# The interaction of life: EcologyIntroduction to Ecology: Population Ecology

Posted on February 23, 2009

>Learning Objectives:
Define ecology and distinguish among the following ecological levels: population, community, ecosystem, landscape, and biosphere.
Define population density and dispersion and describe the main type of population dispersion.
Explain the four factors (natality, mortality, immigration and emigration) that produce changes in population size and solves simple problems involving this changes.
Define intrinsic rate of increase and explain the J-shaped growth curves (exponential population growth).
Planet bumi
Biological organizations: hierarchical functional structure
Populasi
Komunitas
Ekosistem
Lanscape
Biome
Ekosfer (Biosfer)
Population Ecology

Population properties:
Population density
Population dispersion
Population size

Introduction
Ecology: the science that studies interactions among organisms (biotic factors) and between organisms and their non living physical environment (abiotic factors: water, temperature, pH, wing, chemical nutrient).
Abiotic factors: Earth scinece, geology, chemistry, oceanography, climatology, and meteorology
Mathematical models describe population growth:
On a global scale: 2 factors determine the population size:
natality: the rate at which individuals produce offspring (the average per capita birth rate) : e.g. number of birth per 1000 people per year).
mortality:the rate at which individuals die (the average per capita deah rate): e.g. number of death rate per 1000 people per year.
On a local population size determined by:
the average per capita birth rate (b)
the average per capita death rate (d)
the average per capita immigrant rate (i)
the average per capita emigrant rate (e)
The average growth rate:
N/t = N (b-d)
N: the changes in number of individuals in the population
t : the change in time
N : the number of individuals in the existing population
The growth rate (r) : the rate of change (increase or decrease) of a population on a per capita basis is the birth rate minus the death rate.
r = (b – d)
Global Population
Example: N = 10,000 people, 200 birth rate per year ( 20 birth per 1000 people) and 100 death per year (10 death per 1000 people).
r = 20/1000 – 10/1000
= 10/1000 = 0.001 (1% per year)

Local population:
r = (b– d ) + (i –e)
Example: A population of 10,000 that has 200 birth (20 per 1000), 100 death (10 per 1000), 10 immigrants (1 per 1000), and 100 emigrants (10 per 1000) in a given year.
r = ((0.02 – 0.010) + (0.001 – 0.010)
= 0.001 or 0.1% per year
Instantaneous growth rate:
N/t  dN/dt
dN/dt = rN
solving for N: Nt = No. ert
Nt : number of individuals in at t time
No : number of individuals at the beginning ( t = 0)
r : instantaneous growth rate
e : base of natural logarithms ( 2.71828).
solving for r:
ln Nt – ln No
r = —————-
t
Pertumbuhan Populasi
COMMUNITY ECOLOGY

Learning objectives:
Characterize a community and distinguish between a community and ecosystem.
Define ecological niche, distinguish between an organism’s fundamental niche and its realized niche. and give several examples of limiting resources that might affect an organism’s ecological niche.

Introduction
Community: ?
Community structure : ?
Community functioning
Community ecology:
Ecosystem
Community

Communities contain autotrophs and heterotrophs
Primary producers (autotrophs)
Consumers (heterotrophs)
Primary consumers (herbivores)
Secondary consumers (carnivores)
Tertiary consumers (carnivores)
Omnivores
Detritus feeders (detritivores)
Decomposers (saprotrophs)

Ecosystems and Biosphere
Learning Objectives:
Compare how matter and energy operate in ecosystems.
Summarize the concept of energy flow through a foodweb.
Draw and explain typical pyramids of numbers, biomass and energy.

Introduction
Ecosystems
Biosphere

Ecologists study:
energy flow,
cycling of nutrients,
effects of natural & human induced disturbances

EOLOGY AND THE GEOGRAPHY OF LIFE
Learning objectives:
Define biome and briefly describe the nine major terrestrial biomes, giving attention to the climate, soil and characteristic plants and animals of each.
Describe at least one human effect on each of the biomes discussed.

Introduction
Climate: temperature and precipitation  many different
environments
Natural selection: organism’s to survive and reproduce
abiotic & biotic factors act to eliminate the least-fit
individuals in a given population  better adapted
org.
Biomes are largely distinguished by their dominant form of vegetation.
biome: a large, relatively distinct terrestrial region
characterized by similar climate, soil, plants, and animals regardless of where it occurs.
a number of interacting ecosystems
temperature and precipitation: the most important factors ! (Fig. 54-1, p. 1206).
Near the poles: temperture is the most overriding climate factors.
Temperate & tropical regions: precipitation more significant than temperature (Fig. 54-2, p.1207).
Climate factors to which biomes are sensitive:
tempereture extreems
rapid temperature changes
floods
droughts
strong wind
fires

Charachteristics in terms of:
climate
soil
plants
animals

Nine major biomes:
Tundra
Taiga
Temperate rain forest
Temperate deciduous forest
Temperate grassland
Chapparal
Dessert
Savana
Tropical rain forest
Major Biomes
Tundra Map
Tundra
Tundra in Summer

Taiga map
Taiga
Taiga
Desert map
Desert
Desert
Dry Desert
Tropical Rain Forest
Tropical Rain Forest

Savana
Savana
Savana