Biodiversity Chapter 12

Biodiversity Biodiversity - the variety of living things - three types essential: Genetic diversity - variety of different versions of the same genes within a species Species diversity - number of different kinds of organisms within an ecosystem Ecological diversity - complexity of a biological community (number of niches, trophic levels, etc.) Adding to the concept of biomes, we now want to consider the concept of biodiversity (how varied living material is in a system). There are three basic kinds of biodiversity. The most commonly used is species biodiversity. However, within any species there can be a large or a relatively small amount of genetic diversity. For instance, let's consider two different species. First, let's take a species of wasp that feeds only on the pollen of one particular flower located in a very small part of a tropical rain forest. The wasp would die out if the flower were not present. The wasp is probably a species that exhibits a small amount of genetic diversity. We could also consider a species like Douglas-fir that is found all the way from British Columbia down to southern California. and also lives in two very different types of temperature and moisture regimes. For instance, it lives in both western and eastern Washington. Western Washington is cooler and wetter in the summer than eastern Washington, where it gets very hot and dry. We can conclude from its wide and varied distribution that Douglas-fir is a species with a lot of genetic diversity. We can also have ecological diversity, which consists of the niches or functions that species display within an ecosystem. If those are diverse, the system could be considered diverse as well. If we have a number of species that effectively do the same thing within an ecosystem, the ecosystem would not be as ecologically diverse as one in which organisms had a variety of ecological roles. It is easier to just count species as a measure of biodiversity, and this is probably why the common use of the term biodiversity refers to this measure.

Is there an equal distribution among groups of organisms? Current Estimates of Known Living Species by Taxonomic Group (IUCN, 2005) Mammals 5,416 Birds 9,917 Reptiles 8,163 Amphibians 5,743 Fishes 28,500 Insects 950,000 Mollusks 70,000 Crustaceans 40,000 Other invertebrates 130,200 Ferns, mosses, and lichens 38,025 Gymnosperms 980 Grasses 59,300 Flowering plants 199,350 TOTAL 1,545,594 How many species exist? Is there an equal distribution among groups of organisms? There are big questions in the study of biodiversity. Perhaps the biggest is just how many species there are. Some species are easily identified (flying birds, and plants such as Douglas-fir). Others, particularly small organisms that aren't easy to see, and organisms that live in environments that humans don't often visit, are much more difficult to count. In particular, if we take the insects, we find that they are incredibly diverse; and so it is very difficult to catalogue all of them. We have only scratched the surface of the number of species that exist, but we recognize that over a million species have been identified so far. This is probably only a fraction of the species that exist, particularly for poorly characterized organisms like insects and mites. The estimates for mammals and birds are stable (it is rare to discover a new species in these groups today), so there are probably fairly good estimates of the number of species that exist today. Another question that needs to be asked in making tallies of species is, "What exactly constitutes a species"? IUCN - International Union for Conservation of Nature

Biodiversity Hotspots Most of the world's biodiversity concentrations are near the equator (tropical rainforests, coral reefs).

Biodiversity through time Biodiversity is not stable through time Extinction common phenomenon natural process - one species lost every 10 years accelerated by human impacts on populations and ecosystems E.O. Wilson - we are currently losing thousands of species a year Dynamic earth/solar system process results in changes of climate & land masses

Changes Through Time

The Dynamic Earth The earth’s continents are on plates These continental plates rest on liquid (mantle) and continue to shift The present-day arrangement of the plates (continents) has not always been so…….

Continential Drift 225 million years ago 135 million years ago present

Geologic Time is measured with Extinction Events: six major extinction episodes - we are living the 6th What role does extinction have on biodiversity? 6. Current Extinction Crisis: caused by human activity 5. Cretaceous: ruling reptiles (dinosaurs); many marine species 4. Triassic: 35% of animal families, including many reptiles and marine mollusks 3. Permian: 50% of animal families, including 95% of marine species; many trees, amphibians, etc. 2. Devonian: 30% of animal families 1. Ordovician: 50% of animal families

Adaptive Radiation of organisms if habitat remains, mass extinction can lead to rapid evolution due to vacated ecological roles left by extinct species one example is the mammal “explosion” in the Cenozoic

Species Decline after human contact hoofed animals flightless birds

Causes of Extinction - HIPPO 1. Habitat loss 2. introduction of Invasive (non-native) species problems arise from competition (exotic out-competing natives) 3. Pollution 4. Population (human) 5. Overharvesting

What value is Biodiversity? Research and education value Recreational Value Intrinsic Value Aesthetic Value Life support Value Economic Value

What habitats are in peril? Endangered and Threatened Species Worldwide from IUCN Red List, 2014 (with % of total) Mammals 1,199 (26%) Birds 1,373 (13%) Reptiles 397 Amphibians 1,957 (40%) Fish 2,222 Insects &other invertebrates 4,140 Total Fauna 11,288 Plants (Flora) 10,595 (40%) four habitats in particular tropical rain forest estuaries wetlands coral reefs This slide shows the number of endangered and threatened species worldwide that are listed by the US Fish and Wildlife Service. You'll notice that hundreds of species of animals and plants are presently listed as endangered or threatened. This shows that the potential for extinction of many of these species is there. Many of their problems are being addressed, but many are not. International Union for Conservation of Nature

Habitat Loss: tropical rain forest less than 1/2 exists today perhaps all gone by 2030 7% of land mass 50% of species complex and biodiverse poor soil, since 90% of nutrients are contained as biomass

Habitat Loss: estuaries Pacific Northwest bays where rivers empty into the sea mix fresh and salt water calm, warm, nutrient-rich 65% of marine fish and shellfish use estuaries and saline wetlands for spawning and juvenile development help stabilize shoreline and reduce storm damage inland Chesapeake Bay

Habitat Loss: wetlands shallow ecosystems saturated or submerged land surface support rich biodiversity migrating waterfowl 1/3 of all endangered species spend part of their lives in wetlands retain storm water and reduce flooding filter/purify urban and farm runoff swamps wetlands with trees marshes wetlands without trees bogs water-saturated ground ground composed of deep layers of accumulated, undecayed vegetations known as peat less biologically diverse, yet unique species reside fens bogs fed by groundwater

Habitat Loss: coral reefs among the most species-rich and productive ecosystems in the world reefs are colonies of small colonial animals (polyps) that live symbiotically with photosynthetic algae 60% of world reefs are at risk from human activities

Strategies for Conserving Biodiversity Read carefully pages 470-476 develop an answer to the question: Describe different strategies for conserving biodiversity from global to local levels.

Island Biogeography What happens to species number as the island gets further away from source pool? species # as distance of source pool  What happens to species number as the island gets smaller? species #  as surface area  study of facts and patterns of species distribution in/on islands two important variables to consider island’s distance from a source pool of species surface area of an island

Island Biogeography So, what would you predict in the Wisconsin forest example?

National Parks as Isands

Conserving Biodiversity Population biology principles (p. 465) small populations of a species are more likely to become extinct than large populations easier to prevent “endangered status” than “endangered” to extinct to understand a population, important to consider age structure and sex ratio populations must be monitored to determine the effects of a conservation plan on the status of a species

Conserving Biodiversity Conservation biology principles (p. 466) species less likely to become extinct if broadly distributed across its range habitat characteristics favoring species preservation: large rather than small in size close together rather than widely separated whole rather than internally fragmented linked by “corridors” rather than isolated broad rather than long and narrow inaccessible rather than easily accessible to people

Applying Island Biogeography read pages 464-469 Answer question #1, p. 469 Answer question #2, p. 469 Answer question #3, p. 469