Biology 1229

Extinction

Extinction“the cessation of existence of a

species”

IUCN categoriesExtinct

No reasonable doubt that the taxon is gone.

717 animal and 87 plant species since 1500

Lytta mirifica

huia

Labra

dor

duck

Ste

ad’s

Bush

Wre

n

Gre

at

Auk

Thyla

cine

Steller’s Sea CowPassenger Pigeon

dodo

Quagga

IUCN categoriesExtinct in the wild

Species only exists in captivity or cultivation

37 animals and 28 plants

Extinct in the wild

St Helena Redwood Wood’s Cycad

Hawaiian Crow

Redtail Shark Black-footed ferret

Partula snails

IUCN categoriesCritically endangered

Extremely high risk of extinction in the wild

3240 species (up from 3124 in 2007 and 3071 in 2006)

Includes 6 species of fungi

Baiji

North American Burying beetle

South

ern

Blu

efin T

una

Black Rhino

Kakapo

IUCN categoriesEndangered

Very high risk of extinction in the wild

4768 species

IUCN categoriesVulnerable

High risk of extinction in the wild8911 species

IUCN categories Near Threatened

Ongoing conservation measures required to prevent risk of extinction

3513 Least concern

Widespread, abundant & safe 17675

Data deficient No assessment possible 5561

Gaps in knowledgeAlmost all invertebrates

Apart from ‘showy’ ones Collected beetles Butterflies Dragonflies

Poor knowledge of tropics, esp. in Africa

The vast majority of described species are known from only a few specimens

A Global Extinction Crisis>33% of frogs threatened¼ of Mammals face extinction15-37% of species extinct by

205070% of Butterfly species in

decline

Why should we care?The sadness of losing biodiversityOur moral responsibilitiesEcosystem services

Ecosystem servicesAll the free stuff we get from

nature Water purification, decomposition,

dung removal, pollination, O2 repletion, CO2 absorption, food, pharmaceutical products etc.

$16-54 Trillion (i.e. $16 000 000 000 000) per year… in 1997!

Why do species go extinct I?Natural extinctions

Population changes Natural disasters Evolution, migration and habitat

change

Why do species go extinct II?Anthropogenic influence

Habitat destruction

Invasive speciesOverkill

Climate Change

The four horsemen of the extinction crisis I: Habitat destruction

The four horsemen of the extinction crisis II: Overkill

The four horsemen of the extinction crisis III: Invasive species

Stoat (NZ)

House Mouse (Many places!)

Red F

ox (

Aust

ralia

)

Bru

sh-t

aile

d p

oss

um

(N

Z)

Rhododendron (Scotland)Emerald Ash Borer (SW ON)

NZ Flatworm (Ireland)

Zebra Mussel (Great Lakes)Eu

ropean

Sta

rlin

g

(Many p

lace

s!)

The four horsemen of the extinction crisis IV: Climate change