PHILIPPINE BIOGEOGRAPHY

Question 1

What are the three tectonic plates

Answer 1

Philippine Sea Plate
Eurasian Plate
Sunda Plate

These groups encompass over 7,600 islands.

Question 2

What plate?

(particularly the microcontinental block of Palawan); shares geological affinity with southern China and the rest of Sundaland.

Answer 2

Sunda Plate

This indicates a high level of biodiversity unique to the Philippines.

Question 3

What role does the Philippine Sea Plate play in the geological formation of the Philippines?

Answer 3

Shapes eastern Luzon, Samar, and Mindanao

It is one of the tectonic plates contributing to the archipelago’s formation.

Question 4

Eurasian plate contributes to the formation of the (2)

Answer 4

Central Cordillera and Sierra Madre mountain ranges

This trench is where the Eurasian Plate dives beneath Luzon.

Question 5

• were formed by the subduction zones.
• not only cause earthquakes and volcanoes, but also drive the emergence of new islands and influence species evolution, shaping the Philippines into a biogeographic hotspot.

Answer 5

Trenches

Question 6

What are the two trenches

Answer 6

Philippine Trench
Manila Trench

Question 7

What is the Philippine Trench?

Answer 7

A subduction zone where the Philippine Sea Plate is subducting westward

It is located east of the Philippine islands.

Question 8

trench at west, represents the Eurasian Plate diving beneath Luzon

Answer 8

Manila Trench

Question 9

Some of these blocks, like ________ and ________, were once part of the Sundaland continent

Answer 9

Palawan and Mindoro

Question 10

Timeline:

~45–30 Ma (Eocene to Mid Oligocene)

~30 Ma (Mid Oligocene)

~20 Ma (Early Miocene)

~15–10 Ma (Middle to Late Miocene)

~10–15 Ma

~5 Ma (Early Pliocene)

Answer 10

~45–30 Ma (Eocene to Mid Oligocene): Palawan forms as part of the Sunda Shelf (North Palawan Block).

~30 Ma (Mid Oligocene):
Proto-Luzon and Visayan terranes begin forming through tectonic collisions and subduction.
Mostly submerged under shallow seas — not yet suitable for terrestrial life.
Mindoro forms as a transitional continental fragment (North Palawan Block), possibly emerging shortly after Palawan.

~20 Ma (Early Miocene):
Eastern Luzon, including the Sierra Madre range, starts to rise above sea level.
First opportunities for biological colonization by flying organisms (e.g., birds, insects).
Formation of habitable volcanic islands begins in the Philippine Mobile Belt.

~15–10 Ma (Middle to Late Miocene):
Visayan islands begin to emerge above sea level.
Increasingly fragmented island landscapes develop.
Opportunities for dispersal, isolation, and early speciation grow.

~10–15 Ma:
Visayan islands begin emerging above sea level.
Increasingly complex island landscapes form.

~5 Ma (Early Pliocene):
Eastern Mindanao terranes rise above sea level.
Final major pieces of the modern Philippine archipelago fall into place.
Full establishment of isolated evolutionary “island arenas”.

Question 11

What is the significance of PAICs in biogeography?

Answer 11

• Explain species distribution and evolutionary isolation.
• Support high levels of endemism in the Philippines.
• Useful framework for conservation planning and protected area design.
• Help trace evolutionary history and faunal migration patterns.

PAICs support high levels of endemism and are useful in conservation planning.

Question 12

What does PAIC stand for?

Answer 12

Pleistocene Aggregate Island Complex

PAICs were groups of islands connected during the Pleistocene epoch.

Question 13

List the major PAICs in the Philippines.

Answer 13

• Greater Luzon PAIC
• Greater Mindanao PAIC
• Greater Palawan PAIC
• Greater Negros–Panay PAIC
• Greater Sulu PAIC

These PAICs reflect historical land connections during glacial periods.

Question 14

Greater Luzon PAIC

Answer 14

Luzon, Polillo Islands, Marinduque, Catanduanes

Includes unique species like the Luzon Tree Mouse and Luzon Bleeding-heart Dove.

Question 15

Greater Mindanao PAIC

Answer 15

Mindanao, Leyte, Samar, Bohol, Camiguin

It supports unique species like the Tamaraw and Mindoro Short-legged Skink.

