BIOL 1070: MIDTERM 2
BIODIVERSITY – EVOLUTION AND
ECOLOGY QUIZ
Global Biodiversity:
▪ Global biodiversity is the total outcome of the two opposing processes:
1. Speciation – increase in diversity
2. Extinction – decrease in diversity
▪ These two processes and needed to understand the diversity of life
Forest Biodiversity
Characterizing Diversity:
▪ Within a habitat:
o Alpha (α) species diversity - # of species within a habitat
▪ We know the measurement is accurate if we know the number of
species per specified collection/sample OR if we know the specified
number or individuals
o Species evenness – relative abundance of species in an area
▪ High evenness vs. low evenness
▪ Described using the Shannon Diversity Index (SDI): H’ = - ∑ ni x ln(ni)
, o SDI is a way of calculation how abundant each species is
relative to the abundance of the other species in a habitat –
measures EVENNESS
o Common sense version of equation:
▪ Across habitats:
o Beta (β) species diversity – a measure of how different diversity is
between different habitats
▪ Example:
o
, o
o Gamma (γ) species diversity – total # of species across all habitats
▪ Example:
o
o Within habitat 1: α-diversity = 3 species
o Within habitat 2: α-diversity = 3 species γ-diversity = 5 species
Tree Range Limits and Temperature:
▪ Tree Line:
o The edge of the habitat where trees are capable of growing
, o It is found at high elevations and in cold environments
o Trees cannot tolerate the environmental conditions beyond the tree line
(usually cold temperatures or a lack of moisture)
o Factors that limit the tree line:
▪ Shade (cool) – competition for water
▪ Full sun (hot) – no competition for water
▪ Full sun (hot) competition for water
▪ Treatments:
o Underneath herbaceous canopy (shaded, competition for water)
o On bare soil (a lot of light, no competition)
o On bare soil, surrounded by herbaceous canopy (a lot of light, competition for
water)
Overlapping of Competitors:
1. Competitive exclusion – one of the species disappears from that area
2. Character displacement – both species continue to co-exist, but they diverge to
occupy slightly different ecological niches within the shared habitat
▪ Example:
Niche differentiation
BIODIVERSITY – EVOLUTION AND
ECOLOGY QUIZ
Global Biodiversity:
▪ Global biodiversity is the total outcome of the two opposing processes:
1. Speciation – increase in diversity
2. Extinction – decrease in diversity
▪ These two processes and needed to understand the diversity of life
Forest Biodiversity
Characterizing Diversity:
▪ Within a habitat:
o Alpha (α) species diversity - # of species within a habitat
▪ We know the measurement is accurate if we know the number of
species per specified collection/sample OR if we know the specified
number or individuals
o Species evenness – relative abundance of species in an area
▪ High evenness vs. low evenness
▪ Described using the Shannon Diversity Index (SDI): H’ = - ∑ ni x ln(ni)
, o SDI is a way of calculation how abundant each species is
relative to the abundance of the other species in a habitat –
measures EVENNESS
o Common sense version of equation:
▪ Across habitats:
o Beta (β) species diversity – a measure of how different diversity is
between different habitats
▪ Example:
o
, o
o Gamma (γ) species diversity – total # of species across all habitats
▪ Example:
o
o Within habitat 1: α-diversity = 3 species
o Within habitat 2: α-diversity = 3 species γ-diversity = 5 species
Tree Range Limits and Temperature:
▪ Tree Line:
o The edge of the habitat where trees are capable of growing
, o It is found at high elevations and in cold environments
o Trees cannot tolerate the environmental conditions beyond the tree line
(usually cold temperatures or a lack of moisture)
o Factors that limit the tree line:
▪ Shade (cool) – competition for water
▪ Full sun (hot) – no competition for water
▪ Full sun (hot) competition for water
▪ Treatments:
o Underneath herbaceous canopy (shaded, competition for water)
o On bare soil (a lot of light, no competition)
o On bare soil, surrounded by herbaceous canopy (a lot of light, competition for
water)
Overlapping of Competitors:
1. Competitive exclusion – one of the species disappears from that area
2. Character displacement – both species continue to co-exist, but they diverge to
occupy slightly different ecological niches within the shared habitat
▪ Example:
Niche differentiation
