Other Sites of Interest
By Geography
![Clickable Map of the U.S.](https://webarchive.library.unt.edu/eot2008/20080916164209im_/http://www.npwrc.usgs.gov/images/resout.gif)
Contents
Select from the map above or use the text links below.- International
- Resources pertaining to areas around the world.
- United States
- Resources pertaining to all of the United States.
- Great Plains
- Resources pertaining to the Great Plains region.
- Great Plains
- Colorado -- Iowa -- Kansas -- Minnesota -- Missouri -- Montana -- North Dakota -- Nebraska -- Oklahoma -- New Mexico -- South Dakota -- Texas -- Wyoming
- East of Great Plains
- Alabama -- Arkansas -- Connecticut -- Delaware -- Florida -- Georgia -- Illinois -- Indiana -- Kentucky -- Louisiana -- Massachusetts -- Maryland -- Maine -- Michigan -- Mississippi -- North Carolina -- New Hampshire -- New Jersey -- New York -- Ohio -- Pennsylvania -- Rhode Island -- South Carolina -- Tennessee -- Virginia -- Vermont -- Wisconsin -- West Virginia
- West of Great Plains
- Alaska -- Arizona -- California -- Hawaii -- Idaho -- Nevada -- Oregon -- Utah -- Washington
Note: Northern Prairie does not guarantee the content or integrity of the links below as they are provided and maintained by outside parties.
International
- Alberta Butterflies
- Includes tips for beginners, results of butterfly counts, and other information about butterflies in Alberta.
- Alberta Prairie Conservation Forum
- A large voluntary coalition of stakeholder groups whose members are interested in the conservation of native prairie and parkland environments in Alberta, Canada.
- Alexanor
- Contains a species list, literature sources, statistics, databases, mapping, and photos of butterflies in the SW Ukraine territory.
- Amphibs
- The home page of the North American Amphibian Monitoring Project, this page has information on amphibian monitoring projects in progress across the United States and Canada, and information on how you can join the project as a volunteer.
- Animal Diversity Web
- Species accounts, photos, and some sound and video clips for 1600 species of mammals, birds, amphibians, reptiles, sharks, bony fishes, mollusks, arthropods, and echinoderms from throughout the world.
- Bat Conservation International, Inc.
- This site is designed to help readers explore the world of bats through articles, photos, and bat trivia.
- Bird Links to the World
- Birding on the Web
- Bryology at the Missouri Botanical Garden
- The Missouri Botanical Garden provides a unique environment for study and training in bryology. Research activities currently include programs in North, Central and South America, Africa, and Southeast Asia on mosses and hepatics.
- Butterflies and Moths of Southern Vancouver Island
- A descriptive guide to the butterflies and moths of Vancouver Island, British Columbia, Canada.
- Butterflies of Northern Mexico and Sonora
- Photos of butterflies from Sonora state, Mexico.
- Butterflies on the Wings of Freedom
- General information about butterflies, including a kids section, photos taken with an electron microscope and a high speed shooting of a hummingbird hawkmoth's flight.
- Butterfly Species Richness Patterns in Canada: Energy, Heterogeneity, and the Potential Consequences of Climate Change
- Reviews the effects of climate change on pollinators and provides a first analysis of the biodiversity patterns for the butterflies of Canada, a complete pollinator taxon.
- Catalog of Museum Collections
- A growing resource of online data bases of museum collections and related resources.
- Catocala
- Pictures and information about the underwing moths of Canada and the United States.
- Cats and Wildlife: Issues From Around the World
- Chebucto Community Information on Stoneflies
- Provides general information on stoneflies as well as their life history, habitat and ecological preference, feeding, and resources.
- Checklist of Online Vegetation and Plant Distribution Maps
- You'll find maps of the world's rainforest, California's redwoods, protected forests in Bangladesh, and much more on this page of hyperlinks to vegetation maps.
- Climate Change and Its Impact on Biodiversity
- Bibliography of peer-reviewed and gray literature focusing on climate change and its impacts on flora and fauna species and critical supporting ecosystems.
- Common Names of Odonata of North America
- This source provides common names for species of dragonflies and damselflies that are found in North America
- Distribution Summary of North American Anisoptera
- A list of North American dragonfly species and the states or provinces in which they have been recorded.
