Download Why is ecology important?

20-Aug-13
Chapter 1
Overview
Why Studying Ecology and Environmental Science; Levels of Studying Ecology; Differences among Ecological
and Environmental Studies
Why is ecology important?










----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------2
1
20-Aug-13
It is important to clarify the difference
between Ecology and Environmental Science

Ecology, is the scientific study of the distribution and
abundance of organisms, while environmentalism,
advocacy for the protection or preservation of the
natural environment.

To address environmental problems, we need to
understand the interactions of organisms and the
environment where.


The science of ecology provides that understanding.
Ecology provides a scientific context for evaluating
environmental issues
3
Environmental science



It can help us avoid mistakes made by past civilizations.
Can we act more wisely to conserve our resources?
The lesson of Easter Island: people annihilated their
culture by destroying their environment.



Easter Island, also called Rapa Nui, was annexed by Chile in 1888.
Easter Island is small, but its story is a dark one that suggests
what can happen when people use up the resources of an
isolated area.
New data suggest that people first arrived about 800 years ago,
certainly played a role in the loss of trees (Deforestation), and the
rats that arrived with the Polynesians were evidently responsible
for eating seeds of the palm trees, preventing regeneration.
4
2
20-Aug-13
Overview of Ecology

Ernst Haeckel, The Founders
of the term “ECOLOGY” was
the German zoologist, in 1866

Haeckel – 1870 – “By ecology we
mean the body of knowledge
concerning the economy of nature
– the investigation of the total
relations of the animal both to its
inorganic and organic
environment”
Ernst Haeckel
5
Definitions of Ecology

Tansley – 1904 – (Ecology is) Those relations of plants, with
their surroundings and with one another, which depend
directly upon differences of habitat among plants.

Elton – 1927 – Ecology is the new name for a very old
subject. It simply means scientific natural history.

Andrewartha – 1961 – Ecology is the scientific study of the
distribution and abundance of organisms.
6
3
20-Aug-13
Definitions of Ecology

Krebs – 1972, 2008 – Ecology is the scientific study of the
interactions that determine the distribution and abundance of
organisms.

Townsend et al. 2003 – Ecology is the scientific study of the
distribution and abundance of organisms and the interactions
that determine distribution and abundance.
7
Ecology

Ecology (from the Greek oikos, home, and logos, study)

Ecology is the scientific study of the interactions between
organisms and the environment
 Interactions determine both the distribution of
organisms and their abundance
 Ecological interactions occur at a hierarchy of scales
that ecologists study, from single organisms to the
globe
8
4
20-Aug-13
Ecology is an interdisciplinary science
9
Levels (subfields) of Ecology:
1.
2.
3.
4.
5.
6.
Organismal ecology: Studies how an organism’s structure,
physiology, and (for animals) behavior meet the challenges
posed by the environment.
Population ecology: Concentrates mainly on factors that
affect how many individuals of a particular species live in an
area
Community ecology: Deals with the whole array of
interacting species in a community
Ecosystem ecology: Emphasizes energy flow and chemical
cycling among the various biotic and abiotic components
Landscape ecology: Deals with arrays of ecosystems and
how they are arranged in a geographic region
Global Ecology (The biosphere): is the global ecosystem,
the sum of all the planet’s ecosystems.
10
5
20-Aug-13
Galaxies
Solar
system
Scale
Earth
ECOLOGY
Ecosystems
Communities
Community ecology
Populations
PHYSIOLOGY
Organisms
Organs
Different
levels of
studying
ecology
Tissues
Cells
CELL BIOLOGY
BIOCHEMISTRY
Molecules
Atoms
Ecology 2005
The organizational levels of ecology
Biogeography



Biogeography is studying the Factors affecting the distribution
of organisms
Biogeography is the study of the geographic distribution of
organisms throughout the landscape
Biogeography provides a good starting point for understanding
what limits the geographic distribution of species
12
6
20-Aug-13
Species Dispersal

Dispersal refers to the process of distribution of
individuals within geographic population boundaries

Ecological (Adaptive) Dispersal: "why it happens"

Movement to new, unused resources (away from parents)



