EVOLUTION REVIEW Chapter 16 Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing © 2006

Differences among individuals within a species Change in a population over time evolution Differences among individuals within a species Natural variation

Homologous structures Structures that develop from the same embryonic tissues, but have different mature forms Homologous structures Organ with little or no function Vestigial organ

Inherited characteristic that increases and organism’s chances Ability of an organism to survive and reproduce in a specific environment fitness Inherited characteristic that increases and organism’s chances for survival adaptation

Preserved remains of an ancient organism fossil Islands that Darwin visited on his voyage on the Beagle that started him thinking about how organisms change over time Galapagos

Descent with Modifications Concept that each living species has descended with changes from other species over time Descent with Modifications Idea that organisms that are best suited to their environment will survive and reproduce Survival of the Fittest

GIVE AN EXAMPLE OF A PHYSICAL ADAPTATION Webbed feet, horns, antlers, claws, feathers, wings, camouflage, . . . . there are a million GIVE AN EXAMPLE OF A BEHAVIORAL ADAPTATION Nocturnal (coming out at night); Flying south for the winter, living in herds, “wagon train” defense; burrowing; hibernation

Process by which unrelated organisms independently evolve When humans select and breed animals with certain useful traits from the natural variation in the population Artificial selection Process by which unrelated organisms independently evolve similarities when adapting to similar environments Convergent evolution

“On the Origin of Species” Book published by Charles Darwin in which he proposed a mechanism and provided evidence for his Theory of Evolution “On the Origin of Species” Process by which related organisms evolve differences when they are isolated in different environments Divergent evolution

The bones in the diagrams below are examples of ________________ Homologous structures http://www.angelfire.com/ab7/evolution12/evolutionclues.html

Alfred Wallace French naturalist who hypothesized Naturalist who gave Darwin incentive to publish his ideas about evolution by writing an essay that described similar ideas. Alfred Wallace French naturalist who hypothesized that organisms acquire traits during their lifetime through use or disuse which can be passed on to offspring Jean-Baptiste Lamarck

James Hutton & Charles Lyell 2 geologists who recognized that Earth is many millions of years old and that processes that changed it still operate today James Hutton & Charles Lyell English economist who reasoned that if the human population kept growing unchecked, there would be insufficient food and space for everyone Thomas Malthus

Explain what was incorrect about Lamarck’s Inheritance of Acquired Traits hypothesis Genes determine which traits are passed on; unless genes are changed the acquired trait will only show in the original organism Explain what was correct about Lamarck’s Inheritance of Acquired Traits hypothesis First theory about evolution; Organisms do change and adapt to their environments

Name 3 kinds of evidence that supports Darwin’s THEORY OF EVOLUTION Fossils Geographic distribution Homologous structures Vestigial organs Embryology DNA Pseudogenes Artificial selection Can see natural selection work antibiotic resistance, new diseases,

Natural selection is the same as ______________ The idea that all species, living and extinct, were derived from a common ancestor Common descent Natural selection is the same as ______________ Survival of the fittest

The practice of breeding dogs to produce offspring with specific Measuring lima beans and finding beans come in different sizes is an example of ____________ Natural variation The practice of breeding dogs to produce offspring with specific traits is an example of _________________ Artificial selection

A human’s appendix and a skink’s legs are examples of _______________ Vestigial organs How would Lamarck explain these giraffes with longer necks? They grew longer with use Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing © 2006

How would Darwin explain these giraffes with longer necks? Populations naturally have individuals with different sizes of necks (natural variation) The ones with longer necks are better able to get food, survive, and pass on their longer neck genes. Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing © 2006

How would Darwin explain the evolution of this giraffe population towards longer necks? Longer necked giraffes can better compete for food and survive to reproduce, passing on their long necked genes. Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing © 2006

How would Lamarck explain the evolution of this giraffe population towards longer necks? The long-necked trait acquired by stretching can be passed onto offspring and those organisms will be better able to survive. Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing © 2006

Common descent The diagrams at the right show evidence of ____________ http://www.angelfire.com/ab7/evolution12/evolutionclues.html The diagrams at the right show evidence of ____________ A. natural selection B. natural variation C. common descent D. artificial selection Common descent

According to this diagram, modern whales have a vestigial pelvis and femur. What does this suggest about ancestors of modern whales? Ancestors of modern whales had legs and walked on land Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing © 2006

The adaptations in species of finches that Darwin observed on the Galάpagos Islands were different shaped _____________ beaks Why did Darwin first hesitate to publish his ideas about evolution? His findings challenged fundamental scientific beliefs at the time

A possible explanation for a set of observations or a possible answer to a scientific question Change in the DNA sequence of an organism due to mistake is replication or damage from radiation or chemicals hypothesis mutation

Whales and wolves share a common ancestor, but have evolved to look very different. This is an example of _____________ evolution. divergent What do we call genes that have lost their function due to mutations? pseudogenes

Whales and sharks are not closely related, but have evolved to have similar body shapes and fins because they live in similar environments. This is an example of _____________ evolution. convergent

Tell one piece of evidence that suggests human chromosome #2 evolved by joining 2 smaller ancestor chromosomes. Banding pattern matches It has telomeres in the middle instead of just at the ends. It has an extra inactive centromere instead of just one.