- DUCKDATA
- A Bibliographic Data Base for North American Waterfowl and Their Wetland Habitats
- Embl Reptile Database
- An online information resource on reptile taxonomy with a focus on the species level.
- Electronic Resources on Ornithology
- E-mail Directory of Odonatists
- Ephemeroptera Galactica: Mayflies at FAMU
- Ephemeroptera information for scientists and aquatic biologists for mayflies around the world.
- Entomology Collection
- A searchable database of the E. H. Strickland Entomological Museum of the Department of Biological Sciences at the University of Alberta.
- Entomology Index of Internet Resources
- A searchable database of insect-related resources on the Internet. Resouces include WWW sites, gopher and FTP, Usenet news, electronic mailing lists, etc.
- The Few, The Proud, The Marine Insects
- Explore some of the most popular hypotheses as to why there are so few insect species that can survive exposure to seawater.
- HUDSON BAY PROJECT: Ecosystem Studies and Conservation of Coastal Arctic Tundra
- Images of Odonates
- Provides photographs of Odonates of both Canada and the United States
- The Insect Family Tree
- A Key to the Principle Orders and Families of Insects.
- International Crane Foundation
- World center for the conservation of cranes.
- International Goose Research Group
- Established to facilitate the exchange of information concerning goose research and managers, both amongst those actively working with geese, and between the scientific and management community and the general public.
- The International Lepidoptera Survey: The Taxonomic Report
- A non-profit organization devoted to the discovery, determination, and documentation, of new butterflies and moths around the world.
- International Organization for Plant Information (IOPI)
- Manages a series of cooperative international projects that aim to create databases of plant taxonomic information.
- International Wolf Center
- This site's mission is to support the survival of the wolf around the world by teaching about its life, its association with other species and its dynamic relationships to humans.
- Internet Directory for Botany
- Journey North
- Geared towards students, a learning tool that uses the Internet in a global study of wildlife migration and seasonal change.
- Land Use History of North America
- A National Biological Service led effort to provide a historical perspective on environmental conditions prior to European settlement and subsequent changes in the North American landscape.
- The Lepidopterists' Society
- Includes links to Internet Resources For Lepidopterists (And All Other Entomologists).
- Living Landscapes: Pend-d'Oreille Butterfly Survey
- This study opens the door on the "biodiversity central" of the British Columbia butterfly world.
- Mayfly Central
- From the Department of Entomology at Purdue University this site provides species lists for both North America and Central America.
- The Mushroom Genus Laccaria in North America
- Includes a tentative key to the world taxa of Laccaria.
- The National Soil DataBase (NSDB)
- A set of computer readable files which contain soil, landscape, and climatic data for all of Canada.
- The Nature Conservancy
- Neartica: The Natural World of North America
- A collection of links and other information pertaining to the natural world of North America
- New World Odonata
- Listing of species of Odonata by family.
- Noctuid Search
- An interactive key to identify the Noctuidae of North America.
- North American Bird Sounds
- Sounds of North American birds including calls, songs, wing sounds, and bill rattles.
- North American Butterfly Association (NABA)
- Contains daily sightings from around the continent, a downloadable checklist of North American butterflies, free butterfly gardening brochures and activities of the many NABA chapters, including butterfly photographs and conservation initiatives.
- North American Stonefly List
- List of 618 species of stoneflies and where they reside by state and province.
- Odonata Central
- Searchable pages that provide photographs and distribution of Odonates primarily in North America.
- Odonata Information Link
- Provides information on Odonata from around the world and Odonata upcoming events.
- Odonata Links on the World Wide Web
- Odonata Photo Archive
- Some photographs of Odonata species on the web.
- Partners In Flight
- Photographs from Nature - Butterfly Gallery
- High quality images of many species of butterflies found in Canada.
- Phylogenetic Systematics of Odonata
- This site provides clades, phylogenetic systematics, and fossils of Odonata.
- Spider Conservation
- Dedicated to raising awareness and exchanging information to protect spider diversity.
- Stoneflies Found in the Streams of the Kuril Islands and Adjacent Regions
- Listing of species in 7 families of stoneflies in the Kuril Islands and surrounding regions.
- Strategies for Bird Conservation: The Partners in Flight Planning Process
- This web site is the electronic proceedings of the 1995 Partners in Flight (PIF) International Workshop, "Partners in Flight Conservation Plan: Building Consensus for Action."
