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Biodiversity and Endangered Species

Biodiversity and Endangered Species. ORIGINS OF LIFE. 1 billion years of chemical change to form the first cells, followed by about 3.7 billion years of biological change. Biological Evolution. Led to the variety of species we find on the earth today. Figure 4-2.

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Biodiversity and Endangered Species

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  1. Biodiversity and Endangered Species

  2. ORIGINS OF LIFE • 1 billion years of chemical change to form the first cells, followed by about 3.7 billion years of biological change.

  3. Biological Evolution • Led to the variety of species we find on the earth today. Figure 4-2

  4. How Do We Know Which Organisms Lived in the Past? • Fossils • Chemical analysis • Ice cores drilled out of buried ice • DNA analysis

  5. EVOLUTION, NATURAL SELECTION, AND ADAPTATION • Biological evolution by natural selection involves the change in a population’s genetic makeup through successive generations. • genetic variability • Mutations: random changes in the structure or number of DNA molecules in a cell that can be inherited by offspring.

  6. Limits on Adaptation through Natural Selection • A population’s ability to adapt to new environmental conditions through natural selection is limited by its gene pool and how fast it can reproduce. • Humans have a relatively slow generation time (decades) and output (# of young) versus some other species. • What species would evolve very fast? Bacteria • Evolution through natural selection is about the most descendants. • Organisms do not develop certain traits because they need them. • There is no such thing as genetic perfection.

  7. SPECIATION, EXTINCTION, AND BIODIVERSITY • Speciation: when a new species forms. • A new species can arise when member of a population become isolated for a long period of time which is called geographic isolation. • Genetic makeup changes, preventing them from producing fertile offspring with the original population if reunited which is called reproductive isolation.

  8. Biodiversity – variety of different species • Species Diversity – Number of different species and their relative abundances in a given area. • Genetic Diversity – Variety in the genetic makeup of organisms of a species that allow the species to reproduce and gain a competitive advantage. • Ecosystem Diversity – Variety of forests, deserts, grasslands, oceans, lakes, etc.

  9. Hybridization and Gene Swapping: other Ways to Exchange Genes • New species can arise through hybridization. • Occurs when individuals to two distinct species crossbreed to produce an fertile offspring. • Some species (mostly microorganisms) can exchange genes without sexual reproduction. • Horizontal gene transfer

  10. GEOLOGIC PROCESSES, CLIMATE CHANGE, CATASTROPHES, AND EVOLUTION • The movement of solid (tectonic) plates making up the earth’s surface, volcanic eruptions, and earthquakes can wipe out existing species and help form new ones. • The locations of continents and oceanic basins influence climate. • The movement of continents have allowed species to move. • Asteroids and meteorites hitting the earth and upheavals of the earth from geologic processes have wiped out large numbers of species and created evolutionary opportunities by natural selection of new species.

  11. 225 million years ago 225 million years ago 135 million years ago 65 million years ago Present Fig. 4-9, p. 86

  12. Geographic Isolation • …can lead to reproductive isolation, divergence of gene pools and speciation. Figure 4-12

  13. Climate Change and Natural Selection • Changes in climate throughout the earth’s history have shifted where plants and animals can live. Figure 4-10

  14. Why Should We Care About Biodiversity? • Use Value: For the usefulness in terms of economic and ecological services. • Nonuse Value: existence, aesthetics, bequest for future generations. Figure 9-5

  15. Importance of Diversity • Stability- stable environment • Genetic reserves- genetic diversity • Medicinal- medicines • Agricultural- food • Industrial- building homes; things we use • Scientific- experimental; new technology • Aesthetic- beautiful • Ethical- what should we do regarding the environment • Religious- religious beliefs regarding environment

  16. HUMAN IMPACTS ON TERRESTRIAL BIODIVERSITY • We have depleted and degraded some of the earth’s biodiversity and these threats are expected to increase.

