BIO 1070 SOLUTIONS
Variation: differences among individuals within a
population Diversity: number of species in an
area/taxon/clade Disparity: how different species are
from each other
a) Global biodiversity = net outcome of two processes: diversification through speciation + loss through
extinction
b) New species formed by speciation
c) Cladogenesis = ancestral species splitting/branching into two descendant species
d) Allopatric speciation – “different place” (geographic barrier); sympatric speciation – “same place”
(reproductive separation)
e) Species formed by barrier to gene flow
f) Many different definitions for species (complex concept)
Ways to characterize diversity:
within a habitat: alpha diversity OR species evenness
(SDI) across habitats: beta diversity OR gamma
diversity
g) Alpha diversity = number of species within a habitat (species richness)
h) Evenness = Shannon diversity index – how abundant each species is relative to the abundance of other
species in a given habitat
i) Gamma diversity = total number of species across all habitats being studied (analysis moves up in scale)
j) Beta diversity = measure of how different the diversity is between two habitats
k) β = (αH1 – SC) + (αH2 – SC) (SC = number of species common to both habitats)
what determines species composition of a habitat?
- local scale, regional scale, global scale
- species composition = which species live in a particular habitat/relative abundance/spatial pattern
- species distribution = where in the world a particular species lives or doesn’t live/where they are
located relative to each other within a population
I. Endemism – evolved here, found here
, BIO 1070 SOLUTIONS
II. Range expansion – evolved elsewhere, expanded here
III. Range shift – evolved elsewhere, moved here
IV. Long-range dispersal/introduced/invasive – arrived from somewhere else not nearby
V. Vicariance – evolved elsewhere, landscape
changed Dispersal: water-assisted, wind-assisted,
animal-assisted What affects where a species doesn’t
live?
1. Extirpation (in other places but died out elsewhere)
2. It can’t live in those other places
3. Range shift
4. Couldn’t live there even if they arrived there
5. Could live in other places but never dispersed there
6. Could live elsewhere but is excluded by other species that are already there
- Fundamental niche – all possible dimensions in which a species can survive in principle (abiotic + biotic)
- Realized niche – dimensions in which a species actually survives after effects of biotic interactions
1. Competitive exclusion – one species disappears
Variation: differences among individuals within a
population Diversity: number of species in an
area/taxon/clade Disparity: how different species are
from each other
a) Global biodiversity = net outcome of two processes: diversification through speciation + loss through
extinction
b) New species formed by speciation
c) Cladogenesis = ancestral species splitting/branching into two descendant species
d) Allopatric speciation – “different place” (geographic barrier); sympatric speciation – “same place”
(reproductive separation)
e) Species formed by barrier to gene flow
f) Many different definitions for species (complex concept)
Ways to characterize diversity:
within a habitat: alpha diversity OR species evenness
(SDI) across habitats: beta diversity OR gamma
diversity
g) Alpha diversity = number of species within a habitat (species richness)
h) Evenness = Shannon diversity index – how abundant each species is relative to the abundance of other
species in a given habitat
i) Gamma diversity = total number of species across all habitats being studied (analysis moves up in scale)
j) Beta diversity = measure of how different the diversity is between two habitats
k) β = (αH1 – SC) + (αH2 – SC) (SC = number of species common to both habitats)
what determines species composition of a habitat?
- local scale, regional scale, global scale
- species composition = which species live in a particular habitat/relative abundance/spatial pattern
- species distribution = where in the world a particular species lives or doesn’t live/where they are
located relative to each other within a population
I. Endemism – evolved here, found here
, BIO 1070 SOLUTIONS
II. Range expansion – evolved elsewhere, expanded here
III. Range shift – evolved elsewhere, moved here
IV. Long-range dispersal/introduced/invasive – arrived from somewhere else not nearby
V. Vicariance – evolved elsewhere, landscape
changed Dispersal: water-assisted, wind-assisted,
animal-assisted What affects where a species doesn’t
live?
1. Extirpation (in other places but died out elsewhere)
2. It can’t live in those other places
3. Range shift
4. Couldn’t live there even if they arrived there
5. Could live in other places but never dispersed there
6. Could live elsewhere but is excluded by other species that are already there
- Fundamental niche – all possible dimensions in which a species can survive in principle (abiotic + biotic)
- Realized niche – dimensions in which a species actually survives after effects of biotic interactions
1. Competitive exclusion – one species disappears