Whales and wolves share a common ancestor, but have evolved to look very different. This is an example of _____________ evolution. divergent What do we call genes that have lost their function due to mutations? pseudogenes

Give an example of homologous structures Human arm, bird wing, whale flipper Give an example of a pseudogene you learned about Vitamin C gene in primates, genes for “smell” in humans

A well supported, testable explanation of phenomena that have occurred in the natural world is called a ______________ Name the ship that Darwin spent 5 years on traveling around the world. theory H.M.S. Beagle

Who is the scientist that proposed the idea that forces have been changing the Earth and have been at work for millions of years? James Hutton Who is the scientist that proposed the idea of “Inheritance of Acquired Traits”? Jean-Baptiste Lamarck

Who is the scientist that proposed the idea that forces which have been changing the Earth are still at work? Charles Lyell Who realized that human populations were increasing and said eventually there would not be enough food and space for everyone? Thomas Malthus

Who is the scientist that proposed an idea about evolution which prompted Darwin to publish his theory? Alfred Wallace Fur, feathers, beaks, antlers, & claws are all examples of ____________ adaptations

Survival of the fittest; When lions prey on a herd of antelope, some antelope are killed and some escape. Which part of Darwin’s theory of evolution might be used to describe this situation? Survival of the fittest; Adaptations can be which of these? Physical behavioral geographical Physical or behavioral

Explain what was incorrect about Lamarck’s Inheritance of Acquired Traits hypothesis TRAITS ARE DETERMINED BY GENES; ACQUIRED TRAITS ARE NOT PASSED ON Explain what was correct about Lamarck’s Inheritance of Acquired Traits hypothesis LIVING THINGS CHANGE OVER TIME TO BEST FIT THEIR ENVIRONMENTS

Another name for divergent evolution is ________________ What Darwin called “survival of the fittest” _________________ Another name for “struggle for existance” is _______________ Adaptive radiation Natural selection competition

Of all the places he visited, the ______________ Islands influenced Darwin’s ideas about evolution the most. GALAPAGOS In addition to observing living organisms, Darwin studied the preserved remains of ancient organisms called _________________ fossils

D. Varied from island to island On the Galápagos Islands, Darwin observed that the characteristics of many animals and plants A. all looked alike B. were completely unrelated C. were acquired through use D. varied from island to island . D. Varied from island to island

C. Darwin didn’t know about DNA! Darwin’s concept of evolution was influenced by all of the following EXCEPT _________________ A. the work of Charles Lyell and James Hutton B. his collection of specimens and fossils C. his knowledge of the structure of DNA D. his voyage around the world E. Malthus’s ideas about populations and resources C. Darwin didn’t know about DNA!

All of these statements about the structure of human chromosome #2 provide evidence for evolution EXCEPT _______________________ A. Its banding pattern matches the pattern seen on two smaller chimp chromosomes B. It has telomeres in the center, as well as at the ends C. It carries a functional gene for making vitamin C D. It has an extra non-functional centromere C. Humans have a nonfunctional vitamin C making gene, and its not on chromosome #2

Give a summary of Darwin’s theory of evolution Natural variation in population provides basis for natural selection to act Overproduction of offspring forces competition for resources (struggle for survival) Organisms best suited to their environment will survive and reproduce; Other organisms die or leave fewer Offspring (survival of the fittest/natural selection) Species alive today have descended with modification from ancestral species that lived in the distant past All organisms are united into a single “tree of life” (common descent)

Traits controlled by two or more genes Polygenic trait Process by which related organisms evolve differences when they are isolated in different environments Divergent evolution OR Adaptive radiation

Measuring lima beans and finding beans come in different sizes is an example of ____________ Natural variation Process by which unrelated organisms independently evolve similarities when adapting to similar environments Convergent evolution

Genetic equilibrium A situation in which the allele frequencies in a population do NOT change and the population does NOT EVOLVE Genetic equilibrium Idea that allele frequency will remain constant unless one or more factors cause those frequencies to change Hardy-Weinberg Principle

Bell-shaped curve (OR normal distribution) Type of distribution curve shown by polygenic traits Bell-shaped curve (OR normal distribution) Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006

Stabilizing selection The effect of natural selection when individuals near the center of a normal curve of distribution have higher fitness than those at the extremes Stabilizing selection Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006

Directional selection The effect of natural selection when individuals at one end of the normal distribution curve have higher fitness than individuals in the middle or at the other end Directional selection Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006

