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Do Now: 1. Identify each animal & identify each as either a primary consumer or secondary consumer. 2. Identify the relationship between them. 3. Explain how these organisms are important to each other. Do Now: 1. primary consumer & secondary consumer 2. Predator/Prey relationship. 3. Importance in terms of population control/balance/health/evolution. Chapter 5: Ecosystems & living organisms Evolution • A process of change through time Theory of Evolution 1. Suggests that existing forms of life on earth have evolved from earlier forms over long periods of time 2. Evolution accounts for the differences in structures, function, and behavior among life forms as well as changes (C) Charles Darwin 1. Overproduction • Within a population, there are more offspring produced in each generation than can possibly survive. 2. Competition • Natural resources; like food, water, and space available to a population is limited • Because there are many organisms with similar nutritional requirements, there must be competition between them for the resources needed to survive (C) Darwin • Charles Darwin devised a theory of evolution based on variation and natural selection as seen in the Galapagos islands. • Included in his theory were six main ideas: 1. Overproduction 2. Competition 3. Survival of the Fittest 4. Natural Selection 5. Reproduction 6. Speciation Do Now: • List the six main ideas of Darwin’s Theory of Evolution: 1. 2. 3. 4. 5. 6. Competition 1. Different species living in the same environment, or habitat, may require the same resources. When the resources are limited, competition occurs among the species. Intraspecific: competition within a population Competition 2.Competition- is the struggle between different species for the same limited resources. The more similar the needs of the species, the more intense the competition. Interspecific: competition between different species. Competition 3.Each species occupies a niche in the community. A niche is the role the species plays, and includes the type of food it eats, where it lives, where it reproduces, and its relationships with other species. Competition 4.When two different species compete for the same niche in a community, the weaker species is usually eliminated establishing one species per niche in a community. Do now: • How do the processes of _______ contribute to natural selection? – – – – overproduction of offspring individual variation among individuals in a population environmental limits on population growth (natural selection) differential reproductive success • HINT: Do not simply describe these four observations; connect them into an integrated response. Do Now: Sample Answer • Because more offspring are produced in a population than survive to reproduce and because individuals vary within the population, some individuals will be better adapted (more fit) for the current environmental conditions. These individuals have a greater likelihood of reproducing and passing their fitness to their offspring. As a population approaches the carrying capacity of its environment, the individuals with the greatest fitness are most likely to survive and reproduce. • This is an ongoing process as organisms respond to changes, however minute, in their Do Now: • Define ecological niche and explain the role of limiting resources in the determination of an organism's ecological niche. Do Now: Answer • Every organism is thought to have its own role, or ecological niche, within the structure and function of an ecosystem. An ecological niche is basically determined by all of a species’ structural, physiological, and behavioral adaptations. Any resource at a suboptimal level relative to an organism’s need for it or at a level in excess of an organism’s tolerance for it is a limiting resource. • The resources can include mineral content of soil, extremes of temperature, and amount of precipitation. The limiting resources can affect part of an organism’s life cycle. For example, the ring-necked pheasant was introduced in North American but didn’t survive in the southern United States because the eggs can’t develop properly in the warm southern temperatures. Limiting Factors Gause’s Experiments Limiting Factors Gause’s Experiments Which type of Competition? Interspecific Competition! Competitive Exclusion: one species is excluded from a portion of a niche by another as a result of interspecific competition. (2 species with identical niches can’t coexist.) Do Now: • The Norway rat and the black rat were both introduced to this country from Europe. The Norway rat is found only in cities and inhabits most cities in the U.S. The black rat can live in cities and rural areas but in New Jersey is ONLY found in rural areas. Some cities in New Jersey, which previously had only black rats, now have only Norway rats. Discuss this phenomenon in terms of competitive exclusion, resource partitioning and limiting resources. Do Now Answers: • No two species can indefinitely occupy the same niche in the same community because competitive exclusion eventually occurs. • Interspecific competition for limiting resources will result in the competitive exclusion of one of the species. In this particular case, the black rat was driven from the cities through competition of resources with the Norway rat. • The two species of rats do not show evidence of resource partitioning that would allow the rats to coexist in the same habitat. Instead the black rat has confined its habitat to the rural areas while the Norway rat has taken over city existence. Limiting Factors Gause’s Experiments Variations among members of a population make some of them better adapted to the environment than others It is generally the best-adapted individuals that will survive. The environment is the agent of natural selection determining which species will survive. 