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Chapter 5: Evolution and Community Ecology Mr. Manskopf Notes Can Also Be Found at http: //www. manskopf. com
Section 1: Evolution ►Describe the four primary mechanisms of biological evolution ►Describe how speciation and extinction affect the diversity of life on Earth. ►TERMS: evolution, gene mutation, genetic drift, natural selection, fitness, adaptation, artificial selection, speciation, extinction.
Incredible Diversity of Life ► 1. 5 to 1. 8 million known species ► Possibly 13 -20 million ► Tropical Rain Forests, Coral Reefs and everywhere else
Evolution ►What YOU? makes you, What makes each species unique and different?
Genes ►Sequences of DNA codes for each particular trait ►Tall, small, blue eyes, human, goldfish, pine tree ►Evolution is a change of genes over time
Evolution ►“Change over time” ►Change of Gene Pool over time ►Why would genes change over time?
4 Ways Evolution Occurs ►Mutation ►Migration ►Genetic Drift ►Natural Selection
Mutation Accidental change in DNA that can give rise to variation among individuals
Migration Movement of individuals into (immigration) or out of (emigration) a population Sometimes called “Gene Flow”
Gene Flow (Migration)
Genetic Drift Evolution that occurs by chance • Natural Disasters • Run in with human nets, etc.
Natural Selection ► Process by which traits useful for survival and reproduction are passed on more frequently than those that are not
3 Conditions for Natural Selection (1) Organisms produce more offspring than can survive. • Nature has limitations (limiting factors) • Struggle for survival
3 Conditions for Natural Selection (2) Individuals vary in characteristics, some of which are heritable ► Not every species is same ► Some fish are faster, darker, smaller ► Genes different ► Heritable Differences
3 Conditions for Natural Selection (3) Individuals vary in fitness, or reproductive success ► Survival of Fittest ► Fittest for its environment ► Adaptation: an inherited trait that increases an organisms chance of survival and reproduction.
http: //www. youtube. com/watch? v=xkw. RTIKXaxg ► Travel to Ecuador to see how the process of natural selection operates
Adaptations Desert plants have small or no leaves at all The insect that blends in and is able to survive may be more likely to reproduce.
Big ears of desert jack rabbit allow it to cool off quickly White coat of Adaptations polar bear helps in hunting Results of Long neck of giraffe natural allow it to reach food selection all around us NATURE SELECTS
Did You Know? Darwin privately researched natural selection for two decades before publishing On the Origin of Species.
Impacts of Natural Selection: Resistance
Resistance: the ability of one or more organisms to tolerate a chemical designed to kill it ► Able to survive and reproduce ► Pesticide resistance ► Antibiotic resistance
Why is this a problem ?
Artificial Selection: How Humans Use Evolution Artificial Selection: selective breeding of organisms by humans ►Selecting certain desirable traits ►Size, sweetness, color, shape, ►Very common
Artificial Selection Selecting desirable traits and breeding only those with those traits.
Speciation: How did we get millions of species?
Speciation • Process by which new species are generated • Can occur in a number of different ways; the most important way is called allopatric speciation– Geographic Isolation • Has resulted in every form of life on Earth— today and in the past
The canyon is a barrier to dispersal by small mammals, and as a consequence the isolated populations can diverge.
http: //www. youtube. com/watch? v=S 4 wn. Jp 6 sq_I
Extinction • The disappearance of species from Earth • Generally occurs gradually, one species at a time, when environmental conditions change more rapidly than the species can adapt • There are five known mass extinction events, each of which wiped out a large proportion of Earth’s species.
Biodiversity has increased over time, but mass extinctions are also natural events (5 major events) How do we get this data? Did You Know? During the Permo-Triassic extinction 250 million years ago, 70% of all land species and 90% of all marine species went extinct.
Extinctions ► Species gone forever ► NORMAL ► Mass Extinction: short period of time when large number of species go extinct (65 MYA) ► Currently in mass extinction…caused by humans ► Rapid climate change
Extinctions The zebra mussel has completely displaced 20 native mussel species in Lake St. Clair.
