Chapter 14 Lecture Outline See PowerPoint Image Slides

Slides:



Advertisements
Similar presentations
KEY CONCEPT Evolution occurs in patterns.
Advertisements

Macroevolution: Evolution of a New Species
2/1/ 2011 Warm up  Summary of Darwin’s Theory 1._______________________differ. 2. competition for _______________ 3. best _________to environment survive.
Chapter 16: Evolution of Populations
Evolution Chapter 16.
Evolution of Populations
THE ORIGIN OF SPECIES CHAPTER 24.
Examine how life continues to evolve within a changing environment
CHAPTER 14 The Origin of Species
1 The Origin of Species Chapter Outline The Nature of Species Pre and Postzygotic Isolating Mechanisms Geography of Speciation Hawaiian Drosophila.
VOCABULARY Jessica Gómez. biogeography the study of the geographical distribution of living organisms and fossils on Earth homologous structure.
Chapter 24 Notes The Origin of Species. There is more to evolution than just explaining how adaptations evolve in a population. Evolution must also explain.
Speciation, Reproductive Isolation, and Patterns of Evolution AP Biology Evolution IV.
Chapter 24 The Origin of Species. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Speciation = origin of new species.
Chapter 24 ~ The Origin of Species
How Does Evolution Work? Individual organisms cannot evolve. Populations of a particular species evolve. Natural selection acts on the range of phenotypes.
15.1: New Species Evolve Vocabulary Objectives:
MECHANISMS OF EVOLUTION
Evolution notes part 2 Quarter 3 Week 9 Section 15.2 Summary– pages How can a population’s genes change over time? Populations, not individuals,
1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. PowerPoint to accompany CONCEPTS IN BIOLOGY TWELFTH EDITION.
Chapter 18 Speciation. What is a Species? The morphological species concept expresses the following: – Species, in its simplest interpretation means “kind”
Chapter 24 ~Macroevolution Origin of Species. What is a species? A population whose members have the potential to interbreed and produce viable, fertile.
Beyond Darwin 16.3 and some 17 Notes Can an individual evolve? Is evolution the survival of the fittest? Is evolution predictable?
Chapter 19 Changes in Species. Speciation Q: When are two populations new species? A: When populations no longer interbreed they are thought to be separate.
The Origin of Species Speciation. Speciation is the process by which one species splits into two or more species Speciation explains the features shared.
Copyright © 2009 Pearson Education, Inc.  A species can be defined as a group of organisms whose members can breed and produce fertile offspring, but.
Chapter 14 The Origin of Species.
Outstanding Origin of Species Ch 24. Vocabulary  1. Macroevolution – origin of new taxonomic groups (new species, genera, families etc)  2. Speciation.
LECTURE 8: Macroevolution. What is microevolution? –Evolution on a small scale –Change in allele frequencies from one generation to the next –A process.
Part 2 Evolution Notes. Natural Selection and Macroevolution Natural Selection shapes a population, making it adapted to its current environment. This.
Mechanisms of Evolution. I. Natural Selection & Charles Darwin  Charles Darwin ( ) an English scientist considered the founder of the evolutionary.
EVOLUTION Chapter 11.
Chapter 24 The Origin of Species. Question? u What is a species? u Comment - Evolution theory must also explain how species originate. u Darwin’s “Mystery.
Chapter 15 Evolution Natural Selection  Individuals in a population show variations.  Variations can be inherited.  Organisms have more offspring.
Evolution Evolution – change in inherited characteristics/traits in a population over several generations All organisms descend from a common ancestor.
Ch. 16: Evolution of Populations
Origins of Biological Diversity Chapter 15: pp
Evolution of Populations. How Common Is Genetic Variation? Many genes have at least two forms, or alleles. Many genes have at least two forms, or alleles.
MECHANISMS OF EVOLUTION. POPULATIONS, NOT INDIVIDUALS, EVOLVE An organism cannot change its phenotype. A phenotype can become more predominant in a population,
Mechanisms of Population Evolution
EVOLUTION Darwin’s theory of evolution by natural selection – On the Origin of Species – Organisms produce more offspring than can survive (Malthus)
Other Causes of Variation
Evolution Pre-AP Biology. Charles Darwin Known as the Father of Evolution Known as the Father of Evolution Wrote book On the Origin of Species Wrote book.
Mechanisms of Evolution
Objective: Speciation Do Now: Why is this population of horses considered to be the same species?
What is a Species? Biological species = A population or group of populations whose members have the potential to interbreed with one another in nature.
Population Genetics Chapter 16 & 17.
Evolution Notes. Charles Darwin –"On the origin of Species"
INTRODUCTION TO EVOLUTION An Overview of Chapters 16 & 17.
The Theory of Evolution.  Darwin developed the first theory on evolution, which is the basis for modern evolutionary theory ◦ Darwin spent 5 years sailing.
11.1 Genetic Variation Within Population KEY CONCEPT A population shares a common gene pool.
Macroevolution and the Definition of Species. Overview: That “Mystery of Mysteries” In the Galápagos Islands Darwin discovered plants and animals found.
Chapter 24 The Origin of Species. Speciation – The process whereby members of one species become another species – A species can evolve through time without.
Ch.24 ~ The Origin of Species “That mystery of mysteries – the first appearance of new beings on this Earth.”
Speciation. What is a species? Biological species concept – a population or group of populations whose members have the potential to interbreed in nature.
Objective: Speciation Do Now: Why is this population of horses considered to be the same species?
What is a Species? Biological species = A population or group of populations whose members have the potential to interbreed with one another in nature.
The Theory of Evolution
CHAPTER 24 The Origin of Species.
15-2 Mechanisms of Evolution
Speciation Chapter 14 March 2014.
The Origin of Species Chapter 24.
TO DO How Scientists Know About Punctuated Equilibrium.
Chapter 14 Lecture Outline
The Origins of New Species
Chapter 24 The Origin of Species.
Evolution and Speciation
EVOLUTION VOCABULARY.
Chapter 24 The Origin of Species
Presentation transcript:

