Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Biodiversity wikipedia , lookup
Ecological fitting wikipedia , lookup
Theoretical ecology wikipedia , lookup
Island restoration wikipedia , lookup
Biodiversity action plan wikipedia , lookup
Biogeography wikipedia , lookup
Habitat conservation wikipedia , lookup
Natural environment wikipedia , lookup
Latitudinal gradients in species diversity wikipedia , lookup
Lake ecosystem wikipedia , lookup
Biological Dynamics of Forest Fragments Project wikipedia , lookup
Chapter 5,9 &10: Review…How do we get Bio Diversity Biodiversity of life.. Habitats • Climate and Natural Selection What is Biological Diversity • Bio diversity refers to the variety of life forms in an area. – Expressed as # of species in an area – Or # of genetic types in an area Natural Selection • Some individuals may be better suited to the environment than others. • Those better able to survive and reproduce leave more offspring. • Their descendants form a larger proportion of the next generation. Mutation • Genes are inherited from one generation to the next – Genes made up of DNA – DNA made up bases A,C,G,T • How these letters are combined determines the massage passed to a cell • When cells divide – DNA is reproduced – Each cell gets a copy • If an error occurs in the reproduction of DNA it gets passed to new cells • DNA change = Mutation Mutation Natural Selection • Four primary characteristics – Genetic variability – Environmental variability causes pressure Adaptations determined – Differential success and reproduction – Survival and reproduction to pass on adaptations Basic Concepts of Biological Diversity • Genetic diversity: – total # of genetic characteristics of a specific species, sub species or group of species. • Habitat diversity: – the different kinds of habitat in a given unit area. • Species diversity: – Species richness- total # of sp – Species evenness- the relative abundance of sp – Species dominance- the most abundant sp Species Diversity Merely counting the number of species is not enough to describe biological diversity. The Evolution of Life on Earth • Earliest fossils 3.5 billion years old – Photosynthetic relative of bacteria – Released large amounts of oxygen into the atmosphere The Evolution of Life on Earth • Cambrian Period 600 million years- 500 my – Earliest multicellular organisms – Shells, gills, filters, efficient guts and circulatory system. – Life remained in oceans The Evolution of Life on Earth • Devonian Period – 420–360 million years ago – First animals on land = crossopterygian – Gave rise to the amphibians • Still tied to water for reproduction • Modern species include frogs, toads, newts, limbless water “snakes” Early Life on Land Innovations for life on land Structural support Avoid dessication and UV rays Means for exchanging gases with air A moist environment for reproduction system The Evolution of Life on Earth • Reptiles – – – – Freed from water by evolving a watertight egg Originate in the Carboniferous (375 mya) Wide spread by the Jurassic (185 mya) Two orders of dinosaurs that gave rise to mammal and birds. The Evolution of Life on Earth • Mammals – More capable brain and faster metabolism – Placental uterus one key to mammalian success Virginia California Island Biogeography • Islands have fewer species than continents – The smaller the island the fewer the species – The farther away from a continent the fewer the species – Theory of island biogeography Island Biogeography • Small islands tend to have fewer habitat types • A small population easily wiped out by a storm, flood, catastrophe or disturbance. – The smaller the pop the greater the risk of extinction • The farther an island is from the mainland the harder it is to reach. Environmental Factors that Influence Diversity Earth’s Biomes • 17 major biomes • Usually named for the – dominant vegetation type – dominant shape or form of the dominant organisms – dominant climatic conditions Biomes show up on Earth satellite image. Earth’s Biomes • Biological diversity varies among biomes – Generally declines with increasing latitude • Two theories – The more favorable the temperature and precipitation for life the more diversity. – Greater the variability of climate, the lower the diversity Tundra • Treeless plains that occur in harsh climates of low rainfall and low average temperature. • Dominant vegetation – Grasses, sedges, mosses, lichens, dwarf shrubs and mat-forming plants • Permafrost- permanently frozen ground – Extremely fragile, long recovery time • Soil-dark thick soil of peat, poorly decomposed Tundra Biome Taiga or Boreal Forest • Includes forests of the cold climates of high latitudes and high altitudes • Dominant vegetation – Conifers, especially spruces, firs, larches and