Presentation on theme: "Chapter 21.1 Biodiversity and Conservation. Biodiversity ~2million different species have been identified and named – Biologists theorize that there may."— Presentation transcript:
Chapter 21.1 Biodiversity and Conservation
Biodiversity ~2million different species have been identified and named – Biologists theorize that there may be hundreds of millions of species left to identify – Species are grouped into 5 (sometimes 6) large categories called kingdoms
Kingdom Prokaryota Many biologists split this kingdom into two: the Archaea and the Bacteria (they look similar but have different biochemistry properties) Characteristic features of prokaryotes – Cells with no nucleus – DNA exists as circular chromosome – Smaller circles of DNA called plasmids are often present – No membrane bound organelles – Only 70S ribosomes present – Cell wall consisting of peptidoglycans – Usually exist as single cells or small groups of cells
Kingdom Protoctista Made up of very diverse range of organisms that don’t really fit into other kingdoms (Kind of like the random bin of organisms)
Kingdom protoctista The characteristic features of protoctists: – Eukaryotic – Mostly single celled or exists as groups of similar cells – Some have animal-like cells (no cell wall) and are sometimes known as protozoa – Others have plant-like cells (with cellulose cell walls and chloroplasts) and are sometimes known as algae
Kingdom Fungi Characteristic features of fungi are: – Eukaryotic – Do not have chlorophyll and do not photosynthesize- they feed heterotrophically – Simple body form: may be unicellular or made up of long threads called hyphae (with or without cross walls) large fungi such as mushroom also have a compact mass of cells as part of their life cycle – Reproduce by spores – Cells have cell walls made of chitin (not cellulose) – Never have cilia or flagella
Kingdom Plantae Characteristics of plants are: – Multicellular eukaryotes with cells that are differentiated to form tissues – Some cells have chloroplasts and photosynthesize – Cell walls are always present and made of cellulose – Cells may occasionally have flagella, for example male gametes in mosses
Kingdom Animalia Multicellular eukaryotes with cells that are differentiated to form tissues Do not have chloroplasts and feed heterotrophically Do not have cell walls Cells sometimes have cilia or flagella
Maintaining biodiversity Biodiversity can be defined as the degree of variation of life forms in an ecosystem Usually taken to include diversity at 3 levels: 1.The number & complexity of communities in the ecosystem 2.The number of diff. species in the ecosystem 3.The genetic diversity of all the species in the ecosystem
Maintaining biodiversity Biodiversity is essential to maintain ecological stability The measure and extent of biodiversity can be regarded as a measure of the ‘health’ of an ecosystem – High biodiversity= healthy – Low biodiversity- sick
Maintaining biodiversity As our human population expands and use more and more resources from diff. environments, biodiversity is being threatened Species are being lost @ alarming rate Conservation involves attempting to slow down, stop, or reverse the loss of biodiversity
Maintaining biodiversity The loss of biodiversity also presents an ethical dilemma: We share our planet with a huge range of other organisms and we have no right to make them extinct
Maintaining biodiversity Biodiversity within an ecosystem helps to maintain stability All of the organisms in an ecosystem interact in many different ways, and if one species disappears, it can have ripple effects throughout the entire community
Maintaining biodiversity There are also direct benefits to human to maintain biodiversity – Around 7000 drugs that are prescribed the doctors are derived from plants – Almost 70% of these plants grow in tropical rain forests – There are doubtless many more possible pharmaceuticals that we do not know about, but if we allow tropical rain forests to disappear, then we are losing potentially life saving drugs
Maintaining biodiversity The drugs vincristine and vinblastine (used to treat cancers of white blood cells) are derived from the Madagascan periwinkle. Madagascan periwinkle is endangered in the wild due to slash and burn agriculture – Fortunately, THE plant is being cultivated in many different countries
Maintaining biodiversity Also, we could use wild plant or animal species to introduce new and useful alleles into our crop plants and farmed animals – Ex: species of rice Oryza longistaminata, which grows wild in Mali, is not suitable for cultivation as a crop plants b/c of its low yield and poor taste. However, it is resistance to a large number of strains of bacterial blight. It has successfully been interbred with cultivated rice to give varieties of rice that are resistant to the disease
Do Now 2.25 1.) List the main differences between a prokaryotic cell and a eukaryotic cell. Which kingdoms are prokaryotic? Eukaryotic? 2.) Which kingdoms contain heterotrophic organisms?
Endangered species The International Union for Conservation of Nature (IUCN) annually publishes a Red List of threatened species 2011 list contained 16,119 species Species in the Red List are all under threat of extinction- disappearing forever from the Earth.
Endangered species Mass extinction events in which millions of species become extinct at once have occurred several time throughout Earth’s history, but all have been due to natural events caused by sudden and huge changes in the environment – Ex: asteroid colliding with planet
Endangered species Currently facing likelihood of another mass extinction event due to habitat loss – Ex: draining wetlands, deforestation, slash and burn agriculture, and pollution of air and water – Also, some species are becoming extinct due to over harvesting (hunting, fishing, etc…)
Endangered species High profile animals on the Red List: pandas, tigers rhinos – Ex: World Wide Fund for Nature (WWF) based 2011 Holiday advertisement around its Adopt-A- Tiger campaign Less inclusion of invertebrates, protists
Endangered species 2011 estimates suggest that the global population of all tiger species is about 5000. In India, the pressure on the remaining tiger population is intense due to a rapidly expanding population In China, tiger products are valued as a cure to a variety of illness, so organized poaching is common
SAQ 21.5 Suggest why the Red List contains more vertebrates than invertebrates.
