Topic: Introduced Species & Endangered Species Notes Introduced Species & Endangered Species What is bioinvasion? The introduction of species, by direct or indirect human actions, to areas where they did not previously exist. 1 2 Non-native species: Also referred Species introduced to areas beyond their historic natural range. to as: alien exotic foreign introduced non-indigenous species 3 Topics, Concepts, Review Why are They are aggressive & some spread over large areas, called disrupting natural invasive ecosystems and species? interfering with human activities. They are costly ($123 billion/yr in U.S.) They can bring new diseases 4 What are the worst threats to endangered species & biodiversity? 1. Habitat destruction by human activities 2. Invasive species 5 European starlings imported from England in 1890: Droppings contain a fungus that causes histoplasmosis (human respiratory disease). Drive out natives from nesting sites & compete with them for food. Omnivores eat insects & farm crops. 6
Water hyacinth bordering Gulf Coast: Aquatic plant native to South America. Brought over because of its beauty & easy care. It escaped cultivation & now is a weed. Turned open waterways into wetlands & then choked the life out of them. 7 South American weevil had to be imported to feed on the hyacinth. So another exotic species had be brought over to be used as a biological control agent. 8 Other nonnatives who have caused havoc in the U.S.: Kudzu Purple loosestrife Zebra mussels European elm bark beetles Gypsy moths Kudzu vine Africanized hybrid bees Mediterranean fruit flies European wild boar Argentina fire ant Sea lamprey 9 10 11 12
When nonindigenous species immigrate to another country: They leave their natural enemies behind such as predators, parasites, and disease. Without these limiting factors, the population can reach epidemic numbers. 13 endangered species threatened species extinct: An organism whose chances of survival & reproduction are in immediate jeopardy. An organism that is likely to become endangered. Disappeared from the Earth. 14 Passenger pigeon Global Great auk Dodo Golden toad Aepyornis (Madagascar) occurs when the population cannot adapt to changing environmental conditions. 15 adaptation inherited trait that increases survival Endangered Species Act of 1973: Requires the U.S. Dept. of the Interior to identify & protect species that are in danger of extinction. Prohibits killing, harming, or taking endangered or threatened species. Includes destruction or taking of their habitat. Goal is to restore populations to self-sustaining. 16 Shows a few of the roughly 1,300 species listed as endangered and protected under the US Endangered Species Act. Grizzly bear Kirkland s warbler Knowlton cactus Florida manatee Utah prairie Swallowta dog il butterfly Humpback Golden lion chub tamarin Giant panda Blackfooted ferret Whooping crane Northern spotted owl African elephant Siberian tiger Blue whale Characteristics of species that are prone to ecological & biological extinction. Mountain gorilla Florida panther California condor Hawksbill sea turtle Black 17 rhinocero s 18
Plants & animals have disappeared from our planet before humans existed: Before modern times, there were at least 5 major mass extinctions that took place over the past 500 million years. Ordovician Period Devonian Period Permian Period Triassic Period Cretaceous Period 19 Era Mesozoic Cenozoic Paleozoic Period Quaternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian Millions of years ago Today 65 180 250 345 500 Bar width represents relative number of living species Species and families experiencing mass extinction Current extinction crisis caused by human activities. Many species are expected to become extinct within the next 50 100 years. Cretaceous: up to 80% of ruling reptiles (dinosaurs); many marine species including many foraminiferans and mollusks. Triassic: 35% of animal families, including many reptiles and marine mollusks. Permian: 90% of animal families, including over 95% of marine species; many trees, amphibians, most bryozoans and brachiopods, all trilobites. Devonian: 30% of animal families, including agnathan and placoderm fishes and many trilobites. Ordovician: 50% of animal families, including many trilobites. 20 Human activities are causing extinctions at a much higher rate than in the past. India, Africa, Asia, South America: Many scientists say that we are now in the midst of a 6 th mass extinction, caused primarily by human activities. Increasing human population growth is taking away space from 21 other species. poaching: The taking of a species by any illegal means; illegal hunting. habitat fragmentation: When breeding is limited to a small group, young are born w/birth defects & mutations, reducing their survival rate. 22 Kirtland s warbler: One of the world s rarest birds. Population threatened by changing habitat & competition from the cowbird. Nests in only a few Michigan counties beneath jack pine trees that grow 23 in sandy soil. It makes a hole in sandy soil which protects the nest from flooding, & as tree grows, it creates shade. Fires help maintain the warbler s habitat pine cones only open when exposed to intense heat. 24
Topics, Concepts, Review DDT: Dichloro-diphenyltrichloroethane; the first chlorinated hydrocarbon used as an insecticide (kills bugs). Bioaccumulation with predators high up food webs Adversely affects reproduction of some birds (ex: brown pelican & California condor) 25 Plants as chemical factories: Some chemical compounds are so complex that they can t be economically synthesized in a lab. More than ¼ of all prescription drugs contain compounds derived from plants. Rosy periwinkle from Madagascar is the source of vincristine, used to treat childhood leukemia & vinblastine, used in the treatment of Hodgkin s disease. 26 85% of our food comes from only 20 species! None of our major food crops are native to U.S. (rice, wheat, corn, potatoes, beans, soybeans, cane, beets, bananas, & coconuts) Monocultures very low genetic variety not resistant to pests, disease, etc. This is why we have to use so much insecticides & herbicides! 27 Benefits of seeds from plants growing in the wild: Produce a genetic variety that will: improve plant yield higher productivity more biomass. make them more resistant to drought, disease, &/or insect damage. 28 Why is it important to protect ALL species? The death of a species is the loss of genetic material. We might need one of these species in the future. Species not yet discovered may be vital to the production of food, clothing, medicines, 29 etc. Species may be vital to the existence of certain ecosystems that sustain the planet. biodiversity: Improves the stability of ecosystems, & the loss of species reduces the ecosystem's diversity. 30
keystone species: Organisms that play an important role in stabilizing an ecosystem; keep ecosystem in balance. Removal can cause a chain reaction disrupting many other species. 31 Keystone Species: Major Players Keystone species help determine the types and numbers of other species in a community, thereby helping to sustain it. an ecosystem may experience a dramatic 32 shift if a keystone species is removed. Examples of keystone species that maintain structure of a community: 1) Elephants 2) Starfish 3) Sea otters Which 4) Dung beetles 5) Jaguars 6) Acorn banksia tree 7) Grizzly bear 8) Prairie dogs 9) Beaver animal is an apex predator? Jaguar & Grizzly bear 33 Don t Forget to Computer Lab! Find out why each individual species (ones listed in your notes) is a keystone species for their community. 34