- The Virtual Library of Ecology & Biodiversity
- An organized and searchable database on conservation issues.
- Wildflowers
- Searchable by state, this site can guide you to both internet and printed resources, and to places to view wildflowers in "real life".
- Wild Wing: Heading North
- Tracks radiocollared snow geese as they migrate north.
- The World-Wide Web Virtual Library: Entomology (Biosciences)
- Includes areas on upcoming events in entomology, job opportunities, entomology on the internet, publications, and pictures.
United States
- ActionBioscience
- A non-commercial, ad-free, educational site promoting literacy in the biosciences by featuring peer-reviewed articles and class lessons in the areas of biodiversity, environment, genomics, biotechnology, evolution, new frontiers, and bioscience education.
- American Bird Conservancy
- Dedicated to the conservation of wild birds and their habitats in the Americas.
- Benthic Macroinvertebrates: Order Ephemeroptera
- Includes an identification key to the orders of benthic insects and also includes some nymph drawings.
- BRD - Great Lakes Science Center
- BRD - Leetown Science Center
- BRD - Midcontinent Ecological Science Center
- BRD - National Wetlands Research Center
- BRD - National Wildlife Health Center
- BRD - The North American Breeding Bird Survey
- A variety of data and information on birds, including population trends, analysis and interpretation, annual indices, abundance and trend maps, and songs and pictures of common North American birds.
- BRD - Patuxent Wildlife Research Center
- BRD - Upper Midwest Environmental Sciences Center
- BRD - Wisconsin Cooperative Park Studies Unit
- Birds at Selected National Parks
- Dave Powell's Butterfly Site
- Dragonfly (Odonata) Biodiversity
- Provides links to lists, keys, photos, and other material of interest for dragonflies and other Odonata.
- Farm Service Agency Online
- Conservation Reserve Information page.
- FWS - National Wetland Inventory
- National Audubon Society Online Field Guides
- This site offers online searchable field guides to over 4,800 plant and animal species. Derived from 35 different Audubon Society Field Guides, Regional Guides, and Nature Guides, the database is keyword-searchable by group (mammals, amphibians, fishes, trees, etc.) or browseable within subheadings for each group.
- The North American Bird Conservation Initiative (NABCI): Integrated Bird Conservation in the United States
- This site is dedicated to promoting and advancing integrated bird conservation in the United States.
- Partners In Flight
- A conservation initiative launched in 1990 in response to growing concerns about declines in the populations of many land bird species.
- Plant Conservation Alliance
- Devoted to solving the problems of native plant extinction and native habitat restoration, ensuring the preservation of our ecosystem.
- Prairies Forever
- Dedicated to promoting the ecological and cultural significance of the American prairie through education, outreach, and public engagement.
- United States Department of Agriculture
- United States Department of Agriculture Natural Resources Conservation Service
- Information, descriptions, and pictures of thousands of plants. The PLANTS Database provides a single source of standardized information about plants. PLANTS also provides standardized plant names, symbols and other plant attribute information.
- USDA - Agricultural Research Service
- USDA - Forest Service
- USDA - National Agricultural Statistics Service
- USDA - Natural Resources Conservation Service
- United States Department of the Interior
- USDI - Bureau of Land Management
- USDI - Bureau of Reclamation Home Page
- USDI - Fish and Wildlife Service Home Page
- USDI - Geological Survey
- USDI - National Park Service Home Page
- USGS - Geospatial Technology Program
- Web Images of North American Moth Species
- Provides images for many moth species found throughout North America
- Wing Photos
- A University of Puget Sound website that provides an extensive collection of bird wing photos.
Great Plains
- Great Plains Nature Center
- Provides opportunities to the public to learn about natural resources, especially the wildlife and plant species, of the Great Plains Region.
- Nematodes of the Northern Great Plains
- Based on a 1968 survey of plant parasitic nematodes, this site includes descriptions, photographs, scanning electron micrographs, molecular markers, and distributions.
- U.S. Environmental Protection Agency
- Condition, Values, And Loss Of Natural Functions Of Prairie Wetlands Of The North-Central United States
- Conceptual Process Model for Basin-type Wetlands of the Prairie Pothole Region
Alabama
Alaska
- Alaska Department of Fish and Game
- Mainly information on the Department and its programs. Includes a wildlife photo gallery, drawings of fish, and technical papers dealing with subsistence.
