EVOLUTION REVIEW Chapter 15 & 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

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

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

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

Book published by Charles Darwin in which he proposed a mechanism Trait controlled by a single gene Single gene trait Book published by Charles Darwin in which he proposed a mechanism and provided evidence for his Theory of Evolution “On the Origin of Species”

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 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

Geographic distribution Homologous structures Embryology DNA Name 3 kinds of evidence that supports Darwin’s THEORY OF EVOLUTION Fossils Geographic distribution Homologous structures Embryology DNA

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

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

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) 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

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 change in a DNA sequence caused by a mistake in DNA replication or exposure to radiation or chemicals mutation Changes in the allele frequency in a small population that are due to random chance and don’t follow the laws of probability Genetic drift

All the genes, including all the different alleles, in a population Gene pool A situation in which the allele frequencies in a population do NOT change and the population does NOT EVOLVE Genetic equilibrium

A change in relative frequency of alleles in a population Trait controlled by two or more genes polygenic A change in relative frequency of alleles in a population evolution

A change in allele frequencies due to the migration of a small subgroup of a population to a new place Founder effect Idea that allele frequency will remain constant unless one or more factors cause those frequencies to change Hardy-Weinberg Principle

replication Copying DNA is called __________ Exchange of DNA between homologous chromosomes during PROPHASE I of MEISOIS Mixing up of maternal and paternal chromosomes in different combinations during ANAPHASE of MEIOSIS Crossing over SEGREGATION & INDEPENDENT ASSORTMENT

A trait controlled by a single gene with two alleles Single gene trait The number of times a certain allele occurs in a gene pool compared to the number of times other alleles for the same gene occur Relative frequency

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)

caused by mistakes in copying DNA caused by radiation Tell two sources of genetic variation in populations Mutations caused by mistakes in copying DNA caused by radiation or environmental chemicals Gene shuffling during meiosis crossing over independent assortment

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

independent assortment How does gene shuffling occur during meiosis? Crossing over & independent assortment What are some causes of mutations? Mistakes during DNA copying (replication) Environmental chemicals or radiation

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 !

THE END