Chapter 12 and 13 April 16, 2012

Domestication – process by which plant and animals species come to depend on humans for survival while providing humans with some benefit teosinte

Humans and Extinction Humans are responsible for 6 th extinction on Earth –Predation –Trophic cascades –Alien species –Habitat destruction –Agriculture Prehistoric extinctions Historic extinctions

Easter Island palm (Paschalococos disperta) »Chilean wine palm Historic Extinctions

Iceland - northern birch (Betula pubescens)

Historic Extinctions Omilteme cottontail Great auk

Historic extinctions of small, endemic populations Passenger pigeon – 5 billion killed Tasmanian tiger Historic Extinctions Passenger pigeon

Pandemics and Endemics Pandemics – having a widespread distribution between and within biogeographic regions Endemics – restricted to 1 geographic area Neoendemics – species that just recently evolved Paleoendemics – endemics that had a much larger range in the past

Silversword (Argyroxiphium sandwicense sandwicense) Redwood (Sequoia sempervirens)

Distribution Types Dispersal disjunctions – when a jump dispersal event allows a population of a plant or animal species to become established a long distance from the main population Least bittern (Ixobrychus exilis) Figure 13.7

Climatic disjunction – occurs when climatic change makes a portion of a species’ range uninhabitable and splits a once continuous distribution Distribution Types Figure 13.7 Magnoliaceae family

Climatic Disjunction Gorilla (Gorilla gorilla)

Geologic disjunction – when geologic processes split once continuous ranges into two or more separate parts Distribution Types Superorder Ratites

Evolutionary disjunction – when 2 new species develop in different portions of the geographic range of a widespread common ancestor Distribution Types

Biogeographic Relicts Biogeographic relicts are taxa that once had larger distributions but have become narrow endemics –Climatic relicts – species whose geographic ranges are restricted due to recent climate changes – aka glacial relicts Torrey pine (Pinus torreyana)

–Evolutionary relicts – paleoendemics that are survivors of formerly more widespread and diverse evolutionary lineages Biogeographic Relicts Tuatara (Spenodon punctatus)