OEB 190 Biogeography

Final

The "Sarawak Law" (1855)

Every species has come into existence coincident both in space and time with a pre-existing closely allied species

the father of biogeography

Alfred Russel Wallace

Biogeography vs Taxonomy

Biogeography: the distribution of life on earth

Taxonomy: how we organize the diversity of life

Most evolutionarily unique biogeographic regions

Australian region

Paleognathous palate vs Neognathous palate

palatines are lateral in paleognathous

palatines are medial in neognathous

Moa molecular data suggests that

1) possessed a full repertoire of olfactory receptor genes

2) could see in the UV range

The supercontinent Gondwana contained

most of today’s Southern Hemisphere continents, such as South America, Africa, Antarctica, Australia, India, Arabia, and Madagascar

Continental drift and ratite biogeography

pattern lines up strikingly well with the breakup of the ancient supercontinent Gondwana

Palaeognaths and flight loss relationship

Evolved flight loss many times

how are Flamingos and grebes related

sister groups

Different recognized clades

Waterbirds (pelican, cormorant, alabatros, ibis)

Higher land birds (motmot, toucan, woodpecker)

based on what?

Syrinx

3 lineages of perching birds

Subossines

• Tyranni

Ossines (complex syrinx/ learning capacity)

• Corvida

• Passerida (double fossa of humerus)

Basal lineages of extant clades often have what? Example?

Gondwanan distributions

• Ie. Magpie Goose in Australia / New Guinea

• ie. Orange-footed scrubfowl in Australia / New Guinea

Importance of New Zealand in global biogeography of bird

1. Long isolation = evolutionary “time capsule”

2. Survival of basal passerines (perching birds)

   1. ie. Rifleman, Kiwis, Kokapo

Oligocene hummingbird fossil in Germany / France

overturn the simple idea that hummingbirds “originated and stayed” in the Americas

• reveal a once-global lineage that later became geographically restricted

Haast’s Eagle fossil evidence suggests what? what evidence?

may have been a scavenger

• evidence: very large, powerful, tearing beak, comparable in some ways to modern scavenging raptors.

Zealandia is thought to have undergone..

Oligocene Drowning (~25 mya)

Bird lineages in New Zealand show divergence times older than Oligocene Drowning, what does this suggest?

1. “Not fully drowned” (partial refugia)

2. Overwater dispersal happened earlier than assumed

Connections between the Neo- and Paleotropics? Examples?

biogeographic connection between tropical regions of the world, most likely shaped by historical dispersal across once-connected or climatically favorable routes, followed by isolation into New World and Old World lineages.

• Trogons

• Barbet / Toucan

Breakup of Gondwana relation to passerine split

Late Paleogene (66 – 49 Ma)

• New Zealand - Acanthisitta

Early Eocene (60 – 45 Ma)

• oscine/subsoscine split

Later Eocene (50 – 37 Ma)

• NW and OW Suboscine split

Subossine route into the New World

Subossines from bottom of South America (earlier arrival)

• New World suboscine radiation (antsrhikes, tityras, manakins, cotingas, woodcreepers, flycatchers)

• explains why suboscines are dominant in South America

Ossine route into the New World

Ossines from Canada and alaska

• Evolved mainly in Australia/New Guinea

  • ie. Australian Corvidae radiation

• Later spread globally, including into the Americas

major divisions within oscine passerines

Pneumatic fossae of the humerus

Latitudinal gradient in passerines, suboscines, and oscines.

Northern and southern limits of ranges

What are Transmitting tags? What do they do?

Satellite tags can give scientists a highly detailed look at migratory journeys

Population models can use different data sources from

• transmitting tags

• banding

• ebird

Common misconception about migration direction

not always north to south, can be east to west

• also many species that breed on mountains migrate downslope after breeding

2 ways to understand migration

1. Escaping the snow to spend winter in the warm tropics (“Northern home”)

2. Escaping the competitive tropics to breed in a land of abundance (“Southern home”)

   1. assumes tropics are competitive

migration is the outcome of…? How does this relate to plants?

a tradeoff between competition and mobility

• “Strong” competitors hold their ground while “weak” competitors move around

Southern Home hypothesis

Prediction 1: Migrants that evolve out of the tropics should have close relatives there

Prediction 2: If migration evolves from resource hunting, then migration should appear more commonly in more nomadic and dispersive lineages

philopatric

tendancy to return to exact same area

Why might Northern and Southern home hypothesis be a false dichotomy

Because many migrants are intensely philopatric to both breeding and wintering areas….and even migratory stopover sites

• so it is all home

• ie. Whimbrels have same feeding sites

What is the Cox model?

Explains the the evolution of Neotropical migration

• Migrants wintering in northern fringe of tropics expand niche seasonally due to untapped resources of north. Increased competition causes migration evern further north resulting in north migration in breeding season.

Levey-Stiles model for the origin of migration: Ecological correlation to migration

Ecological correlates of altitudinal migration in Costa Rican birds

• fruit and nectar feeding birds more likely to be altitudinal migrants

Levey-Stiles model for the origin of migration: Microhabitat correlation to migration

canopy edge birds more likley to be altitudinal migrants

Examples for Levey-Stiles model

Flycatchers, Hummingbirds, Caprimulgiformes

Exceptions to Levey-Stiles model

Parulidae, Pewees (specific type of flycatcher)