1. Adaptive Radiations and Evolutionary Change on the Hawaiian Islands
Presentation By Diana Roberts
June 3, 2003

2. Questions, Questions
What are adaptive radiations and what criteria defines them?
What role does evolution play in adaptive radiations and the rate at which they occur?
What are some examples of adaptive radiations in Hawaiian birds, insects and plants?
Why is adaptive radiation important to the speciation of animals?

3. Adaptive Radiations
Adaptive Radiation is the evolution of a single ancesteral species into several new species within a relatively short amount of time in a specific geographic area
Adaptive Radiations describe the process by which a group adapts to a broad variety of situations, such as changed ecological environment, dispersal barrier and lack of competition or preditors

4. Evolution
Evolution is the process of change in the traits of organisms or their populations over time
Evolutionary changes occur in populations as a result of genetic mutations that are passed to surviving generations or eliminated
Natural selection can result in the formation of new species by promoting the species with the better advantage in the specific environment

5. Speciation
Allopatric Speciation: Speciation that occurs when two populations that are geographically isolated from each other enough to diverge into different species
Parapatric Speciation: Speciation that occurs when two populations that live in adjacent, bordering territories with no barrier between them diverge far enough to form different species
Sympatric Speciation: Speciation that occurs when members of a single population, all living in the same environment diverge to form distinct species

6. Criteria for Adaptive Radiation
Reproductive Isolation
Ecological Isolation
Exploitation of ecological niches- high islands good place because populations can be seperated by physical features such as water
Disharmony of Island fauna and flora
Rapid Speciation- “bursts” of new species
Pollination Relationships with surroundings
Dispersal Barrier, likely to radiate at or near the limits of the range of dispersal
Variation in feeding and mating rituals
Wide range in habitat and growth form

7. Hawaiian Islands

9. Hawaiian Island Adaptors
Hawaiian Honeycreepers
Hawaiian Fruit Flies (Drosophilidae)
Pelia
Silverswords
Cytrandia

10. Hawaiian Honeycreepers - Drepenidiae

11. Honeycreeper Radiation
Occupy an array of foraging and dietary niches which correspond with the variety of bill morphologies, variety and natural variation allowed random mutations to succeed at a higher rate because of the openness of niches during first colonization
Repeated inter-island colonization allowed allopatric differentiation, followed by sympatric reinforcement and ecological divergence because of the lack of competing species and a broad variety of ecological niches
Thought to have adapted like the Galapagose Finches, most common ancestor is thought to be the Eurasian Rose finch

12. I’IWI Vestiaria coccinea Found in the ‘ohi’a lehua forests
Feed on the nectar of ‘ohi’a lehau flowers and tubular blossoms

13. ‘APAPANE Himatione sanguinea Found in the ‘ohi’a lehau forest
Feeds primarily on nectar, also feed on insects

14. ‘AKOHEKOHE Palmeria dolei Feed mainly on nectar and seeds
Found in the rainforests of Maui
Endangered

15. PALILA Loxioides balleui
Found only on the dry forest slopes of Mauna Kea
Endangered
Feed mainly on seeds

16. ‘AKIAPOLA’AU Himignathus munroi Found only on big island of Hawaii
Endangered
Woodpecker like in they eat insect larvae by chipping away bark, also effectively eats the nectar of lobeloids

17. Hawaiian Fruit Flies-Drosophila
250 species of Drosophila are known, but numbers are expected to double
114 species of Scaotomyza on Hawaiian Islands, only 70 species are known on the rest of the world
Isolation is thought to be the main cause of new species, preference to a particular host can isolate a species to where adaptive changes may occur

18. Hawaiian Fruit Flies Con’t
Each species has individual preference for mating ceremonies and territories which involve factors of light, temperature, and humidity
Differences in food sources-
herbacous v. carniverous
Body, wing size and shape

19. Cyrtandra Has formed the most diverse species on the Hawaiian Islands
129 species on Oahu alone
Most vary in leaf and flower morphology, also fruit

20. Cyrtandra hawaienses
Cyrtandra platyphylla

21. Cyrtandra cordifola
Cyrtandra calpidecarpa

22. Geranium 50- 100 species known on Hawaiian Islands
Occupy almost all of the habitats available to them
Vary widely in leaf and bud morphology, also in growth form

23. Adaptive situations often cause plants to evolve the available pollinators, such as changing from insects to birds or vis versa

24. Overview
Adaptive radiations are the process by which plants, animals, and insects adapt to their surroundings in a way that they form new species in a relatively short period of time
Some criteria for adaptive radiation to occur is a dispersal barrier, ecological isolation, biological isolation,etc.
Evolution of the Hawaiian islands has influenced the radiation of the plants and animals over the years because the islands have been moving and changing ecologically, pathing the way for adaptive radiation to occur

25. Examples of adaptive radiations can be seen in many Hawaiian species such as the Honeycreepers, Fruit flies, and the growth forms of Cyrtandra and Geranium
Adaptive radiation is important to the Hawaiian Islands and many island alike because it increases the diversity of the wildlife, but with recent invasion of tourism and foreign plants and animals, the available area to be exploited by nature is decreasing, in turn not allowing as much diversification to occur

26. Bibliography
Carlquest, Sherwin. Hawaii: A Natural History. Honolulu: SB Printers, Inc Ch. 5.
Carr, Dr. Gerald. U of Hawaii, Botany Department.
Schulter, Dolph. The Ecology of Adaptive Radiation. Oxford U Press. Oxford, New York
Bermingham, Eldredge; Lovette, Irby J. Clade-specific Morphological Diversification and Adaptive Radiation in Hawaiian Songbirds. The Royal Society
U of Southwestern Adventist, Biology Department.