Transcript Conclude Conditions and Resources - Powerpoint for Sept. 23.

Ecological Conditions
Atlantic Puffin in Iceland
Acclimatization
• The habituation of an organism's
physiological response to environmental
conditions - usually occurs gradually over a
certain length of time.
Plant Cooling by Transpiration
Antarctic toothfish
Red-Osier Dogwood
Amazonian rain forest distribution today and rain forest
refuges during last glacial period
Margaret B. Davis,
Mother of Paleoecology
Changes in Oak and Spruce distributions
Summary of the effects of conditions on
species distributions
• Lethal conditions may limit distributions
but they only need to occur occasionally in
order to do so.
Saguaro cactus in snow
Summary of the effects of conditions on
species distributions
• Distributions are more often limited by
conditions that are regularly suboptimal
(rather than lethal) leading to a reduction in
growth or reproduction or increased chance
of mortality.
Click beetle on snow
Summary of the effects of conditions on
species distributions
• Suboptimal conditions often act by altering
the outcome of a biological interaction
between the species of interest and other
species.
St. John’sWort – aka Klamath weed
Distribution of St. John’s Wort in
North America
Key: dark blue – present in state; light blue – present in county;
pink – noxious weed
Chrysolina Beetles on St. John’s Wort
Summary of the effects of conditions on
species distributions
• Suboptimal conditions often interact with
other conditions so that it is often
impossible to locate a single condition as
the most important factor.
Mediterranean fruit fly
Summary of the effects of conditions on
species distributions
• Suboptimal conditions are often moderated
by the evolutionary, physiological and
behavioral responses of the organisms.
Kangaroo Rat
Summary of the effects of conditions on
species distributions
• Towards the edge of a species range, it
occupies patches in which conditions are
closest to those found in the center of its
range.
Rufous grasshopper
Rufous grasshopper habitat
• The rufous grasshopper is usually found in open land,
particularly terrain such as meadows, pastures, and forest
edges that feature tall grass. More specifically, it can often
be found in chalk grassland. It has been found on southern
slopes of the Alps up to approximately 8100 feet. It prefers
warm environments of moisture levels ranging from dry to
moist.[3] Very common locations include regions of
Europe, including Germany, Sweden, France, and the
United Kingdom. In fact, it can be found across almost all
of Europe and Asia, ranging from France to parts of
Siberia and from Scandinavia to northern Germany.
• http://en.wikipedia.org/wiki/Rufous_Grasshopper
Relative Humidity
• Relative humidity - is a measure of the
amount of moisture in the air
• all terrestrial organisms must conserve
water and prevent water loss to surrounding
environment - in general the higher the
relative humidity (the amount of water
contained in the air) the less energy an
organism has to expend to conserve water
Transpiration
Joshua Tree – Xerophyte – grow in dry habitats
Water lily – Hydrophyte – grow in wet habitats
Hepatica – Mesophyte – grow in moist habitats
True Xerophyte leaf - Oleander
Hydrophyte – Water Lily leaf cross section
Barrel cactus
Succulent
Desert Ephemerals – South Africa
Desert soil profile – Phreatophytes with deep root systems
Soil pH
• plants suffer direct toxic effects when soil
pH is below 3 or above 9 - there are
naturally occurring soils which have these
pH's
• However at more moderate pH there can be
indirect effects
Salinity
• For aquatic organisms the concentration of
salt in the water presents a condition that
limits distributions
salinity gradient in an estuary
Pollution
Pollution - unfortunately this is becoming a
condition which species must respond to
1. Toxic effects - heavy metals in soils, often
from mine tailings, are deposited onto soil
in high concentrations
2. Acid precipitation
Bent grass –
Agrostis
tenuis
Acid precipitation
• Acid precipitation acts by:
• 1) directly by upsetting osmoregulation - water
balance, enzyme activity or gas exchange,
• 2) indirectly by increasing toxic heavy metal
pollution concentrations by leaching them from
the soil - especially Aluminium,
• 3) indirectly by reducing the quality and range of
food resources available to animals - plants grow
less well
Trees Burnt by Acid Precipitation
– Northeastern U.S.
Resources
• Resources are parts of the physical environment
that are consumed (used up) by living organisms –
There are many different resources –
• For plants – solar radiation, soil nutrients, water,
carbon dioxide, space
• For animals – primarily food sources, oxygen,
space
• For decomposers – a supply of dead organic
matter, oxygen (for some), space
The Niche
• ecological niche - the way in which an
organism interacts with all of the biotic and
abiotic factors in its environment - often
described as how the organism makes its
living, its functional role, but includes the
habitat it occupies
Niches in European seed-eating birds
Common redpoll
Greenfinch
Linnet
Hawfinch
Precursors to theory of the niche:
Liebig’s law of the minimum 1840
Precursors to theory of the niche:
Shelford’s law of tolerance
• The distribution of a species is controlled by
the environmental factor for which the
species has the narrowest tolerance.
G. Evelyn Hutchinson age 18
Hutchinson’s Niche Definitions
• The fundamental niche - the set of resources and
conditions that permits the survival and
reproduction of an organism - many resources and
conditions interact to form the niche.
• The realized niche - the portion of the fundamental
niche actually occupied by the species when
restricted by other organisms - restricted by
competition, predation, parasites, disease.
- Hutchinson 1958
Fundamental vs. Realized Niche
N-dimensional niche
Key point – two species cannot have
identical niche