- Odonata of Alaska
- Listing of Odonata species and localities of sightings or collection in the state of Alaska.
Arizona
- Arizona Game and Fish Department
- Butterflies of Southeastern Arizona
- The Large Moths of Southeastern Arizona
Arkansas
California
- California Department of Fish and Game
- Information on the Department and its programs. Includes some photos and information on mountain lion/human interactions.
- California Dragonfies and Damselflies
- Listing of dragonflies and damselflies of the California region.
- Cats and Wildlife: Issues From Around the World
- Spiders of San Diego County
- This site contains a checklist for spiders found in San Diego County, California.
Colorado
- Diatom Checklist: Central United States
- Register of Taxa and Synonyms for Diatoms recently reported from the Central United States.
Connecticut
- Connecticut Amphibians
- This site contains a list of all the amphibians in Connecticut, including photos and life histories of frogs and salamanders.
- Moths in a Connecticut Yard
- A photo record of moth occurrences in an observer's yard in Connecticut.
- Tiger Beetles of Connecticut
Delaware
Florida
- Florida Game and Fresh Water Fish Commission
- Information on hunting, fishing, wildlife viewing, and agency publications. Also included are resources for educators and a directory of agency personnel and offices.
- Florida Museum of Natural History -- Herpetology
- Links to information on herps in Florida.
- Tall Timbers Research Station
- Tall Timbers works to accomplish a sustainable balance between people and natural systems through long-term studies.
Georgia
- The Dragonflies and Damselflies (Odonata) of Georgia
- International Odonata Research Institute list of Georgia species displaying individual counties along with the source of the records.
- Georgia Lepidoptera
- Moths and Butterflies of Georgia and the Southeastern United States.
Hawaii
Idaho
- Endangered Species Information Network
- Information on federally and state listed endangered, threatened and sensitive species as well as other species of conservation concern in the Pacific Northwest.
- Idaho Conservation Data Center
- Site-specific information on rare, threatened, and endangered plants and animals, exemplary plant communities, and natural areas.
- Idaho Department of Fish and Game
- General information, education, fisheries, natural resources, wildlife enforcement, and news/media.
- Idaho Fish and Wildlife Foundation
- A non-profit organization formed to facilitate the organization and funding of selected fish, wildlife, education, habitat and study projects throughout Idaho.
- Odonata of Idaho
- Provides a species list of Odonata along with the localities of sightings or collection in the state of Idaho.
- Pacific Biodiversity Institute (PBI)
- A scientific research organization with activities focused on the conservation of biodiversity and maintenance of ecological integrity in the Pacific Northwest region.
Illinois
- Database of Illinois Odonata II
- Checklist of Odonata species occurences by county in Illinois.
- Illinois Checklist of Plecoptera
- Listing of the stonefly species that inhabit Illinois.
- Illinois Department of Natural Resources
- State parks, licenses and permits, DNR publications, critical trends assessment, minerals and energy, laws and legislation, and educational material for teachers and kids.
- Midewin National Tallgrass Prairie
- Information on the restoration and management of Midewin National Tallgrass Prairie.
- The Parasitic Plant Connection
- The Tallgrass Prairie in Illinois
Indiana
- Indiana Audubon Society
- Includes information about the Society, including activities, membership, history, publications, as well as rare bird sightings in Indiana.
- Indiana Department of Natural Resources
- Information on the Department and its programs, including state parks and Indiana natural heritage data.
Iowa
- The Dragonflies & Damselflies of Iowa
- A comprehensive accounting of the odonates in Iowa with county maps included.
- Friends of the Prairie Learning Center
- Includes information on the Prairie Learning Center at the Neal Smith National Wildlife Refuge.
- Iowa Department of Natural Resources
- Iowa Ornithologists' Union
- Iowa Prairie Network
- Information to learn about, teach about, enjoy and protect Iowa's prairie heritage.
Kansas
- Diatom Checklist: Central United States
- Register of Taxa and Synonyms for Diatoms recently reported from the Central United States.
- Konza Prairie Long Term Ecological Research (LTER) Program
- Information about the Konza Prairie Long Term Ecological Research (LTER) Program and other research at the Konza Prairie Biological Station.