Section 1: Evolution Review ► Describe the four primary mechanisms of biological evolution ► Describe how speciation and extinction affect the diversity of life on Earth. ► TERMS: evolution, gene mutation, genetic drift, natural selection, fitness, adaptation, artificial selection, speciation, extinction
Section 1 Quiz 1) Which of the following best describes a successful individual in evolutionary terms? A. A successful individual possesses traits that are different from the traits of the rest of the population. B. A successful individual produces many offspring that possess unique traits. C. A successful individual is well adapted to its environment and produces offspring that survive to pass on genes. D. A successful individual will be well adapted to its environment and produce a few high quality offspring. A. A successful individual possesses traits that are different from the traits of the rest of the population.
2) In the history of the world, how many mass extinctions have occurred? A. 5 B. 7 C. 10 A. 5 D. 13
3) In a mass extinction, the rate of extinction exceeds A. 99 percent. B. 85 percent. C. the rate of environmental change. D. the rate of background extinction
4) A reintroduced population of wolves in a national park is 90% grey and 10% black, consistent with the wolf population in other regions. After several generations in isolation, the national park’s wolf population is 60% grey and 40% black. The wolf population has likely experienced A. natural selection. B. genetic drift Evolution that occurs B. genetic drift. by chance C. mutations. D. migration.
5) When the environment changes too quickly for an organism to adapt, what will occur? A) Evolution B) Speciation C) Genetic Drift D) Extinction D. Extinction
True or False 6) Two populations of a deer species are separated when a glacier forms. After the glacier melts, the two populations have become different species. This is an example of allopatric speciation. TRUE
Short Answer 7) A disaster wipes out 50 percent of a small population of birds. Prior to the disaster, about half the birds had a green wing patch and half had a blue wing patch. Several generations after the disaster, only 10% have a blue wing patch, and 90% have a green wing patch. What do you infer happened, and why? The bird population experienced genetic drift as the result of a sudden catastrophe. The disaster reduced genetic diversity in the population and changed the proportion of birds with a green wing patch vs. a blue wing patch.
Short Answer 8) Pronghorn are a species of extremely fast hooved mammal that live on the plains of western North America. They are so fast that no current North American predator can catch them. During the ice age, cheetahs occupied North America. Speculate about how pronghorn became so fast. Pronghorn probably evolved in an evolutionary “arms race” with the cheetah population. They became faster and faster to escape from cheetahs, which were probably fast enough to catch them.
Section 2: Species Interaction ► Discuss the factors that influence an organisms niche ► Compare and contrast predation, parasitism, herbivory ► Describe mutualism and commensalism ► TERMS: niche, tolerance, resource partitioning, predation, coevolution, parasitism, symbiosis, herbivory, mutualism, commensalism.
Species Interaction What resources are the plants in this picture competing for? Competition for resources all around us
► Describes Niche an organism’s use of resources and functional role in a community ► Habitat ► Food It Eats ► When, How Reproduces ► What organisms does it interact with
Niche Impacted By Tolerance and Competition • Affected by an organism’s tolerance —its ability to survive and reproduce under changing environmental conditions • Often restricted by competition
Fundamental vs. Realized Niche Fundamental = Without competition Realized = With competition (restricted niche)
►Organisms Competition compete when they seek the same limited resource. ►In rare cases, one species can entirely exclude another from using resources. ►To reduce competition, species often partition resources, which can lead to character displacement.
► The zebra mussel has completely displaced 20 native mussel species in Lake St. Clair.
Predation (+/-) ► The process by which a predator hunts, kills, and consumes prey ► Causes cycles in predatory and prey population sizes
Predation ► Defensive traits such as camouflage, mimicry, and warning coloration have evolved in response to predator-prey interactions.
Predation ► Some Rough-Skinned Newt Did You Know? A single rough- skinned newt contains enough poison to kill 100 people. Unfortunately for the newt, its predator, the common garter snake, has coevolved resistance to the toxin. predator-prey relationships are examples of coevolution, the process by which two species evolve in response to changes in each other.