3. Survival of the Fittest Survival of the Fittest Survival of the Fittest (4) Natural Selection Traits which are beneficial to the survival of an organism in a particular environment tend to be retained and passed on, and therefore, increase in frequency within a population. (variation) (4) Natural Selection Traits which have low survival value to an organism tend to diminish in frequency from generation to generation. (4) Natural Selection If environmental conditions change, traits that have low survival value may now have a greater survival value. Therefore, traits that prove to be favorable under new environmental conditions will increase in frequency. (differential reproductive success) Industrial Melanism Do Now: • Charles Darwin concluded that inherited traits favorable to survival would be preserved over time. • Look at this graph of a DDT spray program aimed at eliminating a mosquito species. Explain the data contained in the graph at point I –VI and relate the graph’s data to Darwin’s conclusion. • • • • The mosquito population is at a sustainable level (I). When DDT is initially introduced into the population, the population of mosquitoes declines (II) as most of the mosquitoes have no resistance to the DDT chemical. However due to natural variations within the mosquito population, a few mosquitoes do have a trait (resistance to DDT) that improves their chances of survival and reproductive success (III). Those individuals that possess the most favorable combination of characteristics (better adapted for the DDT environment) are more likely to survive, reproduce, and pass their traits to the next generation – differential reproductive success (IV). As the spray program ends, the mosquito population grows (V) until it reaches a size where the limiting resources of the environment would keep the extent of the population level (I and VI). Answer Do Now: How did an Insects resistant to insecticides occur? Ex: Insects resistant to insecticides 1. Genetic make-up of some insects make them resistant to the effects of insecticides 2. Before the widespread use of insecticides, this trait was of no particular survival value 3. With the increased use of insecticides, this trait developed a very high survival value 4. Therefore, insects with resistance to insecticides survived and reproduced much more successfully than those lacking the trait 5. As a result, the frequency of insecticide resistance has increased greatly in insect populations Important! The trait already exists within the genetic makeup of the organism. Ex: Rats resistant to rodenticides Not Immune! 5. Reproduction • Individuals that survive and then reproduce transmit these variations to their offspring Do Now: • The diagram represents a tree containing three different species of warbler, A, B, and C. Each species occupies a different niche. A fourth species, D, which has the same environmental requirements as species B, enters the tree at point X. Members of species B will most likely (1.) live in harmony with species D (2.) move to a different level and live with species A or species C (3.) stay at that level but change their diet (4.) compete with species D Natural selection can favor Resource Partitioning: differences in resource use among species. Resource Partitioning Effect of community complexity on Species richness 6. Speciation • The development of a new species occurs as variations or adaptations accumulate in a population over many generations. • Ex: primitive human present man? • Canis lupus Canis familiaris? Speciation? “El Chupacabra” Speciation Prehistoric Giant Sloth & modern 3 toed Sloth How does the Iiwi and Lobelia demonstrate Coevolution? Answer • Coevolution is the mutual evolutionary influence between two species (the evolution of two species totally dependent on each other). Predation • Predators exert strong selective pressures upon their prey. Coevolution is the result. • Example: • Brain size in Sperm whales = 7,820g in response to Giant Squid. • Human = 1,500g CoEvolution • Symbiosis is a result of Coevolution. • Plants and pollinators proboscis – Honeybee hairy bodiespollen transport – Honeycreepers curved bill Convergent Evolution • Organisms evolve similar structures though they are not closely related. • Ex: Human eye • & the Squid eye • • Do Now: Consider species A and B within an ecological community. These species might interact in various ways that represent gains, losses, or no effect to the two species. In 4 of the 6 cells below, enter the terms that describe the types of interactions might be occurring between species A and B in the community. SPECIES B SPECIES A Positive Positive Negative Neutral Negative Neutral Do Now: SPECIES A SPECIES B Positive Negative Neutral Positive mutualism Predation (Species A is prey) Parasitism (Species A is host) Competitive exclusion of Species A commensalsim Negative Predation (Species A is predator) Parasitism (Species A is parasite) Competition Limiting resources -- Neutral commensalism -- Resource partitioning Evolution of Diversity & classification The older 5 Kingdom system 1. 