  17. Endangered Species History of Extinctions • Extinctions have existed long before humans had an influence However: • The current extinction crisis is the first to be caused by a single species- US! • This is happening faster than ever; a few decades versus thousands to millions of years. • Humans are eliminating not only the species but, the environment. Ex. Tropical rainforest

  18. Extinction: Lights Out • Extinct- complete disappearance of a species from Earth. • Ex. Dinosaurs • Extinction occurs when the population cannot adapt to changing environmental conditions. • The golden toad of Costa Rica’s Monteverde cloud forest has become extinct because of changes in climate. Figure 4-13

  19. Species and families experiencing mass extinction Bar width represents relative number of living species Millions of years ago Era Period Extinction Current extinction crisis caused by human activities. Many species are expected to become extinct within the next 50–100 years. Quaternary Today Cenozoic Tertiary Extinction 65 Cretaceous: up to 80% of ruling reptiles (dinosaurs); many marine species including many foraminiferans and mollusks. Cretaceous Mesozoic Jurassic Extinction Triassic: 35% of animal families, including many reptiles and marine mollusks. 180 Triassic Extinction Permian: 90% of animal families, including over 95% of marine species; many trees, amphibians, most bryozoans and brachiopods, all trilobites. 250 Permian Carboniferous Extinction 345 Devonian: 30% of animal families, including agnathan and placoderm fishes and many trilobites. Devonian Paleozoic Silurian Ordovician Extinction 500 Ordovician: 50% of animal families, including many trilobites. Cambrian

  20. Effects of Humans on Biodiversity • The scientific consensus is that human activities are decreasing the earth’s biodiversity.

  21. SPECIES EXTINCTION • Species can become extinct: • Locally: A species is no longer found in an area it once inhabited but is still found elsewhere in the world. • Ecologically: Occurs when so few members of a species are left they no longer play its ecological role. • Globally (biologically): Species is no longer found on the earth. Some animals have become prematurely extinct because of human activities.

  22. Endangered and Threatened Species: Ecological Smoke Alarms • Endangered species: so few individual survivors that it could soon become extinct. • Rare species: so few individual survivors that it could soon become extinct. • Threatened (Vulnerable) species: still abundant in its natural range but is likely to become endangered in the near future.

  23. Florida manatee Kirkland’s warbler Grizzly bear Knowlton cactus African elephant Swallowtail butterfly Humpback chub Utah prairie dog Siberian tiger Golden lion tamarin

  24. Giant panda Blue whale Whooping crane Northern spotted owl Black-footed ferret Mountain gorilla Florida panther California condor Hawksbill sea turtle Black rhinoceros

  25. SPECIES EXTINCTION • Some species have characteristics that make them vulnerable to ecological and biological extinction. • https://youtu.be/VEMtc1w4z6c Figure 9-4

  26. SPECIES EXTINCTION • Scientists use measurements and models to estimate extinction rates. • The International Union for the Conservation of Nature and Natural Resources (IUCN) publishes an annual Red List, listing the world’s threatened species. • The 2015 Red List contains 16,306 species at risk for extinction. Up from 16,118 last year.

  27. SPECIES EXTINCTION • Percentage of various species types threatened with premature extinction from human activities.

  28. Causes of Endangerment • Conservation biologists summarize the most important causes of premature extinction as “HIPPCO”: • Habitat destruction, degradation, and fragmentation • Invasive species • Population growth • Pollution – air, water, soil, etc • Climate Change • Overharvest over-hunting, commercial harvest (sold for profit) • Habitat Loss- people moving in (the number one reason for endangerment!)

  29. Habitat Destruction • Habitat loss—due to destruction, fragmentation or degradation of habitat—is the primary threat to the survival of wildlife. • May be natural or unnatural, and may be caused by habitat fragmentation, geological processes, climate change, or human activities such as the introduction of invasive species or ecosystem nutrient depletion. • The current rate of deforestation is 160,000 square kilometers per year, which equates to a loss of approximately 1 % of original forest habitat each year. Other forest ecosystems have suffered as much or more destruction as tropical rainforests.

  30. Natural Capital Forests Ecological Services Economic Services Support energy flow and chemical cycling Reduce soil erosion Absorb and release water Purify water and air Influence local and regional climate Store atmospheric carbon Provide numerous wildlife habitats Fuelwood Lumber Pulp to make paper Mining Livestock grazing Recreation Jobs Fig. 10-4, p. 220

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