3.2 Origins of Biodiversity Flashcards
Wallace Line
Named for Alfred Wallace. To the west of the Wallace Line, the islands are characterized by fauna and flora that are predominantly Asian in origin. To the east, the islands host a mixture of Australian-origin species like marsupials.
Landbridge
Areas which at times have been above sea level and navigable by terrestrial fauna.
Endemic/Endemism
Occurring nowhere else on Earth.
The % endemism of a place is the proportion of unique species.
Placental
A class of mammal which give birth to live young (which develop inside the womb and are nourished through a placenta). From an evolutionary standpoint, placentals babies are subject to fewer environmental pressures than marsupials.
Galapagos Finch
The text-book example of adaptive radiation. They evolved different beak shapes and sizes to best match the food resources available on their islands.
Galapagos Islands
A volcanic archipelago in the Pacific Ocean. Often studied for its contribution to evolutionary theory.
Madagascar
An African island on which lemurs undertook evolution to adapt to take advantage of a variety of trophic and habitat niches.
Survival of the Fittest
A concept associated with evolutionary biology in which only those organisms best adapted to their environments successfully procreate and pass their genes to successive generations.
Natural Selection
The concept associated with evolutionary biology which explains how traits become more or less common in a population over time based on the reproductive success of organisms with those traits.
More correct to use than “survival of the fittest”
Evolution
How an organism changes over successive generations to adapt to available resources and conditions.
Can occur through mutations or natural selection.
Why are so many of New Zealand’s birds flightless
They evolved in the absence of other mammals or reptiles to occupy available niches, including terrestrial ones, and were successful owing to the absence of predators.
Geographic Isolation
A barrier (natural or manmade) which prevents genetic flow between populations and can lead to speciation (development of separate species).
Speciation
The evolution of populations of the same species separated by a physical barrier into two different species that cannot successfully interbreed.
Pangea
The supercontinent. Split into Gondwanaland (South America, Africa, Australia and Antarctica) and Laurasia (North America, Europe and Asia) 175 million years ago.
Gondwana and Laurasia
Gondwana(land) is the supercontinent comprising of South America, Africa, Australia, Antarctica and India (separated from Pangea 175 million years ago)
Laurasia comprises of Asia and North America.
Temporal Isolation
When two organisms or populations are separated due to the time of day they are active. Similar to behavioral isolation.
Inheritance
The passing down of genetic material from one generation to the next.
Niche
refers to the role or function of an organism or species within an ecosystem, encompassing its relationships with other living organisms and its interactions with the physical environment.
Arboreal (vs terrestrial)
Arboreal means “in the trees”.
Terrestrial means “on the ground”.
Trophic niche (vs habitat niche)
A trophic niche is where an organism fits in the food chain. Relates to what they eat and what eats them.
A habitat niche refers to where an organism lives (the space it occupies).
Extinction
Death of the last individual of a species.