2. 3. 4. 5. Monera Protista Fungi Plant Animal • A dichotomous key is a tool that allows the user to determine the identity of items in the natural world, such as trees, wildflowers, mammals, reptiles, rocks, and fish. • Keys consist of a series of choices that lead the user to the correct name of a given item. "Dichotomous" means "divided into two parts". Therefore, dichotomous keys always give two choices in each step. Step 1 The organism is unicellular The organism is multicellular Step 2 Is prokaryotic Is Eukaryotic Step 3 I am autotrophic I am heterotrophic Step 4 I absorb my nutrients from the environment I ingest my nutrients Step 5 Primitive bacteria (Extremophyles) True bacteria Go To Step 2 Go To Step 3 Monera (to further break down) Go To step 5 Protista Green Plants Go To Step 4 Fungi Animals Archeobacteria Eubacteria Six -dom Taxonomic System 3 Major Domains Rotting Log Community: Do Now: • Draw a flow diagram of an old field undergoing succession. What type of succession is this? Do Now answer: • The change in an old field over the years is an example of secondary succession. • First year after cultivation ceases, crabgrass dominates ->second year, horseweed ->third year, other weeds such as broomsedge, ragweed, aster ->years 515, pines -> oaks and other hardwoods Ecosystem Formation • Ecosystems tend to change over a long period of time until a stable ecosystem is formed. • Both the living and nonliving parts of an ecosystem change. Ecological Succession • The replacement of one kind of community with another is called ecological succession. • The kind of stable ecosystem that develops in a particular geographical area depends on climate. • Pioneer organisms- are the first plants to populate an area. Lichens and algae may be pioneer organisms on bare rock. • Climax Communities- Succession ends with the development of a climax community in which the populations of plants and animals exist in balance with each other and the environment. Ecological Succession Grasses shrubs poplars (cottonwoods) pine trees oak 2. Symbiotic Relationships • Different organisms may live together in a close association. • This is known as symbiosis. • There are three types: 1. Commensalism 2. Mutualism 3. Parasitism • KEY: + = benefits - = harmed o = not affected Commensalism • (+ , o) • In this relationship, one organism benefits and the other is not affected. • Ex: barnacles on a whale Commensalism (+ , o) • Epiphytes (mosses, orchids, ferns, bromeliad ) attach themselves to tree bark and obtain their nutrients without harm to the trees. Mutualism • (+ , +) • In this relationship both organisms benefit from each other. • Ex: protozoan living in the digestive tract of termites. • Wood eaten by termites is digested by the protozoan. The nutrients released supply both organisms. Mutualism • (+ , +) • In this relationship both organisms benefit from each other. • Ex: Mycorrhizae (+ , +) In this relationship both organisms benefit from each other. • Ex: Red Cedar and mycorrhizal fungi. Parasitism • (+ , - ) • In this relationship, the parasite benefits at the expense of the host. • Ex: athlete’s foot fungus on humans tapeworm and heartworm in dogs. Parasitism • (+ , - ) • Pathogens (disease causing agents) are parasites that often cause the death of its host. • Crown gall disease in plants. Parasite/Host Relationship Guinea worm/Human Parasite/Host Relationship Sea Lamprey/Fish Parasitism • Parasite/Host Relationship • Varroa mite/Honeybee Tracheal mites Do Now: • Define keystone species and discuss two examples of organisms that are keystone species. Do Now Answer: • A keystone species is vital in determining the nature and structure of an entire ecosystem. • The keystone species is often a predator, which exerts a profound influence on a community in excess of that expected by its relative abundance. • Keystone species are usually not the most abundant species in the ecosystem. • One examples: – the fig tree in a rainforest ecosystem. The fig tree is important in sustaining fruit-eating vertebrates. While a supplemental fruit normally, during the time of year when other fruits are less plentiful, the fig trees sustain the fruit-eating vertebrates such as the monkeys, birds, and bats. – in a different ecosystem is the gray wolf. The gray wolf is a top predator. If it were eliminated from the ecosystem, the population of deer and other herbivores would increase exhibiting grazing pressure and a loss of vegetation. That loss would result in shortfall of habitat and food for smaller animals and insects, thus decreasing the biodiversity of the ecosystem. Keystone species • These determine the nature and structure of an entire ecosystem. Usually found in small numbers but have a key influence. • Examples: Wolves, Fig Trees Do Now: • Gray wolves originally ranged across North America but were removed from Yellowstone and the American Rocky Mountains in the 1930’s. The gray wolf was listed as an endangered species in 1974. In an effort to increase their numbers, a small number of gray wolves were re-released into Yellowstone • National Park in 1995. The wolves prey on elk, deer, moose, and bison. They have decimated some coyote populations and also threaten some rancher’s livestock. – Identify and describe TWO major causes for the original decline of this species. – Describe TWO measures that have been taken to protect this species. – Make an ecological argument for protecting