Question 16

Greater Palawan PAIC

Answer 16

Palawan, Balabac, Busuanga, Culion

Question 17

Greater Negros–Panay PAIC

Answer 17

Negros, Panay, Guimaras, Masbate, Cebu, Ticao

Question 18

Greater Sulu PAIC

Answer 18

Basilan, Jolo, Tawi-Tawi, Pangutaran

Question 19

MINOR PAICS

Answer 19

• Mindoro PAIC: Mindoro Island (not connected to Luzon or Palawan during the Pleistocene)
• Romblon PAIC: Romblon Islands (Sibuyan, Tablas, Romblon)
• Babuyan PAIC: Babuyan Islands north of Luzon (e.g., Calayan, Camiguin Norte)
• Batanes PAIC (sometimes treated separately): Batan Island, Itbayat, Sabtang (distinct biogeographic origin)
• Sibutu–Simunul PAIC (borderline PAIC near Borneo): Sibutu and Simunul (now politically part of Tawi-Tawi but historically distinct)

Question 20

Formation: These islands were connected during glacial sea-level lows. Luzon formed from volcanic island arcs and accreted terrains during the Cenozoic.

Geological Background: Proto-Luzon originated from volcanic activity; it merged with other blocks over time.

Answer 20

Greater Luzon PAIC

Question 21

Formation: These Visayan islands were once connected to Mindanao due to lower sea levels.

Geological Background: Formed through subduction-related volcanism and the tectonic compression of the Philippine Mobile Belt.

Answer 21

Greater Mindanao PAIC

Question 22

Formation: Was never submerged entirely and became connected to Borneo during glacial maxima.

Geological Background: Continental origin (not volcanic); Palawan rifted from the Asian mainland in the Oligocene

Answer 22

Greater Palawan PAIC

Question 23

Formation: Connected during glacial periods; land bridges joined these islands due to lowered sea levels.

Geological Background: Mostly volcanic, part of the Visayan arc, uplifted through subduction dynamics.

Answer 23

Greater Negros–Panay PAIC

Question 24

Formation: These islands formed a single landmass during the Pleistocene glacial maxima.

Geological Background: Volcanic island arc related to the Sulu Trench subduction system.

Answer 24

Greater Sulu PAIC

Question 26

What is the significance of topographic variation in the Philippines?

Answer 26

Influences faunal distribution and creates diverse habitats ## Footnote Elevation gradients affect temperature, humidity, and vegetation types.

Question 27

Which species is endemic to the Greater Mindanao Faunal Region?

Answer 27

Philippine Eagle (Pithecophaga jefferyi) ## Footnote This species is the largest eagle and is forest-dependent.

Question 28

What type of forests characterize the Greater Palawan Faunal Region?

Answer 28

Karst limestone forests, lowland and montane forests, mangroves ## Footnote This region shares many species with Sundaland, unlike the rest of the Philippines.

Question 29

What is the main reason for high endemism in the Sulu Faunal Region?

Answer 29

High isolation and small island size ## Footnote This leads to micro-endemism among species.

Question 30

Fill in the blank: The Philippines is a global biodiversity hotspot with over _____ plant species.

Answer 30

14,000 ## Footnote More than 3,500 of these species are endemic.

Question 31

What geological process contributed to the formation of Mindoro?

Answer 31

Tectonic collisions and subduction ## Footnote Mindoro is a transitional continental fragment.

Question 32

What is the primary habitat type found in the Greater Negros–Panay PAIC?

Answer 32

Volcanic islands ## Footnote These islands were connected during glacial periods.

Question 33

What type of climate variation exists in the Philippines?

Answer 33

Varies significantly due to elevation, monsoonal influence, and geographic position ## Footnote This affects the types of habitats and species present.

Question 34

What is the total number of plant species in the Philippines?

Answer 34

Over 14,000 species ## Footnote More than 3,500 of these are endemic species.

Question 35

What are the major threats to Lowland Dipterocarp Forests?

Answer 35

Commercial logging, conversion to farmland, road expansion ## Footnote These activities fragment habitats and threaten biodiversity.

Question 36

What characterizes Montane and Mossy Forests?

