatürk,
herkesi şaşırtan ve hayrete düşüren bir
emir verir. Buna göre, ağacın dalları
kesilmeyecek bina kaydırılacaktır.
Görev, İstanbul Belediyesi Fen İşleri
Yollar-Köprüler Şubesine verilir. Köşkün
temeline kadar toprak kazılarak, bina
İstanbul’dan getirilen tramvay raylarının
üzerine oturtulur ve raylar üzerinde
kaydırılarak, çınar ağacından 4.80m.
uzaklaştırılır.