1. Fossils & Evolution—Chapter 81 Chapter 8—Stuff to know Marine bathymetry zones –Neritic / bathyal / abyssal / hadal Environmental limiting factors (know all) –Salinity categories –Stenohaline /euryhaline taxa Evolutionary paleoecology –tiering; escalation;

2. Fossils & Evolution—Chapter 82 Chapter 8—Paleoecology Ecology = the study of the interactions between organisms and their environment Paleoecology = ecology applied to the study of fossils and ancient environments Evolutionary paleoecology = study of ecologic phenomena that operate on the scale of millions of years (and are invisible to ecologists of the living biota) Main applications of paleoecology are in (1) reconstructing ancient depositional environments and (2) assessing environmental influences on evolution

3. Fossils & Evolution—Chapter 83 Marine ecosystem Modern marine ecosystem is used by paleontologists as an analogue for ancient marine ecosystems Drawbacks to uniformitarian approach –Past climates generally have been warmer than today’s –Past sea levels generally have been higher than today’s Few modern epicontinental seas No modern tropical epicontinental seas

4. Fossils & Evolution—Chapter 84 Devonian (360 Ma)

5. Fossils & Evolution—Chapter 85 Marine bathymetry zones Neritic = continental shelf (from sea level to ~200 m) –Intertidal –Subtidal zone Bathyal = continental slope and rise (from ~200 m to ~2000 m) Abyssal = deep ocean floor (from ~2000 m to ~ 6000 m) Hadal = very deep ocean (> 6000 m) Photic zone = depth to which light penetrates –Highly variable, depending on water clarity –Photosynthesis usually takes place in upper 100 m of water column

6. Fossils & Evolution—Chapter 86 Marine environments

7. Fossils & Evolution—Chapter 87 Ecologic limiting factors = physical, chemical and biologic properties of the environment that limit the distribution and abundance of a particular species –Temperature –Oxygen –Water depth and depth-related variables –Salinity –Substratum –Food

8. Fossils & Evolution—Chapter 88 Limiting factors: Temperature Probably the single most important limiting factor governing large-scale distributions (biogeographic provinces)

9. Fossils & Evolution—Chapter 89 15°C Modern symbiont-bearing corals and foraminifers occur mainly in water that is warmer than 15°C (winter sea surface temperature)

10. Fossils & Evolution—Chapter 810 Limiting factors: Oxygen Black Sea: direct relationship between dissolved oxygen in water and faunal diversity –As dissolved oxygen decreases with increasing depth, so too does diversity –First animals to disappear are large, heavily calcified invertebrates –Small, weakly calcified to uncalcified taxa extend to greater depths (taxa unlikely to be preserved as fossils)

11. Fossils & Evolution—Chapter 811 Limiting factors: Oxygen soft-bodied

12. Fossils & Evolution—Chapter 812 Limiting factors: Oxygen

13. Fossils & Evolution—Chapter 813 Limiting factors: Water depth Depth, in and of itself, exerts very little influence over distribution of organisms, but depth-related factors are very important –Hydrostatic pressure –Light wavelength and intensity –Salinity –Temperature –Nutrients –Dissolved oxygen

14. Fossils & Evolution—Chapter 814 Limiting factors: Water depth (light) Light is attenuated as it penetrates through water –Intensity of light decreases –Different wavelengths of light are absorbed at different rates green algae use red light red algae use blue light

15. Fossils & Evolution—Chapter 815 Limiting factors: Salinity Stenohaline species have little tolerance for salinity fluctuations Euryhaline species have greater tolerance for salinity fluctuations Termsalinity (‰) Freshwater 0–0.5 Brackish 0.5–30 Seawater 30–40 Hypersaline 40–80 Brine > 80

16. Fossils & Evolution—Chapter 816 Limiting factors: Salinity Stenohaline groups include: –Corals, cephalopods, articulate brachiopods, and echinoderms Euryhaline groups include: –Inarticulate brachiopods (Lingula), pelecypods, gastropods, and ostracodes

17. Fossils & Evolution—Chapter 817 Evolutionary paleoecology Evolutionary paleoecology = study of ecologic phenomena that operate on the scale of millions of years (and are invisible to ecologists of the living biota)

18. Fossils & Evolution—Chapter 818 Evolutionary paleoecology Tiering = degree to which organisms in a community occupy/exploit different levels above and below the sea bottom –Partitioning of space above the seafloor increased in Ordovician time with advent of tall crinoids, etc. –No equally tall filter feeders since Jurassic time –Partitioning of space below the sea bed increased in Late Paleozoic time (and continues to this day) –end-Permian extinction caused a temporary reduction in tiering (throw-back to Precambrian)

19. Fossils & Evolution—Chapter 819 Tiering: infaunal tropical shrimp

20. Fossils & Evolution—Chapter 820 Tiering: tall crinoid

21. Fossils & Evolution—Chapter 821 Tiering

22. Fossils & Evolution—Chapter 822 Evolutionary paleoecology Escalation = “arms race” in the evolution of predation and defense capabilities –Triassic increase in kinds of shell-crushing predators led to decline of lightly protected shellfish and preferential survival of forms with robust shells, burrowing, swimming, or other defense adaptations

23. Fossils & Evolution—Chapter 823 Evolutionary faunas weakly skeletonized taxa (e.g., trilobites) and few predators increase in calcification of skeletons, but fauna dominated by sessile filter-feeders modern fauna dominated by taxa with robust shells and/or burrowing, swimming, or other defense adaptations

24. Fossils & Evolution—Chapter 824 Predation scars on gastropod shell

25. Fossils & Evolution—Chapter 825 Escalation: increase in “crushers” through time

26. Fossils & Evolution—Chapter 826 Escalation: decrease in umbilicate and/or thin-shelled snails through time

27. Fossils & Evolution—Chapter 827 Escalation: increase in heavily fortified snails through time