- Odonata: Dragonflies and Damselflies
- Provides links to Odonata of Kansas, Oklahoma, and Texas and a list of other sites relating to Odonata.
- The Prairie Falcon
- Devoted to information on birds and birding in Kansas and the northern Flint Hills.
- Unionid Mussel Checklist: Kansas
- Register of Taxa, Synonyms, and Assumed Misidentifications for the Freshwater Mussels of Kansas.
Kentucky
- The Kentucky Fish and Wildlife Information System
- An inter-and intra-agency resource, which contributes to the understanding of Kentucky's wildlife, and its relationship with the environment.
Louisiana
Maine
- Maine Department of Conservation
- Maine Damselfly and Dragonfly Survey
- Contains checklists and distributions as well as flight periods for Odonata in Maine.
Maryland
Massachusetts
- Massachusetts Audubon Society -- Conserving Grassland Birds
- Presents information concerning the conservation of birds on small, large, and agricultural grassland areas.
- Massachusetts Department of Fisheries, Wildlife, and Enviromental Law Enforcement
- Ode News
- Includes checklists of Odonates of Cape Cod and Massachusetts, and a bibliography of New England Odonatology.
Michigan
- Michigan Department of Natural Resources
- Michigan Lepidoptera Survey
- This page is dedicated to documenting the identity, distribution, and biology of Michigan's diverse lepidopteran fauna.
- Michigan Odonata Survey
- Contains checklists, databases, and other resources for Odonata in Michigan.
Minnesota
- Minnesota Department of Natural Resources
- Minnesota Ornithologists' Union
- A fantastic home page on birds found in Minnesota, including distribution maps, publications about Minnesota birds, species at risk, rare bird sightings, and much more.
- On the Prairie
- Includes information geared toward students, including an interactive game to restore a prairie.
Mississippi
Missouri
- Diatom Checklist: Central United States
- Register of Taxa and Synonyms for Diatoms recently reported from the Central United States.
- Missouri Department of Conservation
- Missouri Department of Natural Resources
Montana
Nebraska
- Diatom Checklist: Central United States
- Register of Taxa and Synonyms for Diatoms recently reported from the Central United States.
- Nebraska Game and Parks Commission
- Geared towards the public, this is an excellent site featuring a variety of information on the Department, its programs, and natural resources of Nebraska.
- The Tiger Beetles of Nebraska
- Includes a complete list of tiger beetles that occur in Nebraska.
Nevada
New Hampshire
New Jersey
- New Jersey Audubon Society
- Includes information on the New Jersey Audubon Society, as well as details on birds and birding in New Jersey, including education, research conservation, calendar of events, and rare bird sightings.
- New Jersey Natural Heritage Program
- Includes information on rare species and natural communities.
- Odonata of New Jersey
- Annotated list containing geographic information for the Odonata of New Jersey.
New Mexico
- Dragonflies of New Mexico
- Provides a simplifies Odonata list showing distribution by county in New Mexico.
New York
North Carolina
- Department of Entomology at NCSU Information on Stoneflies
- General information about stoneflies including classification, life history and ecology, distribution, physical features, and importance.
- Notes of the Butterflies of North Carolina
- Contains extensive natural history information on all N.C. butterflies, including flight phenograms, and county atlases.
- North Carolina Division of Parks and Recreation
- Information on state parks and heritage program. Species lists of endangered plants and animals are available.
North Dakota
- GEOLOGY IN NORTH DAKOTA: Resources for students, teachers geologists, and the public
- Locations, explanatory texts, and jpeg photos of geologic features in North Dakota.
- Moths of North Dakota
- An online identification guide, photo gallery, and glossary for moths located in North Dakota.
- North Dakota Game and Fish Department
- North Dakota Natural Heritage Program
Ohio
- Ohio Department of Natural Resources
- Ohio Odonata Society
- Read research news and view species maps and images for Odonata in Ohio.
Oklahoma
- Diatom Checklist: Central United States
- Register of Taxa and Synonyms for Diatoms recently reported from the Central United States.
- Noble Foundation Plant Image Gallery
- Contains images of over 600 vascular plants native primarily to the Oklahoma-Texas region.
- Odonata: Dragonflies and Damselflies
- Provides links to Odonata of Kansas, Oklahoma, and Texas and a list of other sites relating to Odonata.
