Projected Status of Biodiversity 1998–2018 Critical and endangeredThreatenedStable or intact ANTARCTICA NORTH AMERICA EUROPE AFRICA ASIA SOUTH AMERICA AUSTRALIA Pacific Ocean Antarctic Circle Pacific Ocean Tropic of Cancer Tropic of Capricorn Indian Ocean Atlantic Ocean 150°90°60°E0°30°W90°120°150°0° 60° 30°N 30°S 60° Arctic Circle
What are the relationships among ecosystem stability, diversity, succession and habitat ?
How does diversity change during succession? How does habitat diversity influence species diversity and genetic diversity? How does ecosystem complexity, with its variety of nutrient and energy pathways, provide stability? How do human activities (agriculture, mining, logging, etc.) modify succession? What are the potential positive and negative results of human activities that simplify ecosystems? (monocrop agriculture)
Why Should We Care About Biodiversity? Instrumental value: usefulness to us. Instrumental value: usefulness to us. Intrinsic value: because they exist, Regardless of whether they are useful to us or not. Intrinsic value: because they exist, Regardless of whether they are useful to us or not.
Goods Food, fuel, ecosystems, species, fiber, lumber, paper, … 90% of today’s food crops 40% of all medicines (85% of antibiotics) Foxglove Digitalis purpurea, Europe Digitalis for heart failure Pacific yew Taxus brevifolia, Pacific Northwest Ovarian cancer
Ecological Services: Flow of materials, energy, and information in the biosphere Photosynthesis Pollination Soil formation and maintenance Nutrient recycling Moderation of weather extremes Purification of air and water
Information: Genetic information: adaptation and evolution Genetic information for genetic engineering Educational and scientific information Option: People would be willing to pay in advance to preserve the option of directly using a resource such as a tree, an elephant, a forest or a clean lake.
Recreation: Existence Aesthetic Protect natural capital for future generations Nonutilitarian: Hunting, fishing, swimming, scuba diving, water skiing,.... Eco-tourism
Evolution are the changes in the gene pool of a population over time. Natural selection process by which individuals that are better suited to their environment survive and reproduce most successfully. Adaptation is an inherited characteristic that increases an organism’s chance of survival.
Isabela Darwin Wolf Pinta Marchena Genovesa Fernandia Santiago Bartolomé Råbida Pin zon Seymour Baltra Santa Cruz Santa Fe Tortuga Española San Cristobal Floreana EQUATOR Galåpagos Islands
FOUNDER SPECIES insect and nectar eatersfruit and seed eaters KAUAI AKIALAOA AMAKIHI IIWI APAPANE KONA FINCH extinct LAYSAN FINCH AKIAPOLAAU MAUI PARROTBILL
Based on his observations, Darwin proposed that EVOLUTION occurs by NATURAL SELECTION.
Darwin’s Postulates Variation within populations. Overproduction of offspring. Struggle for existence. Unequal survival and reproduction rates. http://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html
Population of organisms Limited resources leads to a struggle for survival between offspring. Overproduction of offspring Survivors reproduce more successfully. Mutations & Sexual reproduction produces variations among offspring. Population changes over time.
Fig. 27.19b, p. 471 PLACENTAL MAMMALS EVOLVE; ADAPTIVE RADIATIONS BEGIN Isolation of the early monotremes, marsupials on this land mass Between 100 and 85 million years ago, during the Cretaceous
PLACENTAL MAMMALS Walruses Bat Manatee Arctic Fox
Beaver NORTH AMERICA Muskrat Capybara SOUTH AMERICA Coypu Beaver Muskrat Beaver and Muskrat Coypu Capybara Coypu and Capybara
Fig. 27.19c, p. 471 North America ADAPTIVE RADIATIONS OF MORE EVOLVED PLACENTAL MAMMALS South America Antarctica Africa Eurasia Continued isolation of early monotremes and marsupials Extinctions of mammals About 20 million years ago, during the Miocene
Fig. 20.10, p. 319 RACCOONRED PANDAGIANT PANDA DIVERGENCE approximately 40 million years ago DIVERGENCE 15-20 million years ago SPECTACLED BEAR SLOTH BEAR SUN BEAR BLACK BEAR POLAR BEAR BROWN BEAR
A group of potentially or actually interbreeding populations, with a common gene pool, which are reproductively isolated from other groups
The problem with the species definition The species concept is a human construct used to make sense of the natural world. While extraordinarily helpful in understanding life, it fails to capture the full complex reality of continually evolving populations of organisms.
Sibling Species Species that can’t interbreed, but have no significant differences in appearance.
Very different appearance that can interbreed?!
The "Toast of Botswana", -- a hybrid of a female goat to a male sheep; A "cama" -- a hybrid of camel and llama; A "yakalo" - a hybrid of buffalo or bison and yak; A "cattalo" (or "beefalo") -- a cross of a bison with a domestic cattle; A "coywolf" -- a hybrid of coyote and wolf; A "wholphin" -- a hybrid of a bottlenose dolphin mother and a false killer whale father. Same situation like with the "pumapard" (parents belong to different genera). Some intraspecies hybrids (both genders fertile): A "wig" -- a cross of a wild and a domestic pig; An unnamed cross of a Siberian and a Manchurian tiger.
Non-human causes of extinction: Volcanic events Ocean temperature change Sea level changes Meteorites Glaciations Global climate change Competition/predation
Human causes of extinction/loss of biodiversity - HIPPO Habitat destruction and fragmentation Introduced species Pollution Population Over consumption
Rates of Extinction: = number of species becoming extinct per unit time. Rates of extinction are very difficult to estimate, because we don't even know within an order of magnitude how many species there are. Fossil records can reveal the average "lifetimes" of species, or how long different classes of plants and animals generally exist on the earth before going extinct.
From this information, scientists can determine a "background" rate of extinction, or the natural rate of extinction without human intervention. Because of human intervention the Earth's species are dying out at an alarming rate, up to 1,000 times faster than their natural rate of extinction.
By carefully examining fossil records and ecosystem destruction, some scientists estimate that as many as 137 species disappear from the Earth EACH DAY, which adds up to an astounding 50,000 species disappearing every year.
Mammals average species lifespan 1 million years. With ~ 5,000 mammalian species the background extinction rate = 1 every 200 years. In the past 400 years, though, 89 extinctions have been recorded, almost 45 times the natural rate. Over 50 of those extinctions have occurred in the past century, Rate = 100 times the background rate!!
Middle Cambrian age (about 540 million years ago) The locality is special because of the soft-bodied preservation of a wide diversity of fossil invertebrate animals. Period of great speciation.
Characteristics of vulnerable species Small population size - island species. Small population size - species with limited habitats. Extremely specialized species. Species with low reproductive potential. Species that require large territories. Species with limited dispersal ability.
Vulnerable species - continued Migratory species. Species that are economically valuable or hunted for sport Predators. Species that are vulnerable to pollution. Species that are incompatible with civilization.
Rainforest Tropical rainforests contain at least half of the Earth's species. Most species have evolved to inhabit very specialized niches in their environment. When humans disrupt that environment, many species cannot survive. Because species depend on each other in a complicated web of relationships, changing just one part of that web harms the entire ecosystem. This breakdown of rainforest ecosystems will likely lead to the disappearance of up to 10% of the world's species within the next 25 years.
Rainforest continued The human species depends on the rainforest's millions of life forms for its own existence - The genetic diversity found within the rainforests provides invaluable additions to the gene pool which help maintain and improve domestic crops. Without a diversity of strains, crops become overly homogenous and vulnerable to mass blight. Many medicines that we regularly use come from rainforest species.