some pines – Biodiversity is low (20 major species) • Dominant animals – Few lg mammals, sm carnivores, sm rodents – Many insects and migratory birds • Soil- thin, nutrient poor Moose in taiga biome. Taiga or Boreal Forest • Disturbances common – Fire, storms, insects • Contain some of Earth’s largest remaining wilderness areas. • Commercial value Temperate Deciduous Forests • Occur in climates somewhat warmer than those of boreal forest. • Dominant vegetation – Tall deciduous trees (maple, beech, oak, hickory, and chestnut) • Dominant animals – Tend to be small mammals – Birds and insects • Few undisturbed stands of forest left • Soil-fertile, rich, Temperate Rain Forest • Occur where temperatures are moderate and precipitation exceeds 250 cm/year. • Dominant vegetation – Evergreen conifers (some of the tallest trees in the world) • Low diversity of plants and animals • Important economically and culturally Temperate Rain Forest Temperate Grasslands • Occur in regions too dry for forests and too moist for deserts. • Dominant vegetation – Grasses and flowering plants • Many converted to agriculture – deep, rich soils • Highest abundance and greatest diversity of large mammals – Grasses and grazers evolved together Fire is important for the maintenance of Temperate Grasslands Tropical Rain Forests • Occur where the average temperature and rainfall are high and relatively constant throughout the year. • Famous for their diversity of vegetation – 2/3 of known flowering plants – Many species of animals as well • Soils low in nutrients Tropical Rain Forest Deserts • Occur in the driest regions where rainfall is less then 50 cm/year. • Specialized vegetation, vertebrates and invertebrates. – Water conservers • Soils has low organic matter but abundant nutrients – Need only water to become productive Desert Biome Wetlands • Include freshwater swamp, marshes and bogs and saltwater marshes. – All have standing water • Dominant vegetation – Small tress (mangroves) to shrubs, sedges and mosses Wetlands • Soil has little oxygen – Bacteria that produce methane and hydrogen sulfide – Coal bed production • Dominant animals – Salt water marshes- Crabs, clams – Freshwater wetlands- insects, birds and amphibians Freshwaters • Freshwater lakes, ponds, rivers, and streams – Make up a very small portion of Earth’s surface – Critical for water supply, material transport • Dominants – Floating algae, phytoplankton – Abundant animal life Freshwater • Estuaries- areas at the mouths of rivers – Rich in nutrients – Abundance of fish and important breeding sites for fish • Freshwater among the most important biomes for life’s diversity. Intertidal Areas • Areas exposed alternately to air during low tide and ocean waters during high tide. • Constant flow of nutrients into and out of area. – Rich in life • Susceptible to pollution • Adaptation to disturbances is essential to survival in this biome. The Process of Ecological Succession • Recovery of disturbed ecosystems can occur naturally, through a process of ecological succession. • Primary succession – The initial establishment and development of an ecosystem where one did not exist previously • Secondary succession – Reestablishment of an ecosystem following disturbance Examples of primary succession after a lava flow and at the edge of a receding glacier. Secondary successionfrom abandoned field to mature forest Patterns of Succession • When succession occurs it follows certain general patterns. – Three examples include dunes, bog and abandoned farm field Dune Succession • Sand dunes continually formed along sandy shores. – Then breached and destroyed by storms • After dune forms – First to be established are grasses – Grass runners stabilize dunes – Other species seeds may germinate and become established Dune Succession • Plants of early succession tend to be – Small, grow well in bright light, and withstand harshness of environment • Over time larger plants can become established – Eastern red cedar, eastern white pine – Beech and maple later on Bog Succession • A bog is an open body of water with surface inlets but no surface outlets. • Succession begins with – Sedge puts out floating runners – Wind blows particles into the mat of runners – Seeds that land on top don’t sink in the water and can germinate – Mat becomes thicker and shrubs and trees can grow Bog Succession • The bog also fills in from the bottom – The the shoreward end floating mat and sediment will meet, forming a solid surface. – Farther from shore all the vegetation is still floating Old-Field Succession • A great deal of land cleared for farming in the 18th and 19th centuries – That land now allowed to go back to forest • Succession – The first plants to enter the farm land are small plants adapted to harsh