The effect of natural selection when individuals at the extreme ends of the normal distribution curve have higher fitness than those near the center of the curve Disruptive selection Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006

Random mating NO mutations TELL THE CONDITIONS UNDER WHICH THE HARDY-WEINBERG PRINCIPLE HOLDS TRUE: Random mating LARGE population NO mutations NO movement IN OR OUT NO natural selection

There is NO EVOLUTION hypothesis If all the conditions of Hardy-Weinberg are met, what happens to the population? A possible explanation for a set of observations or a possible answer to a scientific question There is NO EVOLUTION hypothesis

Can all the conditions of Hardy-Weinberg ever be met? In rare populations over long periods of time they may be met (or nearly met) BUT MOST OF THE TIME NO WAY! You can have small & isolated populations (no moving in or out) BUT. . . there is always non-random mating, mutations, & natural selection. So there is ALMOST ALWAYS EVOLUTION HAPPENING !

Punctuated equilibrium Darwin believed in the idea that evolution happened slowly over a long period of time called __________ Pattern of evolution in which long Stable periods of little evolution interrupted by brief periods of rapid change gradualism Punctuated equilibrium

Punctuated equilibrium WHICH PATTERN IS IT? coevolution adaptive radiation divergent evolution punctuated equilibrium mass extinction Horse evolution shows long stable periods of little evolution interrupted by brief periods of rapid change Punctuated equilibrium Biology by Miller and Levine Pearson Publishing

Adaptive radiation WHICH PATTERN IS IT? coevolution adaptive radiation divergent evolution punctuated equilibrium mass extinction The Galápagos finches evolved through natural selection from a common ancestor into a wide variety of different looking species with different kinds of beaks Adaptive radiation

Mass extinction WHICH PATTERN IS IT? coevolution adaptive radiation divergent evolution punctuated equilibrium mass extinction At the end of the Cretaceous period an asteroid hit the Earth causing the loss of many species including the dinosaurs Mass extinction

Adaptive radiation (divergent evolution) http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T014608A.gif WHICH PATTERN IS IT? coevolution adaptive radiation divergent evolution punctuated equilibrium mass extinction The Galápagos finches evolved through natural selection from a common ancestor into a wide variety of different looking species with different kinds of beaks Adaptive radiation (divergent evolution)

coevolution WHICH PATTERN IS IT? coevolution adaptive radiation divergent evolution punctuated equilibrium mass extinction Hummingbirds have a beak just the right length to reach the nectar in a cardinal flower and as they feed their foreheads bump into the pollen structure. Cardinal flowers are red which hummingbirds can see, but bees can’t, and their pollen structure is at just the right height for the hummingbird to pick up pollen as it feeds. coevolution

Convergent evolution WHICH PATTERN IS IT? coevolution adaptive radiation divergent evolution punctuated equilibrium mass extinction Whales, sharks, and penguins all have streamlined bodies and fins/flipper for moving in water even though they belong in different animal groups (mammals, fish, and birds) Convergent evolution

Adaptive radiation OR divergent evolution WHICH PATTERN IS IT? coevolution adaptive radiation divergent evolution punctuated equilibrium mass extinction Beaver NORTH AMERICA Muskrat Capybara SOUTH AMERICA Coypu Beaver and Muskrat Beaver in North America and capybara in South America are closely related species living in very different environments that have evolved to look different over time. Adaptive radiation OR divergent evolution BIOLOGY by Miller and Levine Pearson Publishing

Adaptive radiation OR divergent evolution WHICH PATTERN IS IT? coevolution adaptive radiation divergent evolution punctuated equilibrium mass extinction The tortoises on the Galapagos islands share a common ancestor, but over time they have become adapted for obtaining food in different habitats on different islands by having different neck lengths Adaptive radiation OR divergent evolution

Stabilizing selection WHICH PATTERN of SELECTION IS IT? stabilizing disruptive directional Human babies born smaller than average are likely to be less healthy and less likely to survive. Larger than average babies are likely to have difficulty being born. The fitness of these larger or smaller weight babies is lower than average-sized babies so human babies tend to born of average size. Stabilizing selection

directional selection WHICH PATTERN of SELECTION IS IT? stabilizing disruptive directional Lighter colored peppered moths were more common in England prior to the Industrial revolution. As pollution increased, the darker colored moths were less likely to be eaten. Over time darker colored moths have become more abundant in the population. directional selection

disruptive selection WHICH PATTERN of SELECTION IS IT? stabilizing disruptive directional A population of birds lives in an area where plants with medium sized seeds are wiped out by a fungal infection. Birds with unusually large or small beaks would have higher fitness than those with medium sized beaks. Over time the population splits into two subgroups; one that eats small seeds and one that eats large seeds. disruptive selection

EVOLUTION IS STILL HAPPENING THE END. . . or is it? EVOLUTION IS STILL HAPPENING