Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the...
-
Upload
clyde-manning -
Category
Documents
-
view
229 -
download
0
Transcript of Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the...
![Page 1: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/1.jpg)
Chapter 24The Origin of Species
![Page 2: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/2.jpg)
Macroevolution
• the origin of new taxonomic groups
Speciation: the origin of new species
![Page 3: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/3.jpg)
• Anagenesis: accumulation of changes within a population, transforming that population into a new species
• Cladogenesis: branching evolution, whereby a new species arises from a parent species
![Page 4: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/4.jpg)
![Page 5: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/5.jpg)
Biological Species Concept
• Defines a species as a population or group of populations that have the potential to breed with each other in the wild and produce viable, fertile offspring
![Page 6: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/6.jpg)
What are some of the limitations of the biological species concept?
![Page 7: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/7.jpg)
Ecological Species Concept
• Defines a species in terms of its ecological niche
![Page 8: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/8.jpg)
Morphological Species Concept
• Characterizes each species in terms of its unique set of structural features
![Page 9: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/9.jpg)
Genealogical Species Concept
• Defines species in terms of its unique genetic history
![Page 10: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/10.jpg)
Pluralistic Species Concept
• The factors that are most important for the cohesion of a species vary
![Page 11: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/11.jpg)
Reproductive Isolation
• Factors that prevent interbreeding
Note: These are factors that intrinsic to the species itself and does not include geographic isolation
![Page 12: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/12.jpg)
Reproductive barriers can either be prezygotic or postzygotic
• Zygote: fertilized egg
![Page 13: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/13.jpg)
Prezygotic barriers
• Impede mating between species or hinder fertilization of ova if two members attempt to mate
![Page 14: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/14.jpg)
Prezygotic Barriers
• Habitat isolation – if two species live within the same area but different habitats
• Behavioral Isolation – often depends upon courtship rituals
![Page 15: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/15.jpg)
Prezygotic Barriers, cont’d
• Temporal Isolation: if two species mate during different times of the day, different seasons, or different years
• Mechanical isolation: two species are not anatomically compatible
• Gametic isolation: two gametes meet but fail to fertilize
![Page 16: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/16.jpg)
Postzygotic Barriers
• Reduced hybrid viability: hybrids are not very healthy, don’t live to maturity
• Reduced hybrid fertility: hybrids are sterile• Hybrid breakdown: first-generation offspring
are fertile and viable but when these offspring mate with either each other or parent species, offspring are feeble or sterile
![Page 17: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/17.jpg)
Modes of Speciation
• Based on how gene flow is interrupted
![Page 18: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/18.jpg)
Allopatric Speciation
• Speciation takes place in populations with two geographically separate ranges
![Page 19: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/19.jpg)
![Page 20: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/20.jpg)
Sympatric Speciation
• Speciation takes place in geographically overlapping areas
• How might these barriers arise?
![Page 21: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/21.jpg)
![Page 22: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/22.jpg)
Punctuated Equilibrium Model
• Argues that species diverge in spurts of relatively rapid change instead of slowly and gradually
![Page 23: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/23.jpg)
Exaptations
• Structures that evolve in one context but becomes co-opted for another function– Ex: feathers in birds
![Page 24: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/24.jpg)
Evo-devo
• The link between evolutionary biology and the study of how organisms develop is called “evo-devo”
• Allows us to understand how small changes in the genome can lead to dramatic changes in an organism
![Page 25: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/25.jpg)
Toolkit Genes
• Subset of genes used to pattern the body• Proteins encoded by these genes control the
formation, design, and patterning of most major features of animal design and diversity
![Page 26: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/26.jpg)
Homeotic Genes
• Control placement and spatial organization of body parts
![Page 27: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/27.jpg)
Hox genes
![Page 28: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/28.jpg)
Ultrabithorax mutation
![Page 29: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/29.jpg)
![Page 30: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/30.jpg)
Eyeless
• First discovered in Drosophila. Humans have a homologous protein called Pax6.
• Homeotic gene. Responsible for turning on other genes (transcription factor)
• Loss of eyeless leads to a loss of eyes. (Flies without eyes)
![Page 31: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/31.jpg)
If you turn on eyeless in another part of the fly -
Ectopic eyes!
Halder et al, 1995
![Page 32: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/32.jpg)
Paedomorphosis
• When the adult species retains structures that were juvenile structures in an ancestral species
Ex: axolotl
![Page 33: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/33.jpg)
Heterochrony
• Evolutionary change in the rate or timing of developmental events
![Page 34: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/34.jpg)
Allometric Growth
• The relative growth rates of different parts during development
![Page 35: Chapter 24 The Origin of Species. Macroevolution the origin of new taxonomic groups Speciation: the origin of new species.](https://reader035.fdocuments.in/reader035/viewer/2022062221/56649ed25503460f94be109a/html5/thumbnails/35.jpg)
Allometric Growth Example – human and chimpanzee skulls