BISC 100: Lecture 31, 32, 33, 34 :Ecology

ECOLOGY

3 WAYS TO LOOK AT ECOLOGY

ECOLOGICAL LEVELS

BIOSPHERE

Abiotic factors of the biosphere

Biomes

Freshwater biomes

Marine biomes

How climate affects terrestrial biome distribution

Uneven heating of Earth

How climate affects terrestrial biome distribution

How uneven heating of Earth produces various climates

ECOSYSTEM

ECOSYSTEM COMPONENTS

COMMUNITY

DESCRIPTIVE PARAMETERS FOR
COMMUNITIES

BIODIVERSITY:
THREE TYPES

ECOLOGICAL COMMUNITY

STABILITY

TROPHIC STRUCTURE

What is a population?

Population Structure and Dynamics

Density and Dispersion

Density

Dispersion patterns

How to quantify a population?

Mark and Recapture (formula)

Dispersion patterns: CLUMPED

Clumped patterns usually result from

Dispersion patterns: UNIFORM

Dispersion patterns: RANDOM

GROWTH OF A POPULATION
Exponential increase:

The Exponential Growth Model

The Logistic Growth Model

POPULATION GROWTH
CURVES

POPULATION GROWTH IS LIMITED BY
ENVIRONMENTAL RESISTANCE
Density Dependent Factors

POPULATION GROWTH IS LIMITED BY
Density Independent Factors

SURVIVORSHIP CURVES

GROWTH AND REPRODUCTIVE STRATEGIES

Principles of population ecology have practical applications
– Principles of population ecology are useful in managing
natural resources
Three such principles in practice are

3 DETERMINANTS OF
COMMUNITY STRUCTURE

ECOLOGICAL NICHE

RESOURCE UTILIZATION AND TOLERANCE

Opportunistic Populations

Equilibrial populations

APPLICATION OF POPULATION OF ECOLOGY

Human Population Dynamics

Most Populous Cities of the World
2015

What is demographic transition?

What is the age structure of a population?

What is “Ecological Footprint” (EFP)?

The ecological capacity of the world
may already be smaller than

COMMUNITY INTERACTIONS 
1. Competition

COMMUNITY INTERACTIONS
2. PREDATION

Keystone Species

Effects of predation on communities

DEFENSE MECHANISMS AGAINST PREDATORS
PREY’S ADAPTATIONS TO AVOID PREDATION

Adaptation to avoid predation
Camouflage

Adaptation to avoid predation
CHEMICAL DEFENSES: Poison arrow frog

Mimicry

Adaptation to avoid predation
Deceptive mimicry: Mullarian mimicry

Coevolution of Predator and Prey

1. COMMENSALISM

2. MUTUALISM

3. PARASITISM

3B. INTERNAL PARASITISM: ENDOPARASITE
7
Extremely Specialized:

3C: Brood Parasitism

SUMMARY OF COMMUNITY
INTERACTIONS

In short: Ecological succession

Disturbance is a prominent feature
of most communities
– Disturbances are events thaT

Primary succession

Secondary succession

– Energy flow and chemical cycling

Trophic relationships

Trophic levels

Energy flow

–Chemical cycling

Trophic structure is a key factor in
community dynamics

Herbivores, which eat plants, algae, or autotrophic
bacteria, are the

Secondary consumers

Tertiary consumers

Quaternary consumers

Detritivores, or decomposers

Food chains
interconnect,
forming food webs

Productivity and the Energy Budgets of Ecosystems

An energy pyramid

Ecosystem alteration can upset chemical
cycling

Environmental changes caused
by humans, such as