the gray wolf OR make an economic argument against protecting the gray wolf. Do Now Answers: • Originally the gray wolf was trapped, poisoned, snared, and hunted to extinction in most places by fur traders and ranchers. • Under the provisions of the Endangered Species Act, wolves in the northern Rocky Mountains were listed as endangered in 1974. Because the gray wolf is on the endangered species list, the Endangered Species Act forbids killing of an endangered species. In addition, a program to reintroduce a small number of gray wolves into Yellowstone National Park has helped the population of wolves thrive. In the Yellowstone park area, the wolf was declared an “experimental nonessential in the area so that ranchers can kill Yellowstone wolves that attack their cattle and sheep, and federal officers can remove any wolf that threatens humans or livestock. • FOR: The intensive hunting by wolf packs has helped reduce the all-time high Yellowstone’s elk population, which in turn has relieved heavy grazing pressure by elks on aspen, willow, and cottonwood. As a result of a more lush and varied plant composition, herbivores such as beavers and snow hares have increased in number, which in turn support small predators such as foxes, badgers, and martens. • The reduction of the coyote population has allowed an increase in coyote Case Study "The Effects of Coyote Removal in Texas: A Case Study in Conservation Biology" by Margaret Carroll Department of Biology Framingham State College Case Study The Wolf, the Moose, and the Fir Tree: Who Controls Whom on Isle Royale? A case study of trophic interactions by Gary M. Fortier Department of Small Animal Science Delaware Valley College Do Now: Reintroduction plans? Grand Mesa Colorado is drawing up a proposal to adopt the procedures used by Yellowstone National Park To reestablish a Grey Wolf population. What factors would you need to consider for this plan to be successful. Do Now Answers: things to consider… Yellowstone National Park • Mountain lions • Major Prey species: – – – – – – Bison Moose Elk (migratory) Mule Deer White Tail Deer Antelope • Large protected geography • Varied topography (elevations) Grand Mesa Colorado (Western CO) • Mountain lions • Major Prey Species – Elk (migratory) – Mule Deer • Major Cattle Farming • Fragmented lands – Private + commercial properties Do Now: • List and describe three animal prey defenses against predators. Answer: • When confronted by a predator, animals have many defensive adaptations. Woodchucks flee into their underground burrows. Porcupines and turtles have mechanical defenses, barbed quills and hard shells. • Some animals live in groups for protection. This social behavior decreases the likelihood of a predator catching one of them. The South American poison arrow frog has poison glands in its skin and bright warning coloration. Other animals use camouflage to blend into their surroundings Do Now: • Explain the circumstances under which a prey organism would have coloration that would make it more visible to a predator. • Include three specific examples of organisms that use this strategy. Do Now Answers; • If a prey has a chemical defense such as a poison, toxin, or acrid spray, then it can afford to have a bright warning coloration that would caution experienced predators to avoid it. For example the white stripe on a black skunk is very recognizable and associated with acrid chemicals sprayed from its anal glands. • The poison arrow frog is brightly colored and has poison glands in its skin. Likewise some poisonous snakes have bright coloration Defensive Adaptations • Defenses against Predators – Warning coloration • poison, toxin, or acrid spray – Camouflage • Mimicry • Cryptic • Plant defenses against herbivores – Thorns, toxins, poison berrys Defensive Adaptations in Animals Mimicry: resemblance to another species. • Ex: Io moth Defensive Adaptations in Animals Mimicry: resemblance to another species. • Ex: Monarch and Vicorory Butterfly Danaus plexippus Limenitis archippus Observational Extra credit: Identify these 2 snakes. How do you know which one is venous? Defensive Adaptations in Animals Mimicry: resemblance to another species. • Ex: Coral snake vs. King Snake Defensive Adaptations in Animals • Chemical defenses: Sprays or by… • Warning Coloration: avoidance of predators by unpalatable animals. – Ex: Poison Dart Frog. Defensive Adaptations in Animals Crypsis (cryptic coloration) (Camouflage): Blending into the surroundings for avoidance of predators by palatable animals. • Ex: Leafy Sea Dragon Defensive Adaptations in Animals Crypsis(cryptic coloration) (Camouflage): Blending into the surroundings for avoidance of predators by palatable animals. • Ex: Weedy Sea Dragon What do you see? What do you see? What do you see? Predator/Prey Relationships! Predator/Prey Relationships Data collected from fur pelts from the Hudson Bay Company Studies have shown that Endocrine changes in populations may produce behavioral changes which tend to limit population growth. Therefore all population changes may not be due to predator/prey relationships alone. Green Anole (indigenous) restricted by the Brown Anole (foreign). Green Anole Brown Anole Brown Anoles affected the realized Niche of the Green Anoles. Cichlids (indigenous) restricted by the Nile Perch (foreign). http://www.african-angler.co.uk/210.jpg Lake Victoria is about the size of the Republic of Ireland, forms the headwaters of the River Nile.