1. CONSERVATON BIOLOGY Lecture04 – Spring 2016 Althoff - reference Chapters 6-10 THREATS TO BIODIVERSITY Part I

2. Threats…Overview ______________________________

3. Mass Extinctions Biodiversity has risen, fallen, risen, fallen, risen, fallen, etc. in the last 600+ million years (as indicated here fossil record of marine organisms) There has clearly been a ______________!!!!

4. Mass Extinctions ___ recognized “mass” extinctions 1 2 3 4 5

5. Some key points….GOOD NEWS Overall trend for biodiversity is ____ Mass extinctions just “____________” setbacks Life on earth has ______________ from microbes to magnificent creatures (think sharks, bees, eagles, lions, tigers, and bears—oh my!) _______ meteorites, volcanoes, and glaciers…the earth’s biodiversity has not returned us to “just microbes.” Despite the threat of, say a nuclear holocaust (or even with it), life on earth in some form is _______ ___________________

6. Some key points….BAD NEWS Recoveries—from mass extinctions—typically have taken _____ of millions of years each time. If things are as bad as some biologists have suggested they are….meaning we are in the midst a human- caused extinction “spasm” comparable to any of the 5 prior mass extinction events, then _____ of the X- number (100s? 1,000s? 10,000s?) of generations of humans that follow will witness the recovery …thus, last point begs for us to do all we can to not make the 6 th major extinction event human-caused!

7. Current Rates of Extinction Difficult to estimate—although many do try to Why? 1) hard to say for sure that a species ____ become extinct. More cryptic, more remote areas, more difficult to assess: ex. Cahow (rare seabird)…disappeared in 1621, not recorded again ‘til 1906 ex. Ivory-billed woodpecker…last verified in the 1940s in US, 1987 in Cuba (subspecies)…again in 2004??? 2) Most of species of the world _______ identified and described (~85-99%)…. thus many not yet identified have gone extinct

8. Known extinctions since 1600 Molluscs303 Crustaceans 9 Insects 73 Other invertebrates 4 Fishes 92 Amphibians 5 Reptiles 22 Birds131 Mammals 87 Mosses 3 Gymnosperms 1 Angiosperms Dicots 83 Monocots 3

9. E.O. Wilson estimates…. _______ species going extinct per year (see p120 text) Considered conservative number…as it only considers tropical forest (with high diversity), and because assumes species have fairly broad geographical ranges ____________ is a “typical” life span for a species If human pop n stablizes between 10-15 billion in next 50-100 years AND loss of ecosystems stabilize…. _______ of our biota could be lost. Without curbing pop n growth & consumption of resources….25% figure is considered optimistic

10. Climate Change Changes in the geographic ranges of two tree species…responding _______________ of one another. (Ka = 1,000 years ago). Point????

11. One key: How well can a species “shift” its geographic range? MOBILE AS INDIVIDUALS migratory, early-successional bird Insects of ephemeral ponds pelagic fishes SEDENTARY AS INDIVIDUALS territorial fishes with planktonic larvae early-successional plants; self-incompatible annuals intertidal molluscs ________ between generations

12. One key: How well can a species “shift” its geographic range? MOBILE AS INDIVIDUALS migratory, philopatric birds insects of deep lakes anadromous fishes SEDENTARY AS INDIVIDUALS desert-spring fishes late-successional plants; self-compatible perennials terrestrial molluscs ________ between generations

13. Evidence for temperature-dependent biological phenomena ____________ phenomena: examples include a) earliest known flowering dates of plants b) first calling dates for frogs Based on 143 long-term studies conducted around the world, ______________of the species are shifting (aka “moving up”) in the direction expected on the basis of known _____________ constraints if, indeed, climate warming was influencing them. These “shifts” are moving ahead, on average, by __ ____________ over the past century.

14. Root, T.E., J.T. Price, K.R. Hall, S.H. Schneider, C. Rosenzweig, and J.A. Pounds. 2003. Fingerprints of global warming on wild animals and plants. Nature 421:57-60.