Organism and population:
Ecology- study of interaction biotic and abiotic –
Levels of ecology – Organism-lowest level (migration, suspension, adaptation) – Population
(birth rate, death rate, age distribution, sex ratio)- community (food chain, food web)- biome-
Population- same species, common geography, share or compete for resources, can interbreed
Ecologist consider product of both sexual and asexual as population
Attributes to describe population – Birth rate – number of birth per capita (0.2 individual /rose
/ year)
Death rate- Number of death per captia (0.1 individual/fruit fly/week)
Age distribution- number of female per capita male
Age distribution- Pre reproductive (0-15yr) reproductive (15 to 50 yr) post reproductive (50
onwards)
Expanding (Pre R>R>Post R) Stabilizing (Pre R = R > Post R ) Declining (R>Pre R=Post R )
Population density(N)- best method to count number , not possible to count number(bacteria
colony is counted), relative population density( single catch fish number ) Indirect method (tiger
by pug marks and fecal pellet )
Population Growth- Depend on resources, predation pressure and adverse weather, after time
‘t’ population is Nt =N0 + (B-natality +I immigration)- (D mortality +E Emigration) normal
population mainly difference of natality and mortality important.
Population growth model: -
Model Exponential Logistic
Condition Resources unlimited (food and space) Resources limited
Shape J-shape Sigmoid (lag, exponential and
stationary phase
Equation dN/dt = rN r =biotic potential (b-d) rate of dN/dt = rN(K-N/K) K = carrying
natural increase Nt = N0ert capacity – maximum number of
population density supported by
resource
Special point Large animal can grow exponential if When K>> N → population can
resource is unlimited grow exponential dN/dt = rN
King and minister story of grain When K=N, curve asymptote,
dN/dt=zero
Then N= constant
, Types of Small size, more progeny – r-selected Large size, less progeny – k-
species selected
Population interaction
Predation: (+,0)- predator behavior prudent – not kill all prey at a time
Example Tiger eating deer Bird eating seed Cattle eating grass
Role Flow of energy-food Control population of Maintain biodiversity-
chain prey- prickly pear predator reduce competition
cactus introduced into - Pisaster important predator
Australia controlled by in pacific coast- when
predator moth removed ,10 invertebrate
extinct
Animal →Mimicry Plant adaptation →25 percent insect
adaptation →Camouflage-prey phytophagous, plant can’t run
to avoid blend with (1) Morphological adaptation
predation surrounding -thorns in acacia and cactus
→poisonous prey- →Biochemical - nicotine,
monarch butterfly, caffeine, quinine, strychnine,
acquire poison when opium -not eaten by grazer
larvae feed on →Calotropis – produce
poisonous weed cardiac glycoside -poisonous
Competition (-,-)
Definition two closely Not necessary competition Not necessary
related species occur between closely competition
compete for related Species-(visiting occur between
limited resources flamingo compete for limited resources
zooplankton with small fish)
interference Goat presence Gause competitive exclusion two species
competition Abingdon tortoise means - competing can
extinct in not co-exist
Galapagos Island indefinitely ,one
has to extinct)
New definition One species competitive release- Balanus-superior,
decreases ‘r’ of presence of superior Cathamalus -
each other – few species, inferior species inferior barnacle
evidence distribution limited
How to avoid resource different time or mode of Mac- arther
competition partitioning feeding, warbler- five
species –
Ecology- study of interaction biotic and abiotic –
Levels of ecology – Organism-lowest level (migration, suspension, adaptation) – Population
(birth rate, death rate, age distribution, sex ratio)- community (food chain, food web)- biome-
Population- same species, common geography, share or compete for resources, can interbreed
Ecologist consider product of both sexual and asexual as population
Attributes to describe population – Birth rate – number of birth per capita (0.2 individual /rose
/ year)
Death rate- Number of death per captia (0.1 individual/fruit fly/week)
Age distribution- number of female per capita male
Age distribution- Pre reproductive (0-15yr) reproductive (15 to 50 yr) post reproductive (50
onwards)
Expanding (Pre R>R>Post R) Stabilizing (Pre R = R > Post R ) Declining (R>Pre R=Post R )
Population density(N)- best method to count number , not possible to count number(bacteria
colony is counted), relative population density( single catch fish number ) Indirect method (tiger
by pug marks and fecal pellet )
Population Growth- Depend on resources, predation pressure and adverse weather, after time
‘t’ population is Nt =N0 + (B-natality +I immigration)- (D mortality +E Emigration) normal
population mainly difference of natality and mortality important.
Population growth model: -
Model Exponential Logistic
Condition Resources unlimited (food and space) Resources limited
Shape J-shape Sigmoid (lag, exponential and
stationary phase
Equation dN/dt = rN r =biotic potential (b-d) rate of dN/dt = rN(K-N/K) K = carrying
natural increase Nt = N0ert capacity – maximum number of
population density supported by
resource
Special point Large animal can grow exponential if When K>> N → population can
resource is unlimited grow exponential dN/dt = rN
King and minister story of grain When K=N, curve asymptote,
dN/dt=zero
Then N= constant
, Types of Small size, more progeny – r-selected Large size, less progeny – k-
species selected
Population interaction
Predation: (+,0)- predator behavior prudent – not kill all prey at a time
Example Tiger eating deer Bird eating seed Cattle eating grass
Role Flow of energy-food Control population of Maintain biodiversity-
chain prey- prickly pear predator reduce competition
cactus introduced into - Pisaster important predator
Australia controlled by in pacific coast- when
predator moth removed ,10 invertebrate
extinct
Animal →Mimicry Plant adaptation →25 percent insect
adaptation →Camouflage-prey phytophagous, plant can’t run
to avoid blend with (1) Morphological adaptation
predation surrounding -thorns in acacia and cactus
→poisonous prey- →Biochemical - nicotine,
monarch butterfly, caffeine, quinine, strychnine,
acquire poison when opium -not eaten by grazer
larvae feed on →Calotropis – produce
poisonous weed cardiac glycoside -poisonous
Competition (-,-)
Definition two closely Not necessary competition Not necessary
related species occur between closely competition
compete for related Species-(visiting occur between
limited resources flamingo compete for limited resources
zooplankton with small fish)
interference Goat presence Gause competitive exclusion two species
competition Abingdon tortoise means - competing can
extinct in not co-exist
Galapagos Island indefinitely ,one
has to extinct)
New definition One species competitive release- Balanus-superior,
decreases ‘r’ of presence of superior Cathamalus -
each other – few species, inferior species inferior barnacle
evidence distribution limited
How to avoid resource different time or mode of Mac- arther
competition partitioning feeding, warbler- five
species –