SAQ 21.5 Suggest why the Red List contains more vertebrates than invertebrates. One possibility is that people are much more aware of vertebrates than invertebrates, so we know more about them. They are larger and more visible than invertebrates. Many people find them more interesting than invertebrates.
Endangered species 2011: western black rhino of Africa declared extinct by IUCN – Northern white rhino declared “probably extinct in the wild” – It is thought that the last Javan rhino in Vietnam was killed by poachers in 2010 – Only the African southern white rhino is flourishing, up from only 100 individuals in start of 20 th century
Endangered species Rhino extinctions, despite years of conservation efforts, continue because of: – A lack of political support for conservation – An increasingly high demand for rhino horn – Internationally organized criminal groups targeting rhinos
Endangered species In order to compile its Red List, IUCN must complete a new census of each species Population numbers are estimated using visual sightings, paw marks, bite marks, droppings, and DNA analysis of droppings
Rescuing endangered species Scimitar-horned oryx lives in semi-deserts in northern Africa Has always been hunted for its meat and skin, but hunting grew exponentially starting in 1950s Listed as endangered in 1960s and 70s A few oryx were caught and transported to zoos throughout the world
Rescuing endangered species Captive breeding program began with captured oryx Care was taken to maintain as much genetic diversity in captive population as possible, so oryx from several different zoos were mated using artificial insemination
Rescuing endangered species While captive breeding was taking place, attempts were being made to provide safe habitats for the oryx, so they could be returned to the wild Large reserved set up in Tunisia 1985: 10 oryx released to reserve 2000: population has grown to over 120
Rescuing endangered species While the oryx program has been a success, some animals simple refuse to breed in captivity Often, it is not possible to create suitable habitats for them, so they cannot be returned to the wild – Ex: captive breeding program for Pandas. Since 1963, 300 pandas have been returned to the wild but no panda has been successfully returned to the wild
SAQ 21.6 Suggest why some animals cannot be bred in captivity
SAQ 21.6 Suggest why some animals cannot be bred in captivity They may need particular factors in their environment before their reproductive systems become able to produce sperm or eggs – for example, to have plenty of space, or to have many others of their species around them. These factors affect their physiology and their behaviour. Courtship may be difficult in the conditions in which they live. They may need particular changes in day length or in food supply to trigger hormonal changes associated with reproduction.
Rescuing endangered species When animals in captivity refuse to breed, various techniques as well as artificial insemination can be used: – Eggs can be collected from fertile females and fertilized by in-vitro fertilization – In some species, another female of a closely related species can act as a surrogate – It is sometime possible to split early embryos, essentially cloning them
Rescuing endangered species In many species, sperm, eggs, and embryos can be stored frozen for later use Such banks of frozen gametes and embryos from endangered species are called “frozen zoos”
Protection of endangered species Zoos and botanic garden help lead to public awareness and support for endangered animals and plants Millennium Seed Bank: bank’s ambition is to collected and store seeds from at least 25% of the world’s plants so that if they become extinct in the wild, they can still be grown from seeds
Protection of endangered species 2007: beginning of Svalbard Global Seed Vault. – Storage conditions ideal for long term preservation of seeds – Opened only during winter months – By Jan 2008 vault held over 500,000 different crop varieties To maintain viability of seeds, every 5 years seeds are germinated and new seeds are harvested from resulting plants
Protection of endangered species To maintain genetic diversity, multiple seeds of the same species are stored – Every time a stored seed is germinated, it is cross pollinated to maintain genetic diversity
Protection of endangered species In order to safely store seeds, they must be dehydrated to contain only about 5% water Some seeds, like rubber, coconut palm, and coffee cannot be dried and frozen – These seeds are referred to as recalcitrant seeds – Only ways to keep the genetic diversity of these species are to collect seeds and grow successive generations or to keep them as tissue culture
Protection of endangered species Coconut palm are particularly difficult seeds to bank The seed (coconut) is very large and embryo is too large to freeze successfully Collectors remove the embryos from the seeds, culture them in sterile tubes, and eventually plant them
SAQ 21.7 It has been suggested that seed banks put selection pressure on the seeds that are different from those that plants would experience in the wild. – How might these selection pressures differ? – How might this affect the chances of success in returning the plants to the wild?
SAQ 21.7 a Selection pressures in the natural habitat might include the ability of the adult plants to survive grazing, wide variations in rainfall or competition with other species. In the seed bank, none of these selection pressures would apply. In the seed bank, the greatest selection pressure will become the ability of the seeds to survive the conditions in which they are stored for a long period of time. b It is possible that the plants that grow from the seeds that have been saved will not have characteristics that will allow them to survive the selection pressures they will encounter in their natural habitat. This could reduce the chances of success in returning them to the wild.
Protection of endangered species Most countries now set aside areas where wildlife and the environment can live protected in the wild where human activities are limited – Ex: conservation areas may be set up where there are strict limits on building, grazing farm animals, hunting, or other activities that would adversely affect native species
Protection of endangered species National parks are areas of land that are controlled by the government and are often protected by legislation There are heavy restrictions on human activities in these parks, and tourism brings in money to pay for their maintenance
Protection of endangered species World’s first national park: Yellowstone National Park, set up in 1872 Last remaining nearly intact ecosystem of the northern temperate climatic zone Serves as both a recreation and a conservation zone