Transcript Introduction to Ecology

Introduction to Ecology
Chapter 19
19.1

Ecology
The study of the interactions between
organisms and the living & nonliving parts of
the environment
Humans have always needed to understand
ecology in order to survive
Today’s Environment
Early human cultures were Hunter-Gatherers (relied on
practical knowledge about the environment)
Current human cultures need to
understand the critical impact they
have on the Earth (depletion of
natural resources)
Human Population

The human population has steadily increased

There was a rapid increase after the industrial
revolution (better hygiene, transportation,
vaccinations, food harvest and shipment)

According to the U.N., the world population
could be between 7.8 – 12.5 billion by 2050
Effects of the Human Population

As the human population continues to grow,
we increase the demand for Earth’s resources

Since all life is interconnected, human
destruction of habitats and contamination from
our pollution will have an impact on all living
organisms
The Sixth Mass Extinction

According to fossil records, there have been 5
mass extinctions in the past

Currently, we are experiencing the 6th mass
extinction!

The overpopulation of humans is causing
species to become extinct on a daily basis
Ozone Depletion

Ozone layer protects
living organisms from
harmful UV radiation

Chlorofluorocarbons
(CFC’s) chemically
react with the ozone and
destroy it
Ozone Depletion



Although the depletion occurs over most of the
planet, it is most concentrated over Antarctica
The ozone hole led to the ban of CFC’s in
1992
Currently, 1% of UV rays reaches
Earths surface and causes ½ million
cases of skin cancer each year
Climatic Changes

Greenhouse Effect: carbon
dioxide and water vapor in
the atmosphere redirect
Earth’s reflected heat and
keep the planet warm
enough to sustain life

Human activities are
continually increasing the
amount of CO2 in the
atmosphere
Global Warming

As fossil fuels are burned, CO2 is released

More people + more fossil fuels being used = a
warmer planet

More CO2 in the atmosphere results in more
heat being redirected back at our planet
Impacts of Global Warming

The average global temperature will increase 3-8º F
by 2100

Polar ice caps are already melting faster than
expected

Changes in rainfall and weather
patterns will lead to famine,
starvation, and disease
Levels of Organization in Ecology
The Biosphere

Where all life is found on
Earth

Extends 8-10 km above
Earth’s surface and below
the ocean into the deepest
parts

Most organisms are found
within a few meters of the
surface of the land or oceans
Ecosystems

Includes all of the organisms (biotic factors)
and the nonliving components (abiotic factors)
in a particular place

Example: a pond ecosystem
Community

All of the interacting
organisms living in an
area

Ecologists study how
species interact and how
these interactions
influence the entire
community
Population

All the members of a species that live in the
same place at the same time
Organism

Refers to a living thing

Ecologists study the adaptations that an
organism has that helps it overcome the
challenges in its environment
Key Theme

All life is interconnected!
No organism is isolated!

Survival of a species
(including humans) depends
on interdependence

Example: humans could not
survive without the
nitrogen-fixing bacteria that
live in the roots of legume
plants
Disturbances in Ecosystems

One change in an ecosystem will affect many
species

Example: logging a forest (results in less
habitat for all animal species, increases runoff
that leads to water pollution, less trees using
the atmospheric CO2 , etc.)
Ecological Models

Models are often used when studying
ecosystems

Can be graphs, diagrams, or mathematical
equations
19.2 Ecology of Organisms

Where an organism lives depends on its
evolutionary history, its tolerances and
requirements, the history and conditions of its
habitat, and many other factors
Biotic and Abiotic Factors

Biotic factors- includes the living and once
living components

Abiotic factors- nonliving components such as
the physical and chemical characteristics of the
environment
The Changing Environment

Abiotic factors are always changing (daily
temperature changes, rainfall, seasons, etc)

Organisms are adapted to function within a
specific range of temperatures

An organism cannot survive in areas
where the temperatures are beyond its
tolerance
Acclimation
An organism’s adjustment to an abiotic factor
Occurs within the lifetime of an individual
(NOT an adaptation!)
Example: goldfish raised at higher temps. will
have a different tolerance curve
Control of Internal Conditions


Conformers: organisms that don’t regulate
their internal conditions (example: desert
lizards)
Regulators: organisms that use energy to
control some of their internal conditions
(example: mammals)
Escape from Unsuitable Conditions


Dormancy: a state of reduced activity during
periods of unfavorable environmental
conditions
Examples: hibernation and estivation
Migration


Moving to a more favorable habitat to escape
unfavorable conditions
Example: bird migration
Resources

Refers to the energy and materials a species
needs to survive

Includes food, nesting sites, territory, water,
sunlight, optimal temperature range
The Niche

A species way of life or its role in the
environment

Includes the range of conditions the species
can tolerate, how it obtains its resources, the
number of offspring, time of reproduction, etc.
Fundamental vs. Realized Niche

Fundamental niche- the entire range of
conditions and resources that a species could
potentially utilize (very broad)

Realized niche- includes what is actually used
by a species
Niche Differences

Generalists: species with
broad niches (can tolerate a
range of conditions and use
a variety of resources)
example: moths

Specialists: species with
narrow niches (feed on a
limited type of resources)
example: butterflies