Answer 36

High altitude, cooler temperatures, high humidity, rich in mosses and orchids ## Footnote These forests are typically found at elevations from 800 to over 2,500 meters.

Question 37

Which species are key flora in Mangrove Forests?

Answer 37

* Rhizophora stylosa * Avicennia officinalis * Xylocarpus granatum ## Footnote Mangroves are crucial for protecting shorelines and supporting marine biodiversity.

Question 38

What functions do Beach and Strand Forests serve?

Answer 38

* Dune stabilization * Provide nesting areas for sea turtles ## Footnote These forests are often cleared for development, impacting their ecological roles.

Question 39

What is unique about Ultramafic and Limestone Forests?

Answer 39

Grow on challenging substrates, rich in heavy metals and high alkalinity ## Footnote Plants here have evolved unique adaptations to survive.

Question 40

What is the significance of endemism in Philippine flora?

Answer 40

High level of plant endemism with many species found nowhere else ## Footnote This contributes to the Philippines being a global biodiversity hotspot.

Question 41

What are Rafflesia species known for?

Answer 41

World's largest flowers, holoparasites dependent on host vines ## Footnote They emit a rotting meat odor to attract pollinators.

Question 42

What adaptations do Nepenthes plants showcase?

Answer 42

Modified leaves forming pitchers to trap prey ## Footnote They digest insects and sometimes small vertebrates.

Question 43

Which island is known for the critically endangered Philippine eagle?

Answer 43

Mindanao ## Footnote This island is a stronghold of Philippine biodiversity.

Question 44

What is the ecological role of bat pollination in the Philippines?

Answer 44

Increases fruit yield and is vital for plant reproduction ## Footnote An example is the bat pollination of durian trees.

Question 45

What is a significant factor influencing species distribution in the Philippines?

Answer 45

Biogeographic compartmentalization of over 7,600 islands ## Footnote This leads to localized endemism and unique ecological zones.

Question 46

What is the relationship between flora and fauna in ecological systems?

Answer 46

Interdependence influences species distribution and ecosystem structure ## Footnote Co-evolutionary dynamics shape these relationships.

Question 47

What does the term 'chiropterophilous pollination' refer to?

Answer 47

Pollination by bats ## Footnote It is exemplified by the durian tree and its bat pollinators.

Question 48

What is the significance of Wallace's Line?

Answer 48

Biogeographic boundary separating Asian-dominated fauna from Wallacea ## Footnote It highlights the distinct evolutionary paths of species in these regions.

Question 49

Fill in the blank: The Philippine eagle is critically endangered due to _______.

Answer 49

Habitat loss and hunting

Question 50

True or False: The Philippines shares many large mammal species with Sundaland.

Answer 50

False ## Footnote The Philippines lacks many large mammals found in Sundaland due to geographic isolation.

Question 51

What does the term 'faunal niches' refer to?

Answer 51

Unique ecological roles filled by species in diverse habitats ## Footnote Examples include specific animals adapted to lowland dipterocarp forests.

Question 52

What are two unique mammals found in Australia?

Answer 52

Echidnas, platypus

Question 53

What is the primary origin of the fauna in Australia?

Answer 53

Asian origin

Question 54

What are Wallace's Line and Weber's Line?

Answer 54

Biogeographic boundaries separating Asian-dominated fauna from Wallacea

Question 55

What is the Coral Triangle?

Answer 55

A globally recognized center of marine biodiversity

Question 56

Which countries are encompassed by the Coral Triangle?

Answer 56

Indonesia, Malaysia, the Philippines, Papua New Guinea, Timor-Leste, Solomon Islands

Question 57

What types of marine organisms have the highest diversity in the Coral Triangle?

Answer 57

Coral species, reef fishes, mollusks, crustaceans

Question 58

True or False: The Philippines has a distinct terrestrial biota with no shared marine biodiversity.

Answer 58

False

Question 59

Fill in the blank: The interconnectedness of marine environments within the Coral Triangle allows for the dispersal of _______ and propagules via ocean currents.

Answer 59

larvae

Question 60

What is the significance of the marine environment of the Philippines in relation to its Southeast Asian neighbors?

Answer 60

It shares a crucial biogeographic link

Question 61

What allows for a high degree of shared biodiversity among the nations in the Coral Triangle?

Answer 61

Ocean currents