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 + , +
Ecological Biogeography: Levels of Organization
Individual Organism
Population
Community
Ecosystem
Biomes
Definitions: population and community
Population: a group of individual organisms
of the same species occupying a given area at the same time.
Community: groups of interacting populations of different species in the
same place at the same time
Ecosystem
Ecosystem: self-sustaining association of living plants, animals and non-physical environment
- Biomes: dominant vegetation formation associated with specific
climatic conditions
Biodiversity
The variability among living organisms from all sources and the ecological complexes of they are a part.
This includes diversity within species, between species, within communities, ecosystems and landscapes.
How many species exist today?
~1.75 million species known to western science
estimates of 4-30 million species
New species identified each year…
* terrestrial invertebrates
* soil and subterranean organisms
* freshwater fish and other organisms
* marine organisms
Measuring Biodiversity
Species diversity
-a combination of species richness and evenness
Species richness
- the number of species per unit area
(e.g., a count)
Species evenness
- distribution of individuals among species
(e.g., a measure of equitability)
Biodiversity: Beyond Richness
Richness = number
of species per unit
area
Evenness =
equitability or
distribution of
individuals
Diversity Indices =
combine richness and
evenness
Extinction
- the fate of all
species - unique genome is
lost forever - ancestor becomes
extinct as new
species evolves
