1. Chapter 8

2.  Early ideas:  Organisms were fixed  Earth was about 6000 years old  There was an organized progression from simple organisms to highly complex organisms – even applied to different races and gender in humans

4.  Amazing and complex diversity  1.8 mill species  350,000+ spp of beetle  Different regions have different species that fill similar niches  Doesn’t fit the idea of a single creation with specific roles for each species

5.  The idea that the Earth is old & species have gone extinct was fairly well documented by Darwin’s time  Evolution of life was a published idea  So what did he actually contribute?

6.  World exploration & mapping  Naturalists on board to collect species from around the world for Europe  Darwin was the naturalist on the Beagle that mapped the coast of South America in 1831, spending time around the Galapagos Islands  Took Lyell’s book that argued an ancient Earth with him and read it repeatedly

7.  Darwin arrived home 5 years later (1836)  He soon developed a mechanism for the process of evolution – natural selection  Felt he needed evidence to support this idea  Studied seed survival in large buckets of sea water  Studied orchids and pollination  Studied emotion in animals  Studied earthworm escape behavior  Studied species variation and artificially selected for various pigeon traits

9.  Alfred Russel Wallace developed the same ideas about natural selection while working in Malaysia (1856)  His collections didn’t make it back to England  He wrote of his ideas to Darwin when he learned he had similar ideas  Jointly presented their results at a conference

10.  1859 Darwin published his research results and documentation of  natural selection,  artificial selection and  sexual selection.  He also presented ideas on why island species can be so unique and different from the mainland species

11. A) a group of species that shares the same habitat. B) a group of individuals of the same species that lives in the same general location and has the same genotypes. C) a group of individuals of related species that lives in the same general location and has the potential to interbreed. D) a group of individuals of the same species that has the potential to interbreed. E) a group of individuals of the same species that lives in the same general location and has the potential to interbreed.

12. A) He dropped out of medical school. B) He spent 5 years traveling the world observing living organisms and collecting fossils. C) He was enthusiastic about unleashing his theory of natural selection on the world as soon as he thought of it. D) He and Alfred Russell Wallace independently came up with the theory of evolution by natural selection. E) He was under constant pressure from his father to make something of himself.

13. A) Some variation found in natural populations is heritable. B) Variation is found in all natural populations. C) All species have the ability to produce more offspring than can live and reproduce. D) Offspring tend to inherit characteristics acquired by their parents during their lifetimes. E) None of the above; all are important to his theory.

14.  Darwin explained how evolution could occur  Species are variable and some of that variability is inherited  Species populations grow and can exceed resources  Individuals compete for resources  Those better able to compete for resources will do so and be more successful at reproducing  When they reproduce they will pass on the traits that made them more competitive to their offspring  Over time, this will lead to these traits becoming more common

15. Variation in phenotype – can be physical features or physiological or developmental, etc.

16.  Environmental effects are not passed on  If you lose a hand in an accident – not passed on  If you exercise, you will not pass on greater muscle mass to your offspring  Genetic components to traits are passed on  Darwin didn’t read Mendel’s work, but he observed that offspring inherited traits from parents

17.  Traits that are better for survival and reproduction will result in more offspring on average  More organisms are born than can survive  Some will be more successful at surviving and reproducing  They will pass their traits to their offspring  The traits of less successful individuals will not be passed on (or less so) + will become less frequent or lost from the population.

18.  Variation for a trait  Heritability of that trait  Differential reproductive success based on that trait

19. Organisms can become better matched to their environment (higher fitness) through natural selection Traits that do this are called adaptations or adaptive traits Reproductive success is called an animal’s fitness. Fitness is measure relative to the fitness of other individuals in a breeding population – we measure an organism’s Relative Fitness

20.  Reproductive fitness is all that matters  Often taken to mean better survival, but without reproduction and passing on the traits, it doesn’t matter.

23.  Mutation  Error during replication  Chemical or radiation mutagens  Any change in the DNA sequence of a gene  We all carry at least one new mutation  Spontaneous abortions are actually quite common, often due to a deleterious mutation

24.  Movement of individuals into and out of a population can lead to changes in allele frequencies.  Island colonizers bring a subset of alleles from the main population

25.  Another process that can lead to a random change in allele frequency  More likely if the population is small  Environmental change can wipe out entire sets of alleles just by chance

28. A) disruptive selection. B) directional selection. C) genetic drift. D) migration. E) mutation.

29. A) the founder effect. B) the Hardy-Weinberg equilibrium. C) the genetic load. D) the bottleneck effect. E) the culling effect.

30. A) individual mosquitoes built up immunity to the pesticides after exposure. B) the pesticides caused mutations in the DNA of mosquitoes that conferred resistance phenotypes, and were passed on to subsequent generations. C) populations had to develop tolerance in order to survive. D) some individuals were resistant to the pesticides before they were used, and those mosquitoes were more likely to survive and reproduce. E) these populations were outside the range of the original pesticide application.

35.  Specialized form of natural selection  Two types  Competition for mates among individuals of the same sex; victor has differential reproductive success.  Choice of one gender on the other based on display and or behavior; one sex selects for favored traits in the other.

37. Bower birds

38. A) survival matters less to natural selection than reproductive success does. B) it is impossible to determine the fittest individuals in nature. C) reproductive success on its own does not necessarily guarantee evolution. D) natural variation in a population is generally too great to be influenced by differential survival. E) fitness has little to do with natural selection.

39. A) Running in place is an important measure of optimal running speed, which is a correlate of survival and reproduction. B) As individuals change to better fit their environment, their environment changes as well, subjecting the individuals to continually changing selective pressures. C) As species change to better fit their environment, their environment changes as well, subjecting the species to continually changing selective pressures. D) As individuals evolve through natural selection, they tend to move to new places that are very similar to the places in which they evolved. E) As individuals evolve through natural selection, they show a greater tendency to remain in the same place.

40.  Directional – pushing a more extreme trait  Stabilizing – increasing the average trait  Disruptive – increasing the two extreme traits

41.  The fossil record  Biogeography  Comparative anatomy and embryology  Molecular biology  Laboratory and field studies

42.  Fossils are formed by various ways  Usually only hard structures are preserved  Only when conditions are good such as in tar pits, tree sap, mud bottoms of lakes or shoreline,  Decomposers have to be kept out or limited

43.  Hundreds of millions of years to document  Evolution of soft bodied animals is spotty  May not have full skeleton  May only have shell so don’t know the organs  May only have one

46.  Snails, turtles, elephants, transition to vertebrate land forms, fish, dinosaurs, birds, termites, the list goes on.

48. A) genetic differences B) genetic similarities C) convergences D) DNA bases E) homologous structures

49. A) molars in bats that consume a completely liquid diet B) eye sockets in eyeless cave-dwelling fish C) pelvic bones in whales D) All of the above are examples of vestigial structures.

50. A) differences among vertebrate forelimbs suggest that they evolved independently. B) similarities among vertebrate forelimbs suggest that they evolved from a common ancestor. C) the anatomy of the vertebrate forelimb is not currently under natural selection. D) similarities among vertebrate forelimbs suggest that they have evolved convergently. E) such homologies do not exist in other areas of the vertebrate skeleton.