Biodiversity

1. Biodiversity Biodiversity is the diversity of life forms in an environment. Biodiversity is an important indicator of environmental health. Both evolution and extinction account for the biodiversity on Earth today.

2. Marine Biodiversity

3. What are the 3 LEVELS OF BIODIVERSITY? • 1. Ecosystem Diversity • The variety of ecosystems within a region. • 2. Species Diversity • The variety of species within an ecosystem. • 3. Genetic Diversity • The variety of genes within a given species. • Every individual organism is distinguished from every other organism by the differences in their genes.

4. Measures of Species Diversity • An estimated 10 million species inhabit the Earth today. • How does a scientist measure the species diversity at a local or regional scale? • Species Richness • Species Evenness Species Diversity is dependent on these two factors.

5. Species Richness • Species Richness is the number of species in a given area. • It is used to give an approximate sense of the biodiversity of a particular place.

6. Species Evenness • If a scientist wanted to know relative proportions of individuals within the different species, then the scientist would use…species evenness. • Species evenness tells whether a particular ecosystem is numerically dominated by one species or whether all of its species have similar abundances. • High species evenness: Its species all represented by similar #’s of individuals. • Low species eveness: 1 species is represented by many individuals and others are represented by few individuals. • FIGURE 4.3, page 84

7. Homework • What is the difference between species richness and species evenness? Why are they both important? • Biodiversity exists at three scales. What are they? Define each.

8. If all we rely on is a small number of species for our essential needs, why should we care about the millions of other species in the world?

9. “Value” of a Species • Instrumental Value • The species has worth as an instrument or tool that can be used to accomplish a goal. • Idea of how much economic benefit a species brings to humans. • Lumber • Pharmaceutical drugs

10. “Value” of a Species (cont.) • Intrinsic Value • The species has worth independent of any benefit it may provide to humans. • Example: The moral value of an animal’s life • This value can’t be quantified.

11. Ecosystem Services • The instrumental value of ecosystems lies in Ecosystem Services. • Ecosystem Services are the benefits that humans obtain from natural ecosystems. • Example: Agricultural ecosystem’s ability to produce food • Example: Wetland ecosystem’s ability to filter and clean the water that flows through • Can be assigned monetary values by economists

12. Biodiversity results from Evolution • Evolution: A change in the genetic composition of a population over time • Evolution depends on genetic diversity. • Evolution occurs at multiple levels. • Microevolution: evolution below the species level • Macroevolution: process when genetic changes give rise to new species, or to new genera, families, classes, or phyla

13. Genetic Diversity • Review: Genetic Diversity is the variety of genes among individuals of species. • Genes determine the range of possible traits (physical or behavioral characteristics) an organism can pass down to its offspring. • Genotype is the complete set of genes in an individual. • Genes you posses that code for eye color make up a part of your genotype. • Phenotype is the actual set of traits expressed in an individual. • Color of your eyes

14. What creates Genetic Diversity? • Mutation • If there is an occasional mistake in the copying process of DNA, then the mistake produces a random change in the genetic code. This change is a mutation. • Note: DNA is copied as cells divide and grow. Happens millions of times during a lifetime. • UV radiation from the Sun can cause mutations. • Mutations can be passed on to the next generation when they occur in cells responsible for reproduction • Most mutations are detrimental, Figure 4.4. • Sometimes a mutation improves an organism’s chances of survival or reproduction. • Recombination • Rearrangement of genetic material

15. Homework • Cornell notes, pages 86 – 90. • For the cornell notes, you will create 8 questions and answer each of them in complete sentences.

16. Evolution • Evolution occurs in three ways. • Artificial selection • Natural selection • Random processes

17. Artificial Selection • Artificial selection • When humans determine which individuals breed • Artificial selection is a way humans influence evolution. • Humans breed plants and animals for desired traits. • Example: Different breeds of domestic dogs were bred from the wolf by humans, Figure 4.5 on page 85. • Carefully controlled breeding • All dogs remain a single species. As a result, they can mate with one another and produce offspring.