- Oklahoma Conservation Commission
- Oklahoma Wildflowers
Oregon
- Endangered Species Information Network
- Information on federally and state listed endangered, threatened and sensitive species as well as other species of conservation concern in the Pacific Northwest.
- Oregon Dragonfly and Damselfly Survey
- Checklists, county records, migration notes, and photo gallery of Odonata in the state of Oregon.
- Oregon Department of Fish and Wildlife
- Includes recreation and education, regulation information, news and publications, agency organization, available databases, and research and reports.
- Pacific Biodiversity Institute (PBI)
- A scientific research organization with activities focused on the conservation of biodiversity and maintenance of ecological integrity in the Pacific Northwest region.
Pennsylvania
Rhode Island
South Carolina
- South Carolina Department of Natural Resources
- General information about the Department. Includes rules and regulations and some data related to groundwater levels, lake levels, and streamflows.
South Dakota
- South Dakota Birds
- Devoted to birds and birding in the State of South Dakota.
- South Dakota Department of Game, Fish and Parks
Tennessee
Texas
- Damselflies of Texas
- Presents a small sampling of both scans and photographs of damselflies found in Texas.
- Digital Dragonflies
- Contains high quality images of selected specimens of dragonflies from central Texas.
- Dragonflies and Damselflies of Houston, Texas, and Vicinity
- Lists species that have been found to occur in Houston, Texas and the surrounding counties.
- Noble Foundation Plant Image Gallery
- Contains images of over 600 vascular plants native primarily to the Oklahoma-Texas region.
- Odonata: Dragonflies and Damselflies
- Provides links to Odonata of Kansas, Oklahoma, and Texas and a list of other sites relating to Odonata.
- Texas Ornithological Society
- Texas Parks and Wildlife
- Contains information on hunting, fishing, and boating. Also has information on endangered species and wildlife species accounts. Some useful educational material for kids.
Utah
- Surweb Learning Resources
-
The mission of the SURWEB project is to develop Internet WEB pages from
resources of Utah, and foster the concept that education is the utilization of
information from worldwide resources. This resource contains a wide variety of information including media slide shows and various desciptions and classifications.
Common Insects of Utah
Insects of Utah
Mammal Skulls of Utah
Reptiles and Amphibians in Bryce Canyon NP
Trees of Utah
Wildflowers of Southwest Utah - Utah Department of Natural Resources
- The Utah Lepidopterists' Society
- The ULS is a non-profit educational and scientific organization dedicated to the study and enjoyment of all aspects of Lepidoptera especially Lepidoptera of Utah.
Vermont
- State of Vermont Agency of Natural Resources
- University of Vermont Extension
- Discussion of the importance, description, and life history of stoneflies.
Virginia
- Virginia Department of Conservation and Recreation
- Home page of the Virginia Natural Heritage Program featuring information on natural areas and other resources, including rare plants and animals.
- Virginia Department of Game and Inland Fisheries
- Provides information about wildlife, fisheries and boating in the Commonwealth of Virginia.
Washington
- Endangered Species Information Network
- Information on federally and state listed endangered, threatened and sensitive species as well as other species of conservation concern in the Pacific Northwest.
- Pacific Biodiversity Institute (PBI)
- A scientific research organization with activities focused on the conservation of biodiversity and maintenance of ecological integrity in the Pacific Northwest region.
- Rainer Audubon Society
- Washington Breeding Bird Atlas
- Washington Department of Fish and Wildlife
- General information about the Department and its programs. Includes list of priority habitats and species.
- Washington Dragonfly Survey
- Contains a listing of species, field key, photo gallery, and range maps for Odonata in the state of Washington.
- Washington Ornithological Society
- Includes information about the Society and checklists of Washington birds, as well as many birding and ecological links.
West Virginia
Wisconsin
- The Hine's Emerald Gallery
- Site dedicated to presenting information about Somatochlora hineana, the only dragonfly on the U.S. Fish and Wildlife Service List of Endangered Species.
- Wisconsin Breeding Bird Atlas
- Provides records, data summaries, species maps and images for the breeding birds of Wisconsin.
- The Wisconsin Herpetology Homepage
- Dedicated to providing information on the amphibians and reptiles of Wisconsin.
- Wisconsin Plant of the Week
- A photographic guide to native and introduced vascular plant species, growing without cultivation in Wisconsin.