Within same habitat
Across barrier to new habitat (within range)
Successful Dispersal depends on "long distance" transport


withstanding unfavorable conditions during travel and upon
early arrival
establishing a viable population
13
Kinds of Dispersal
Three Kinds of Dispersal Leading to Range Expansion
 Jump Dispersal long distances over inhospitable habitat



Diffusion movement into adjacent habitats as population
expands




example: oceanic islands
mostly by volant organisms (flight) ex.: Galapagos Islands
Plants: purple loosestrife, halogeton, storksbill
Birds: cattle egret, starlings, house sparrows
muskrat, armadillo, nutria (Myocastor coypus)
Secular Migration: geological times scale


Plants: diversification and spread of flowering plants
Animals: spread of camels from North America to S. America and Asia
14
7
20-Aug-13
Dispersal Mechanisms

Active Dispersal


strong fliers
annual migrators


examples: golden plover (is a shore bird that breeds during the Arctic
summer, and then flies to the southern hemisphere during its summer.
Passive Dispersal Mechanisms:

Plants
15
Behavior

Why Organisms may not occupy all potentially suitable
habitat ?



Evolution doesn’t lead to perfect organisms.
Evolution is an ongoing process.
Environments change, but it takes a while for organisms to
respond.
16
8
20-Aug-13
Biotic factors

Did organisms required for potential community
members to colonize may be lacking?

Pollinators, prey, predators that limit competition
17
Abiotic factors

Are there any Abiotic factors affect distribution?





Temperature (range from 0 to 45 C)
Water
Sunlight
Wind (increases heat & water loss)
Rocks and soil
18
9
20-Aug-13
Influence of Precipitation and Temperature on
Vegetation
19
Relationship Between
Height above Sea
Level, Latitude, and
Vegetation
Mountains built by
geological processes
and thus concentrated
in belts of geological
activity.
Climate changes with
elevation and
latitude.
Soils are generally welldrained and thin.
Flora and fauna change with
elevation.
Historically used as a
source of raw materials
for human settlements.
10
20-Aug-13
Mountains
21
Aquatic and Terrestrial Biomes
Biome is
major
ecosystem
type
22
11
20-Aug-13
Aquatic biomes

Cover about 75% of the earth’s surface
- Wetlands
- Lakes
- Rivers, streams
- Intertidal zones
- Oceanic pelagic biome
- Coral reefs
- Benthos
23
12
20-Aug-13
Oligotrophic Lake: Nutrient poor, water is clear,
oxygen rich; little productivity by algae, relatively
deep with little surface area.
Eutrophic lake:
nutrient rich, lots of
algal productivity so
it’s oxygen poor at
times, water is
murkier  often a
result of input of
agricultural fertilizers
13
20-Aug-13
Rivers and Streams: Organisms need adaptations
so that they are not swept away by moving water;
heavily affected by man changing the course of
flow (E.g. dams and channel-straightening) and by
using rivers to dispose of waste.
Wetlands:
includes marshes, bogs, swamps, seasonal ponds. Among
richest biomes with respect to biodiversity and productivity.
Very few now exist as they are thought of often as
wastelands.
14
20-Aug-13
Estuary:
Place where freshwater stream or river merges with the
ocean. Highly productive biome; important for fisheries and
feeding places for water fowl. Often heavily polluted from
river input so many fisheries are now lost.
Marine environment
with zonation
15
20-Aug-13
Intertidal Zone:
Alternately submerged and
exposed by daily cycle of
tides. Often polluted by oil
that decreases biodiversity.
Coral Reefs:
occur in neritic zones of
warm, tropical water,
dominated by cnidarians
(corals); very productive,
protect land from storms;
most are now dying from
rise in global temperatures
16
20-Aug-13
Deep-sea vent:
Occurs in benthic
zone; diverse,
unusual organisms;
energy comes not
from light but from
chemicals released
from the magma.
Terrestrial Biomes

Biomes are distinguished primarily by their predominant plants
and are associated with particular climates.

