BIOL112 - Ecology (Set 2)

Lectures 20 & 21 - Aotearoa Flora and Fuana

What are endemic taxa?

Species which are naturally found only in a specific geographic area (found nowhere else).

What are native taxa?

Species which breed naturally in a given area, but are also found elsewhere.

What makes New Zealand unique?

Isolation, oceanic climates, mountainous climates, a history of major disturbances (tectonic, glacial), moderately infertile soils, last major land mass to be settled by humans.

What two categories are allopatric processes split into?

Dispersal and vacariance.

How can dispersal be defined?

Where a few members of a species move to a new geographical area.

How can vicariance be defined?

Where a natural situation arises to physically divide organisms.

What was Zelandia?

A large piece of land on earth about 80 MYA, which was low lying (94% underwater).

Zelandia was big, why is New Zealand not?

The Oligocene was a geological epoch where landmasses experienced many changes, causing the near-drowning of what we now know as New Zealand.

What saved New Zealand from drowning?

Tectonic activity.

What were the effects of tectonic activity on biota in New Zealand?

More pronounced phylogenetic patterns, along with east-west splits along the Southern Alps (in short).

How did glaciation affect New Zealand?

Influenced the expanding and shrinking of glaciers (30% of South Island), along with the rising and falling of sea levels (in short).

What can Island endemism lead to?

Really big species (gigantism), really small species (dwarfism), K-selected life histories, and unique behavioural traits.

What are r-selected species?

R-species have traits that maximise growth rates; produce many small offspring, small body size, early reproduction, rapid development, low competitive ability, and semelparity.

What is semelparity?

The ability of an organism to produce lots of offspring in one single reproductive event per life time.

What are r-selected species?

K-species have traits that maximise utilisation of resources; produce few larger offspring, large body size, reproduce later in life, slow development, high competitive ability, and iteroparity.

What is iteoparity?

The ability of an organism to produce fewer, larger offspring several times during their lifetime.

What are some patterns of unique features in New Zealand biota?

Ancient lineages and prehistoric traits, extremely long migration or none at all, giant or tiny in size, convergent evolution, k-selected traits, flightlessness, nocturnal, lack of fear (of mammals).

How is it thought that tuatara evolved to be in New Zealand?

Through vicariance.

How is it thought that ngaokeoke evolved to be in New Zealand?

Through vicariance.

What does radiation refer to in terms of ecology and is this prevalent in Aotearoa?

When groups are species rich, and yes, this does occur in many New Zealand lizards (though it can go the other way).

(Unusual animal features) why has flightlessness evolved and why is it so common in New Zealand?

Becayse of the lack of predators for some species, the resistance to predators for others, and the aquatic environments many species are found in.

(Unusual animal features) why do New Zealand birds show little fear towards mammals?

New Zealand birds evolved without land mammals for a long time, therefore they do not have an innate fear of introduced land mammals.

(Unusual features) how do strong odours effect New Zealand birds?

Odours on New Zealands native birds are attracting predators.

(Unusual features) what is convergent evolution?

Where similar characters evolve independently in two species in response to similar selective pressures; for example, some birds can fill the niches of mammals.

(Unusal features) how do life histories differ in New Zealand?

Most species here show life histories suited to a low-predation environment, meaning they are k-selected, e.g. kakapo.