18. Natural Selection • Natural Selection • Environment determines which individuals survive and reproduce. • The concept of evolution by natural selection did not become a theory until Alfred Wallace and Charles Darwin independently made sense of the idea species could evolve over time. • Darwin questioned why only a small fraction of all the species that had once existed had survived. He also questioned why only a small fraction of offspring produced in a population / year survived. • Led to him developing theory.

19. Natural Selection cont. Darwin’s Theory of Evolution 1. Individuals produce an excess of offspring. 2. Not all offspring can survive. 3. Individuals differ in their traits. 4. Differences in traits can be passed on from parents to offspring. 5. Differences in traits are associated with differences in the ability to survive and reproduce.

20. Natural Selection cont. • Natural selection favors… • Any combination of traits (adaptations) that improves an individual’s fitness. • Fitness: individual’s ability to survive and reproduce • Examples: Adaptations that allow plants to survive and reproduce in a particular environment. • In the desert  plant’s ability store excess water; evolved waxy or hairy leaves that reduce water loss; large taproots

21. Random Processes • Evolution can occur by nonadaptive processes. • Mutation • Genetic Drift • Bottleneck Effects • Founder Effects

22. Random Processes cont. • Mutations: The larger the population, the more opportunities there will be for mutations to appear within it. • The # of mutations accumulates over time = evolution occurs • Genetic Drift • A change in the genetic composition of a population over time as a result of random mating.

23. Random Processes cont. • Bottleneck effect • A reduction in the genetic diversity of a population caused by a reduction in its size. • Low genetic diversity in a population can cause several problems. • Increased risk of disease • Low fertility • Causes species to decline to extinction • Example: Cheetah has little genetic diversity due to bottleneck effect 10,000 years ago.

24. Random Processes cont. • Founder effect • Colonizing individuals will give rise to an island population that has a genetic composition very different from that of the original mainland population.

25. Homework • Find an example of the following random processes. • Genetic Drift • Bottleneck Effect • Founder Effect • You may use the examples in the book.

26. Range of Tolerance • All species have limits to the abiotic conditions they can tolerate. • Extremes of temperature • Humidity • Salinity • pH • Individuals will die if conditions move beyond the range of tolerance. • The suite of ideal conditions = the fundamental niche, Figure 4.8, page 89 • The range of abiotic and biotic conditions under which a species actually lives = realized niche

27. Species evolve adaptations to specific environmental conditions.What could happen to the species when there is a change in those environmental conditions?

28. Species Extinction • Species that can’t adapt to changes or move to more favorable environments will eventually go extinct. • 99% of the species that have ever lived on Earth are now extinct. • Avg. life span of species about 1-10 million years • WHY DO SPECIES GO EXTINCT?

29. Species Extinction cont. • 1. It may not be geographically possible for a species to move to a favorable environment. • Polar bear depends on sea ice (a vital habitat for the polar bear) • Allows to hunt seals • Rising global temps melts sea ice 3 weeks earlier in the Artic since 20 years ago • Male polar bears weigh on average 150 lbs. less than 30 yrs. ago

30. Species Extinction cont. • 2. A species may go extinct when the change happens so rapidly that the species doesn’t have time to evolve new adaptations. • Much of what is known about the evolution of life is based on fossils. • The fossil record has revealed 5 periods of global mass extinction. • Environmental Scientists apply the lessons learned to help predict the effects of the environmental changes taking place today.

31. SIXTH MASS EXTINCTION • Scientists have reached a consensus within the last 20 years that we are CURRENTLY experiencing a 6th global mass extinction. • Will 2-25% of species go extinct by 2020 as scientist believe? • There is an agreement among scientists this mass extinction has human causes. • Habitat Destruction • Overharvesting • Intro of Invasive Species • Climate change due to human activities • Emerging diseases

32. Levels of Complexity • Scientists study nature at the following levels of complexity. • The Individual • A Population • A Commmunity • An Ecosystem • The Biosphere

33. The Individual • Natural selection operates at the level of the individual. • The individual must survive and reproduce. • Natural Selection: Individuals better adapted to their environment tend to survive and reproduce more offspring.

