1. There are various patterns of distribution for different species based on factors like habitat, geography, and climate. No two species have an identical distribution. 2. The causes of distribution patterns vary depending on the taxonomic level from broad families to specific genera. 3. Distribution patterns also vary depending on the spatial scale examined from global to local levels. Key factors that influence patterns include geological history, climate, food and habitat availability, competition, and human activities.

1. Concepts on Patterns of
Distribution and Biodiversity
Baldeo, Cortez, Delos Santos, Olivar,

2. Concepts on Patterns of
Distribution

3. 1. No two species are identical in their patterns of
distribution
Both species occupy the same
tree. (A) Apteryx australis
occupies the floor (B)
Rhipidura fuliginosa occupies
the canopy branches
(A)
(B)
MICROHABITAT
concept

4. Global patterns of terrestrial vertebrate diversity analyzed in the study. Each of the 32 bioregions is colored
by its vertebrate species richness (amphibian, reptile, bird, mammal richness combined; dark green
represents the lowest values and dark red represents the highest values) (Jetz & Fine, 2012)

5. 2. Causes of pattern vary according to the taxonomic
level
Distribution of the
Asteraceae Family
Distribution of the
Helianthus genus

6. 3. Causes of patterns also vary with the spatial scale

7. 4. Factors in patterns of distribution
Geological history
Climate
Availability of food Chemistry of Environment
Competition

8. 5. Species introduction led to new patterns of
distribution
Macropus eugenii was thought to be extinct in Australia
for 100 years. But it has been rediscovered in an island in
New Zealand (2000 species) where a former governor of
that country introduced the species in 1862.
Introduction of mahogany species in the Philippines led to
hectares of biodiversity-dead zones.

9. 6. Spatial and temporal isolation leads to speciation

10. 7. Migration constitutes a special kind of dynamic
pattern
Ancient human migration patterns as derived from mitochondrial DNA analysis

11. Concepts on Patterns of
Biodiversity

12. 8. Biodiversity means the full range of life on earth
Genetic Diversity
Ecosystem Diversity
Species
Diversity

13. 9. Knowledge on global diversity must be established to
appreciate the increasing extinction rate of species
• Since there is no absolute idea on how many species existed
in the first place, extinction rates are vaguely estimated
• Little is known about extinction rates of microorganisms
• We can rarely be sure that a species is actually lost, that no
isolated members remain

14. 10. Out of the 30 million species on Earth, only 1.8
million species have been described
(Groombridge, 1992)

15. 11. The tropics have the highest species diversity
Latitudinal gradients of species richness for swallow tail butterflies in three parts of the world. (Collin & Morris, 1985)
High species diversity is due to:
a. high productivity and food availability
b. high biomass and hence complex structure
c. past patterns of evolution
d. survival of fragments of habitats through the cold episodes of the last 2
million years
e. degree of small-scale disturbance  mosaic of successional processes

16. 12. Diversity involves species richness and evenness
and generally increases during the course of succession
Increasing diversity

17. 13. Biodiversity in a community is dynamic but there
are also stabilizing forces at work
• Neutral Theory of Biodiversity (Hubbell, 2001)
– Chance plays a great a great part in determining what
species are present in the ecosystem
• Chaos Theory
– Very small chance events can determine the ultimate
outcome of the ecosystem

18. 14. There is a tendency for human populations to be
dense in biodiversity hotspots.
The Crete Island in Greece
a. supported human populations ever since the Neolithic age
b. only 245 km long by 50 km wide and isolated for 5.5 million years
c. human population reaching 1 million yet supports a highly diverse
community (10% of the species are endemic to the island)
Anthropogenic activities lead to HABITAT DIVERSIFICATION which promotes an increase
in biodiversity. There is evidence that biological diversity and human population density
are positively related over the less extreme density range. (Cox & Moore, 2005)