Chapter 14 Lecture Outline See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes.

Evolutionary Patterns at the Species Level Microevolution vs. macroevolution Microevolution involves minor differences in allele frequency between populations of the same species. Macroevolution involves major differences that have occurred over long periods that result in the formation of new species. A is a group of organisms whose memspeciesbers have the potential to interbreed naturally and produce fertile offspring. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Determining if Two Populations Belong to the Same Species Using Gene Flow Gene flow is the movement of genes. From one generation to the next as a result of reproduction From one region to the next as a result of migration If two or more populations exhibit gene flow, Then they are considered the same species Horses and donkeys can interbreed, but do not experience gene flow. Their offspring, mules, are sterile. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Hybrid Sterility Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Akodon dolores and Akodon molinae Determining if Two Populations Belong to the Same Species Using Genetic Similarity Organisms belonging to the same species have a high degree of genetic similarity. Similarities in DNA sequences between individuals of two populations Suggest that gene flow has occurred recently between those populations Akodon dolores and Akodon molinae Presumed to be two different species of field mice Genetic analysis indicated that they were two populations of the same species, living in different geographical regions. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

How New Species Originate Speciation is the process of generating new species. Speciation has occurred continuously over the history of life on earth. The fossil record shows that huge numbers of new species have originated. Most of these have gone extinct. There are two main mechanisms of speciation. Geographic isolation Polyploidy Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Speciation by Geographic Isolation Occurs when a portion of a population becomes totally isolated from the rest If it is followed by genetic divergence Changes in allele frequencies Then reproductive isolation can result. The isolated population becomes a new species. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Geographically Isolated Populations Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Mechanisms of Geographic Isolation Colonization of a distant area A few individuals emigrate and establish a population far from their original home. The distance prohibits gene flow with the original population; the new population becomes reproductively isolated. Appearance of a geographic barrier Uplifting of mountains, rerouting of rivers or formation of deserts can subdivide a population. This barrier prohibits gene flow between the divided subpopulations; they can become reproductively isolated. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Mechanisms of Geographic Isolation Extinction of intermediate populations Occurs when a population that exists between other populations dies out Eliminates gene flow between the remaining distant populations The other populations can become reproductively isolated. Speciation will only happen if the genetic changes accumulated during the period of reproductive isolation generates two populations that can no longer interbreed and make fertile offspring. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Genetic Diversity and Reproductive Isolation are Necessary for Speciation Environmental pressures and natural selection play an important role in speciation. After a geographical separation, the two subpopulations will likely experience different environmental conditions. Different phenotypes will be selected for in each subpopulation. Over time, genetic differences that accumulate may result in structural, physiological and behavioral differences. These differences may prohibit interbreeding, thus resulting in speciation. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Speciation without Geographic Barriers Any process that leads to reproductive isolation can lead to speciation. May not necessarily require geographic isolation Breeding or flowering at different times of year Differences in genetically determined courtship and mating behaviors Genetically determined incompatibility of pollen from one species and flowers of another Polyploidy is the primary mechanism of speciation in the absence of geographical isolation. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Polyploidy A condition of having multiple sets of chromosomes. More than haploid or diploid Can result from abnormal events in mitosis or meiosis Chromosomes do not separate properly. Cannot mate with its original population Can self-fertilize and generate a new species Can result from the mating of two different species The hybrid ends up with a novel number of chromosomes. Cannot mate with either of the parent populations Cotton, potato, sugarcane, broccoli, wheat, etc. are all species that resulted from polyploidy. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Speciation without Geographic Isolation Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Maintaining Reproductive Isolation Between Species New species stay reproductively isolated from other species due to mechanisms that prevent mating between species. Reproductively isolating mechanisms Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Reproductively Isolating Mechanisms Ecological isolating mechanisms Two populations don’t interbreed because they occupy different niches. Seasonal isolating mechanisms Two populations don’t interbreed because they mate at different times of year. Behavioral isolating mechanisms Two populations don’t interbreed because they have different courtship and mating behaviors. