1. Introduction to Biology
Week 4

2. Today… Please sign in Turn in homework Notes, Part III
Virtual Labs: Dino Dig and Classifying using Biotechnology
Homework

3. http://www.youtube.com/watch?v=faRlFsYmke Y

4. Chapter 14 Darwin and Evolution
14.1Darwin’s Theory of Evolution
Darwin- British man who was a ship’s naturalist (on the Beagle)who traveled the world gathering information on the natural sciences
Before Darwin people believed the Earth was only a few thousand years old and that species remained the same over time

6. Important people to the background of evolution:
Georges Cuvier- paleontologist (studies fossils) showed fossils of life forms had changed over time
Jean-Baptiste de Lamarck- biologist came up with the idea of inheritance of acquired characteristics (use and disuses of structures can result in change)
This idea is not currently supported

7. Lamark:

8. Charles Darwin- said living things share common characteristics because they have a common ancestry
Belief in natural selection
Alfred Russel Wallace- English naturalist who also came up with the idea of natural selection

9. Biogeography: the study of distribution of life-forms on Earth
Darwin’s conclusion
Based on collection of fossils- the species changed over time
Based on observations of geologic processes- the Earth is very old
Based on observations of animals (including finches, tortoises)- species could be modified by environmental influences
Speciation: formation of a new species
Adaptation: any characteristic that makes an organism suited to its environment.

10. Natural Selection- mechanism in which adaptations arise
Members of population must have heritable variations
More offspring are produced than the environment can support
Individuals who have favorable traits survive and reproduce more
Across generations, a larger proportion of the population possess the favorable traits (the population becomes adapted to the environment)

11. Variations are essential to the natural selection process
Organisms differ in fitness, the reproductive success relative to other members of the population
Artificial selection: breed animals for particular traits
Adaptations take many generations to evolve
Natural selection causes adaptive traits to be increasingly represented in each succeeding generation

12. :Darwin

13. 14.2 Evidence for Evolution Fossils Biogeographical
Transitional fossils- in-between species
Biogeographical
Distribution of organisms around the world

14. Anatomical
Vestigial structures- features that are fully developed in one group but reduced and nonfunctional in other similar groups
Homologous structures- similar structures explained by inheritance from a common ancestor
Analogous structures-structures that serve the same function but not the same ancestry
Embryological development
Molecular
DNA, ATP, amino acids

15. Homologous Analogous

16. Chicken
Pig
Human

17. Chapter 15 Evolution on a Small Scale
Evolution occurs within a population, not an individual (population- group of single species in the same area at the same time)
Microevolution- the small measurable evolutionary changes that occur within a population over generations

18. These conditions are rarely met, therefore populations do change
Hardy-Weinberg Principle: genotype frequencies will remain in effect if
No mutations occur
No gene flow
Random mating occurs
No genetic drift
No selection
These conditions are rarely met, therefore populations do change

19. 15.1 Microevolution Causes of microevolution Genetic mutations
Gene flow- movement of alleles among populations by migration of breeding individuals
Creates subspecies- different populations within the same species
Nonrandom mating- inbreeding, assertive mating (by those who share phenotypes), sexual selection (favors traits that help obtain a mate)

20. Genetic drift- change in allele frequencies due to chance
Small populations are susceptible
Bottleneck effect- a species subject to near extinction and only a few survivors pass on genotypes to the next generation
Founder effect- rare alleles occur in a population isolated from the other populations

21. Adaptations are not perfect
15.2 Natural Selection
Natural selection- process that results in adaptation of a population to the biotic and abiotic environments; the most fit individuals become more prevalent in the population
Types of selection:
Directional: extreme phenotype is favored
Stabilizing: intermediate phenotype is favored
Disruptive: two or more extreme phenotypes are favored over intermediate
Adaptations are not perfect

25. Chapter 16 Evolution on a Large Scale
16.1 Macroevolution
Large changes over a large period of time
Speciation: the splitting of one species into another
Species: interbreed, have a shared gene pool and is reproductively isolated from other species
Common ancestor: single ancestor for two or more different groups

26. Reproductive Barriers:
Prezygotic isolating mechanisms- prevent reproductive attempts
Habitat isolation
Temporal isolation
Behavioral isolation
Mechanical isolation
Gamete isolation

27. Postzygotic isolating mechanisms- prevent hybrid offspring if reproduction attempts are successful
Zygote mortality
Hybrid sterility
F2 fitness (hybrid offspring unable to reproduce)

28. Geologic time scale- breaks Earth’s history into divisible parts
16.2 The Fossil Record
Geologic time scale- breaks Earth’s history into divisible parts
Pace of speciation
Gradualistic model- each group continually and slowly changes
Punctuated equilibrium model- a period of no change is interrupted by a speciation
Most species exist a short time before dying out (going extinct)
Mass extinction- disappearance of a large number of species in a short period of time

30. Understanding the phylogeny- evolutionary history
16.3 Systematics
Understanding the phylogeny- evolutionary history
Taxonomy- branch of biology concerned with naming, identifying and classifying organisms
Levels of classification- species, genus, family, order, class, phylum, kingdom, domain
Phylogenetic tree-diagram that indicates common ancestors and lines of descent
Use a variety of data to construct

32. Linnaean classification does not always fit in with new information
Cladistics- using shared traits to trace evolutionary history then creating a tree called a cladogram
Linnaean classification does not always fit in with new information
Three domain system
Bacteria, Archaea, Eukarya

34. Evolution Concept Map

36. Natural Selection Review…
Natural Selection- mechanism in which adaptations arise
Individuals who have favorable traits survive and reproduce more
Across generations, a larger proportion of the population possess the favorable traits (the population becomes adapted to the environment)

37. Virtual Labs Please complete both labs in class today if possible…
Dino Dig
Classifying Using Biotechnology

38. Homework
Study for midterm