Geographic and seasonal variations in temperature and precipitation
are fundamental components.
- Tropical forest
- Savanna
- Desert
- Chaparral
- Temperate grassland
- Temperate deciduous forest
- Coniferous forest
- Tundra
34
34
17
20-Aug-13
Tropical Forest:
Vertical stratification with trees in canopy blocking light
to bottom strata. Many trees covered by epiphytes
(plants that grow on other plants).
18
20-Aug-13
Tropical Rainforests
Annual rainfall of 2,000 4,000 mm relatively
evenly distributed.
38
19
20-Aug-13
Tropical, Dry Forest
Tropical Dry Forest
40
20
20-Aug-13
Savanna
Tropical Savanna
42
21
20-Aug-13
Desert: Sparse rainfall (< 30 cm per year), plants and
animals adapted for water storage and conservation. Can
be either very, very hot, or very cold (e.g. Antarctica)
Desert
44
22
20-Aug-13
Chaparral:
Dense, spiny, evergreen shrubs, mild rainy winters; long,
hot, dry summers. Periodic fires, some plants require fire
for seeds to germinate.
Mediterranean Woodland and Shrubland
46
23
20-Aug-13
Temperate Grassland:
Marked by seasonal drought and fires, and grazing by large
animals. Rich habitat for agriculture, very little prairie
exists in US today.
Temperate Grassland
Annual rainfall 300 1,000 mm.
48
24
20-Aug-13
Temperate Deciduous Forest:
Mid-latitudes with moderate amounts of moisture, distinct
vertical strata: trees, understory shrubs, herbaceous substratum. Loss of leaves in cold, many animals hibernate or
migrate then. Original forests lost from North America by
logging and clearing.
Temperate Forest (Old Growth)
Rainfall averages 650
- 3,000 mm.
50
25
20-Aug-13
Coniferous forest: Largest terrestrial biome on earth, old
growth forests rapidly disappearing, usually receives lots
of moisture as rain or snow.
Boreal Forest (Taiga)
52
26
20-Aug-13
Tundra:
Permafrost (Permanent frozen ground), bitter cold, high
winds and thus no trees. Has 20% of land surface on
earth.
Tundra
200 - 600 mm
precipitation
54
27
20-Aug-13
What is Environmental Science?

Environment (from the French environner: to encircle
or surround) can be defined as
(1) the circumstances or conditions that surround an
organism or group of organisms, or
(2) the complex of social or cultural conditions that
affect an individual or community
55
Human Environment: the total of our
surroundings

All the things around us with
which we interact:
•
Abiotic components: nonliving
chemical and physical factors such
as temperature, light, water, and
nutrients.
Biotic components: all living
organisms in the individual’s
environment.
Our built environment: Buildings,
human-created living centers
Social relationships and institutions
•
•
•
56
28
20-Aug-13
Humans and the world around us

Humans change the environment, often in ways not fully
understood

We depend completely on the environment for survival

Increased wealth, health, mobility, leisure time
But, natural systems have been degraded

Environmental changes threaten long-term health and survival



i.e., pollution, erosion and species extinction
Environmental science is the study of:


How the natural world works
How the environment affects humans and vice versa
57
Global Human
Population Growth


More than 6.7 billion
humans
Why so many humans?

Agricultural revolution


Stable food supplies
Industrial revolution



Urbanized society
powered by fossil fuels
Sanitation and medicines
More food
58
29
20-Aug-13
Natural resources: vital to human survival

Natural resources = substances and energy sources
needed for survival
59
Why studying Environmental Science

Environmental Science: The scientific study of the
influence of human actions on natural processes




Environmental science helps us understand our relationship
with the environment and informs our attempts to solve and
prevent problems.
Identifying a problem is the first step in solving it
Solving environmental problems can move us towards health,
longevity, peace and prosperity
Environmental science can help us find balanced solutions to
environmental problems
60
30
20-Aug-13
Environmental Impact

Environmental impact refers to the alteration of the natural
environment by human activity
 Resource depletion and pollution were the two basic
types of environmental impact

Environmental Ecology: The study on the impacts of pollution and
other stresses on ecosystem structure and function.
61
Environmental science is not
environmentalism

Environmental science



The pursuit of knowledge about the
natural world
Scientists try to remain objective
Environmentalism

A social movement dedicated to
protecting the natural world
62
31