Coevolution The Madagascar star orchid produces nectar at the bottom part of its slim, footlong throat. After observing a specimen, Charles Darwin predicted the existence of a moth with a proboscis long enough to reach that nectar. Sure enough, decades later the giant hawk moth of Madagascar was discovered.
Parasitism and Herbivory (+/ –) • Parasitism: One organism (the parasite) relies on another (the host) for nourishment or for some other benefit • Herbivory: An animal feeding on a plant
Parasitism and Herbivory (+/ –) Malaria is a disease caused by a parasite called Plasmodium that is spread to humans by the bite of an infected Anopheles mosquito.
Parasitism and Herbivory (+/ –)
Mutualism (+/+) and Commensalism (+/0) • Mutualism: a relationship in which two or more species benefit • Commensalism: a relationship in which one species benefits while the other is unaffected
Mutualism (+/+) and Commensalism (+/0) Clown Fish and Sea Anemones demonstrate mutualism because Anemones provide the Clown Fish with protection from predators while Clown fish defend the Anemones from Butterfly fish who like to eat Anemones.
Mutualism (+/+) and Commensalism (+/0) Barnacles adhering to the skin of a whale or shell of a mollusk
Section 2 Review Species Interaction ► Discuss the factors that influence an organisms niche ► Compare and contrast predation, parasitism, herbivory ► Describe mutualism and commensalism ► TERMS: niche, tolerance, resource partitioning, predation, coevolution, parasitism, herbivory, mutualism, commensalism.
Section 2 Quiz 1) Madagascar, several species of lemur eat bamboo, but each species specializes in one part of the bamboo—one species eats mature bamboo stalks, one species eats bamboo shoots, and one species eats leaves. This is an example of ► A. speciation. ► B. resource partitioning. B. Resource ► C. competition. Partitioning ► D. niche partitioning.
2) In the example above, one lemur species eats only bamboo shoots. Bamboo shoots contain a high level of cyanide, a toxic chemical. This lemur species has developed a tolerance for a certain amount of cyanide. What do you think will happen over time? A. The level of cyanide in the bamboo population will increase. B. The level of cyanide in the bamboo population will decrease. C. The level of cyanide in the bamboo population will remain the same. D. The level of cyanide in the lemur population will decrease. A. The level of cyanide in the bamboo population will increase.
3) Two species of finch live in the same environment. Over time, one develops a larger beak to consume larger seeds, while the other develops a narrow beak to consume more delicate seeds. This is an example of A. resource partitioning. B. character displacement. C. coevolution. D. competitive exclusion. C. coevolution.
4) An interaction in which an individual of one species kills and consumes an individual of another is called A. predation. B. parasitism. C. herbivory. D. symbiosis. A. predation
5) In the western United States, at the southern edge of their range, moose are sometimes so severely infested with ticks that they die. The tick/moose relationship is best described as A. predatory. B. parasitic. C. symbiotic. D. mutualistic. B. parasitic.
6) A beehive depends on pollen from flowers to survive. Flowers depend on bees to pollinate them. The relationship among these two sets of organisms is A. parasitic. B. commensalist. C. herbivory D. mutualistic.
7) A niche restricted by competition is a A. fundamental niche. B. realized niche. C. resource partitioned niche. D. displaced niche. B. realized niche
8) A deer browsing on a shrub is an example of A. predation. B. parasitism. C. herbivory. D. photosynthesis. C. herbivory.
True or False You have many species of bacteria living in your gut that help you with digestion. This relationship is best defined as commensalism. False: Mutualism
Short Answer 9) Explain the difference between mutualism and commensalisms, with examples. In mutualism and commensalism, both species are unharmed. In mutualism, both species benefit, as in the example of the hawk moth pollinating the flower; the flower is pollinated and the moth is fed. In commensalism, one species benefits while the other doesn’t experience a negative or a positive effect. Trees providing shade and moisture to desert shrubs is an example of commensalism.