Myth 3: Extinction Is Unnatural and Bad, But Easy to Accomplish — Key Concepts

A set of vocabulary flashcards covering the major concepts and examples from the notes on extinction myths, the role of humans, key extinct and recovering species, and strategies in ecological engineering and conservation triage.

Extinction (natural)

The ultimate fate of all species in a finite universe; extinction is natural and inevitable for all species over time.

Sixth Extinction

The current biodiversity crisis attributed largely to human actions, predicted to be the most devastating extinction event since the asteroid impact; described as ‘the cataclysm is us.’

Mega-extinctions

Five mass extinction events in roughly 550 million years of multicellular life, with the Permian–Triassic event being the largest (about 80–90% of species lost).

50/500 rule

A historical guideline for declaring a species endangered: population dropping below 50 individuals in the short term or below 500 in the long term signals endangered status due to genetic inbreeding; has notable limitations.

Passenger pigeon

Once extremely abundant (potentially 3–4 billion birds), whose rapid decline and extinction by 1914 illustrate how social behavior and human hunting can drive a species to extinction despite previous abundance.

Whooping crane extinction probability

A mathematical estimate showing very low extinction risk under historical variability; for example, a past calculation suggested a 5 in 1 billion chance by a future date under certain assumptions.

Elephant seals (recovery)

Nineteenth-century hunting nearly drove northern elephant seals to extinction; protection led to a rebound to numbers over 60,000 by the late 20th century.

Sea otters (recovery)

Severe historical declines due to hunting; protection since the early 20th century has led to population recovery to over 100,000, though some subpopulations remain threatened.

Sandhill cranes (protection and recovery)

Protected under the 1916 US–Canada Migratory Bird Treaty; populations grew from vulnerable levels to hundreds of thousands, though numbers fluctuate.

Golden toad (extinction cause)

Costa Rica’s Monteverde habitat specialist; decline linked to habitat loss, climate variation (El Niño/global warming), and likely chytrid fungus (Bd) as a disease driver.

Po‘o-uli (Hawaiian honeycreeper)

Maui, Hawaii bird whose habitat loss and invasion by disease-carrying mosquitoes, plus rats and mongooses, led to its extinction by the late 20th century.

Javan tiger

Indonesian island tiger subspecies driven to extinction by habitat loss, hunting, and competition, with the subspecies now considered extinct or nearly so.

Ecological engineering

Treating conservation like engineering: diagnose what’s broken in ecosystems, monitor populations, and apply tools and interventions to fix problems and protect habitats.

Triage in conservation

Dividing species into three groups: those likely to go extinct regardless, those that will persist regardless, and those that might persist only with help.

Role of science in endangered species decisions

Science provides some guidance but is often limited by data gaps, political and economic factors, and the complexity of ecosystems.

Habitat size and disease risk as predictors

Smaller, fragmented, or highly specialized habitats are more vulnerable to extinctions; disease and invasive species further threaten small habitats.

Human arrogance vs. capability

The idea that humans might control all life is questioned; instead, we should focus on what is practical and possible to save given limited resources.

Ethical responsibility to other life

There is an ethical argument to avoid harming other species and to act with care toward ecosystems, rather than assuming full dominance over life on Earth.

Why not save every species? resources and practicality

There are limits in time, money, energy, and interest, so conservation must prioritize and sometimes employ triage rather than attempting to save all species.