Week 13 Flashcards
The Biosphere
The biosphere is the
global sum of all
ecosystems. It can
also be called the zone
of life on Earth.
The biosphere is the
global ecological
system integrating all
living beings and their
relationships, including
their interaction with
the elements of the
lithosphere,
hydrosphere, and
atmosphere
Biogeography:
spatial and temporal
distribution of plants and animals and processes
influencing the
distributions
Ecological Biogeography
Levels of organization
Individual Organism
Population
Community
Ecosystem
Biomes
Organisms and Environment: Plants need
A. Resources:
- all things consumed by an organism
- consumption decreases the supply of resources
Plants need:
1. sunlight in the visible band
2. CO2 from atmosphere
3. H2O from soil
4. nutrients (macro/micro)
5. space to acquire resources
Organisms and Environment: Animals need
A. Resources:
- all things consumed by an organism
- consumption decreases the supply of resources
Animals need:
1. O2 from atmosphere
2. H2O from the environment
3. nutrient and energy sources
(plants and other animals)
4. space to acquire resources
Organisms and Environment: Environmental Factors
- abiotic environmental factors that influence
organisms - not consumed
1. Climatic
2. Geomorphic
3. Edaphic
Climatic Factors -
Temperature
- directly influences physiological processes
- indirectly influences resource needs
Endotherms = “warm-blooded” animals create heat by their metabolism
e.g. mammals
Climatic Factors - Light
Light availability is important in determining plant distribution patterns
Closed Canopy - Shade Open Canopy - Sunlight
Photoperiod - seasonal changes in light
- often triggers biological processes
Edaphic Factors - soil properties
Edaphic factors = soil properties
- soil texture and structure, organic matter, soil
acidity and alkalinity, biological organisms
Geomorphic Factors
Landform attributes: slope steepness, aspect and position
Theory of Tolerance (see q card for visual) RGSTO
Each species is able to exist and reproduce successfully only within a range of values for a particular environmental factor
R = plant grows and Reproduces successfully
G = plant Grows but cannot reproduce
S = plant Survives or persists but cannot grow
T = Tolerance range for that factor, beyond tolerance is lethal
O = Optimum level, at that level maximum
performance
Ecological Niche
Definition: = total structural and functional
role of a species in an ecosystem
Need to consider the resources required,
how it acquires them and the interactions it
has with other parts of the ecosystem
Partly defined by considering the species’
combined tolerance ranges for all the
environmental factors that influence it
an abstract concept, but very important !
Ecological Niche - Biological Factors
Species with overlapping ecological niches interact in one of three ways:
- negative (cost to one or both species)
- positive (benefit to one or both species)
- neutral (no effect)
Negative (cost to one or both species)
Interaction Effect
* competition - , -
* predation + , -
* herbivory + , -
* parasitism + , -
Positive (benefits one or both species)
= Symbiosis
* commensalism + , 0
* mutualism + , +