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Reproductively Isolating Mechanisms Mechanical isolating mechanisms Two populations don’t interbreed because they have incompatible genitalia. Biochemical isolating mechanisms Two populations don’t interbreed because their gametes are chemically incompatible. Hybrid infertility/inviability Two populations that can interbreed, but their offspring are sterile or die before reproductive maturity. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Evolutionary Patterns Above the Species Level The development of new species is the smallest irreversible unit of evolution. After a speciation event, the new species continues to diverge from the original species. Several different evolutionary patterns follow speciation. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Divergent Evolution An evolutionary pattern in which individual speciation events cause successive branches in the evolution in a group of organisms. The evolution of horses. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Extinction The loss of a species. Most species that have ever existed are now extinct. Ever-changing environments leads to the generation of new species and the elimination of others. Divergence is accompanied by a great deal of extinction. This is the basic pattern of evolution. Other special patterns also exist. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Adaptive Radiation A special evolutionary pattern Involves a rapid increase in the number of kinds of closely related species A kind of evolutionary explosion of new species in a short amount of time Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Adaptive Radiation Thought to occur because A particular organism invades a previously unexploited environment. Animals moving to land Galapagos finches A particular type of organism evolves a new set of characteristics that allows it to displace previously successful organisms. Reptiles replacing amphibians Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Adaptive Radiation in the Galapagos Finches Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Adaptive Radiation in Terrestrial Vertebrates Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Convergent Evolution A special evolutionary pattern in which similar characteristics develop in unrelated groups of organisms The characteristics serve a similar purpose in the particular environment, but have very different ancestors. Spines in desert plants Eating while flying in bats, dragonflies and swallows Body shape of whales, sharks and tuna Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Convergent Evolution Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Homologous and Analogous Structures Determining if a characteristic that is similar in two different species is a result of convergent or common ancestry is important. Homologous structures Have different appearances and functions that arose from a common ancestor Result from divergent evolution Analogous structures Have similar structures and functions but arose from different ancestors Result from convergent evolution Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Maintaining Traits through Time Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Rates of Evolution Vary greatly When the environment changes rapidly From thousands to millions of years When the environment changes rapidly Organisms change rapidly as a result of natural selection. High rate of speciation High rate of extinction When the environment is stable Organisms change very little. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Theories About the Rate of Evolution Gradualism The fossil record shows gradual changes in physical features of organisms over time. Darwin’s view of evolution by natural selection implied gradualism. Punctuated equilibrium The fossil record also shows long periods of stasis. Argues that evolution happens in spurts of change, followed by long periods of equilibrium Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Gradualism vs. Punctuated Equilibrium Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

The Tentative Nature of the Evolutionary History of Organisms Tracking the evolutionary history of any given organism is difficult because most ancestral forms are now extinct. Fossils are helpful, but the fossil record is incomplete and provides limited amount of information about each specimen. The likelihood of fossilization is low. Only certain types of organisms can be fossilized. Evolutionary biologists use the information that they have to build evolutionary diagrams for groups of organisms. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

An Evolutionary Diagram Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Where are we on the tree? Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Human Evolution Our understanding of human evolution is based mainly on information from the fossil record. Humans are mammals, primates, specifically anthropoids. Hominins are humans and their human-like ancestors. Hominids refers to hominins and African great apes. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

The Course of Human Evolution Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

An Overview of Human Evolution Early primates were adapted to living in forests. As the climate became drier, grasslands replaced forests. Early hominins (Australopithecus) were adapted to living in grasslands. Stood upright to allow for More rapid movement over long distances Ability to see over longer distances Freed arms for using tools, etc. Later hominins (Homo) had larger brains and used tools. Had larger brains and bodies Able to use tools for a more diverse diet Believed to have evolved at least 2.2 to 2.5 million years ago Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

The Origin of Homo Sapiens — Two Points of View Out-of-Africa hypothesis Modern humans originated in Africa from other hominin species. Migrated to Asia and Europe and displaced other hominin species that had colonized those areas earlier. Multiregional hypothesis Homo erectus migrated and then evolved into H. sapiens. Various subgroups of H. erectus existed throughout Africa, Asia and Europe and interbred to give rise to the races we know today. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.