and variable conditions. – After they are established larger plants move in. These habitats are constantly changing General Patterns of Succession • Common element include the following – 1. An initial kind of vegetation specially adapted to the unstable conditions. • Typically small • Help stabilize physical environment – 2. A second stage with plants still of small statute, rapidly growing, with seeds that spread rapidly. General Patterns of Succession – 3. A third stage in which larger plants, including trees, enter and begin to dominate the site. – 4. A forth stage in which mature forest develops. General Patterns of Succession • Successional stages – Early (1 and 2), middle, and late • Similar patterns seen with animals and other life-forms at each stage. – Species characteristic of early stage are called pioneers – Late-successional species tend to be slowergrowing and longer-lived General Patterns of Succession • In early stages of succession – Biomass and biological diversity increase • In middle stages – Gross production increase and net production decrease – Organic material in soil increases, as does chemical element storage Succession and Chemical Cycling • The chemical storage capacity of soils varies w/ average size of the soil particle. – Large coarse particles, like sand, have a smaller total surface area and can store a smaller quantity of chemical elements. – Smaller particles, like clay, store greater quantity of chemical elements. • Soils store large quantities of c.e. but not as readily available as those in living organisms. Species Change in Succession • Earlier and later species in succession may interact in three ways – Facilitation – Interference – Life history differences • If they don’t interact the result is chronic patchiness Interaction between Species • Competition – The outcome is negative for both groups • Symbiosis – Close relationship between two organisms parasitism, commensalism, muturalism • Predation and parasitism – The outcome benefits one and is detrimental to the other. Competitive Exclusion Principle • Two species that have exactly the same requirements cannot coexist in exactly the same habitat. – E.g. British Red Squirrel and American Grey Squirrel Symbiosis • Describes a relationship between two organisms – beneficial to both – enhances each organism’s chance of persisting • Each partner called a symbiont • E.g. reindeer and bacteria in the gut – The result is food for reindeer, home for bacteria Lead into Chapter 12 Food Predation and Parasitism • Relationship is beneficial for predator or parasite and negative for prey or host. • Predation – One organism (predator) feeds on other live organisms (prey). • Parasitism – One organism (the parasite) lives on, in, or within another (the host). North Woods Ecosystem Population Fluctuations Carrying Capacity -------------------------------------------------K-species exponential r-species Lead into Chapter 12 Food Two Kinds of Biological Production Consider Food Webs • Autotrophs – Make their own organic matter from energy source and inorganic compounds – Primary production – Most photosynthesize, some chemoautotrophs • Heterotrophs – Cannot make their own organic compounds and must feed on other living things – Secondary production The Food Web of the Harp Seal • Food webs are complex because most species feed on several trophic levels. • Harp seal (shown at 5th level) – Feeds on flatfish (4th level) – But also feed on foods from 2nd – 4th – A species that feeds on several levels placed in a category one above the highest level it feeds on. Chemosynthetic Energy Flow in the Ocean • Chemosynthetic organisms make their own food from energy in sulfur compounds. – Sulfur-laden water is emitted from hot water vents – Rich biological communities surround the vents – Clams, mussels, crabs, limpets, fish, octopuses and giant worms. Balance of Nature • Since the second half of the 20th century ecologist have learned that nature is not constant. – All ecosystems undergo change – Species adapted to and need change • Dealing with change poses questions of human value – Controlling and managing fire Community Level Interactions • Indirect and more complicated community wide affects species have on one another. • Sea otter of the Pacific Ocean – Came close to extinction because of over hunting for fur – Feed on shellfish (abalone, sea urchins) – Where sea otters abundant kelp beds abundant and few sea urchins – Otters affects the abundance of kelp Community Level Interactions • Sea otters have community level effect – Where more kelp is present more habitat for many species • Keystone species – A species that has a large effect on its community or ecosystem • Holistic view – Ecological community is more than the sum of its parts