34. A Population • Evolution occurs at the level of the population. • Population: A population is composed of all the individuals that belong to the same species and live in a given area for at a particular time. • Evolution: A change in the genetic composition of a population over time. • When scientists study populations, they also study the factors that cause the number of individuals to increase or decrease, Population Ecology. • Populations are dynamic (constantly changing,. Figure 4.12, page 91. • Decrease in population size due to emigration and deaths • Increase in population size due to immigration and births

35. A Community • A community incorporates all of the populations of organisms within a given area. • Communities exist within an ecosystem. All of Earth’s ecosystem’s are incorporated in the biosphere.

36. Community Ecology The study of the following interactions that determine the survival of a species in a habitat... • Competition • Predation • Mutualism • Commensalism

37. Competition • Competition is the struggle of individuals to obtain a limiting resource. • Limiting resource: a resource a population can’t live without, and which occurs in quantities lower than the population would require to increase in size • When two species have the same realized niche and are under a given set of environmental conditions, one species will perform better and will drive the other species into extinction. • Taller wildflowers obtain more of the available sunlight, therefore dominant in farm field • Competitive Exclusion Principle: Two species competing for the same limiting resource can’t coexist.

38. Predation • Predation is the use of one species as a resource by another species. • Who might be a predator? • Organisms of all sizes may be predators.

39. Categories of Predators • True Predators • Typically kill their prey • Consume most of what they kill • Lions °< Gazelles • Herbivores • Consume plants (prey) • Typically eat a small fraction of prey without killing it • Parasites • Live on or in organism (host) they consume • Tapeworms in the intestine • Pathogens: parasites that cause disease in their host • Viruses, bacteria • Parasitoids • Organisms that lay eggs inside other organisms • When eggs hatch, larvae consume the host from inside out, leads to death of host • Certain wasp, fly species

40. Mutualism • Mutualism benefits two interacting species by increasing both species’ chances of survival and reproduction. • Example: • Plants and their pollinators (birds, bats, insects) • Pollinator: A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization • Plants depend on pollinators for their reproduction • Pollinators depend on plant for food

41. Commensalism • A type of relationship in which one species benefits but the other is neither harmed nor helped • Examples: • Birds using trees as perches • Fish using coral reefs as places to hide from predators

42. A Symbiotic Relationship • A symbiotic relationship is the relationship of two species that live in close association with eachother • Commensalism • Mutualism • Parasitism

43. Review • Table 4.2, page 99 • Competition negative effect on both of the competing species because competing for limiting resource • Predation positive effect on predator, negative effect on prey • Mutualism positive effect on both interacting • Commensalism no effect on one species, positive on the other species • These interactions can affect the abundance and distribution of species in communities. • In most cases a given species has an effect on a small number of other species, not on the community. However, sometimes…

44. Keystone Species • One species may be more important and vital to the health of a community. • Exist in low numbers • May be predators, prey, mutualistic species, or may provide an essential service • In class: Read p. 100, Paragraph 2

45. Homework • Read pages 91, 92, 97-100 • Answer Gauge Your Progress, page 100 • What is it about the beaver that makes it an example of an ecosystem engineer?

46. Ecosystem Engineers • An ecosystem engineer: A keystone species that creates or maintains habitat for other species. • Example: • Beavers have a critical role in the forest community. • Build dams that convert narrow streams into large ponds • This creates a new habitat for pond adapted plants and animals • Ponds flood forest causing trees to die, which creates a habitat for animals that rely on dead trees • Several species of woodpeckers and ducks make their nests in cavities of dead trees

47. Change that occurs in communities • Ecological Succession • Replacement of one group of species by another group of species over time • What factors determine the number of species in a community? • Read pages 102-103

48. Patterns of Species Richness • Species are not distributed evenly on Earth. • Species are organized into biomes by global climate patterns and into communities whose composition changes regularly as species interact. • The number and types of species present within a given region are determined by… • Colonization of the area by new species • Formation of new and distinct species due to evolution • Losses from the area by extinction • Importance of these 3 basic processes varies by region but is influenced by latitude, time, habitat size, and distance from other communities

49. In-Class Reading • Working Toward Sustainability • Bringing back the Black-Footed Ferret, page 103