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Ecology-Macroevolution
Macroevolution refers to large-scale evolutionary changes that occur over long periods of time and result in new taxonomic groups. It encompasses trends like the origin of mammals and the diversification of flowering plants. Speciation, the origin of new species, can occur through anagenesis, where a population accumulates traits to become a new species, or cladogenesis, where branching evolution creates a new species from an ancestral line. Speciation is driven by the emergence of reproductive barriers between populations, either before or after zygote formation.
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Ecology-Macroevolution
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- 2. Origin of Variation MACROEVOLUTION I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric Sympatric 4. Speciation to Macroevolution Macroevolution Macroevolution is the origin of new taxonomic groups, as opposed to microevolution, which is genetic variation between generations within a species. Macroevolution encompasses the grandest trends and transformations in evolution, such as the origin of mammals and the radiation of flowering plants.
- 3. Origin of Variation MACROEVOLUTION I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric Sympatric 4. Speciation to Macroevolution Macroevolution Large Scale Evolutionary Changes That Take Place Over Long Periods of Time
- 4. Origin of Variation SPECIATION I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric Sympatric 4. Speciation to Macroevolution Macroevolution process by which a new species originates involves the creation of a population of organisms that are novel enough to be classified in their own group 1. Anagenesis 2. Cladogenesis
- 5. Origin of Variation SPECIATION I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric Sympatric 4. Speciation to Macroevolution Macroevolution Anagenesis is the accumulation of heritable traits in a population, that transforms that population into a new species. Cladogenesis is branching evolution, in which a new species arises as a branch of from the evolutionary tree. The original species still exists. This process is the source of biological diversity.
- 6. Origin of Variation SPECIATION I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution
- 7. Origin of Variation PREZYGOTIC& POSTZYGOTIC I. Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution Prezygotic barriers prevent mating or egg fertilization if members of different species try to mate. 1. Habitat isolation 2. Behavioral isolation 3. Temporal isolation 4. Mechanical isolation 5. Gametic isolation
- 8. Origin of Variation PREZYGOTIC I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution habitat isolation (or ecological isolation) – isolation by differences in habitat occupied at the time of mating examples: garter snakes flycatchers lions and tigers
- 9. Origin of Variation PREZYGOTIC I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution temporal isolation – isolation by differences in timing of mating; examples: mating season in some skunks flowering time in some plants mating time in some fruit flies mating dates in some frogs
- 10. Origin of Variation PREZYGOTIC I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution behavioral isolation – differences in behavior that cause reproductive isolation examples: mating calls courtship patterns
- 11. Origin of Variation PREZYGOTIC I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution mechanical isolation – differences in physical structure make mating impossible example: dragonflies may attempt interspecies mating, but the physical structure of their genitalia prevents successful mating
- 12. Origin of Variation PREZYGOTIC I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution gametic isolation – mating occurs, but the sperm and egg can not fuse examples: sperm cannot penetrate the egg of the different species, such as between sea urchins species in plants, often pollen grains do not get the proper signal to germinate when on a stigma of a different species
- 13. Origin of Variation POSTZYGOTIC I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution hybrid inviability -the most common type of postzygotic barrier -zygote formed from the mating of two species does not develop normally -the embryo is aborted, or if development is completed the offspring is very frail example: cross between bullfrog and leopard frog
- 14. Origin of Variation POSTZYGOTIC I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution hybrid sterility – a zygote of a hybrid proceeds through normal development, but is reproductively sterile sometimes due to other barriers such as behavioral isolation most often due to Example: donkey + horse = mule (sterile hybrid)
- 15. Origin of Variation POSTZYGOTIC I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution hybrid breakdown – a zygote of a hybrid proceeds through normal development, and the interspecific hybrid reproduces, but the F2 generation and beyond have problems with reproduction Example: crosses between some rice strains
- 16. Origin of Variation I.Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution
- 17. Origin of Variation PROCESSESOF SPECIATION I. Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution speciation (the evolution of new species) has two general forms, anagenic and cladogenic
- 18. Origin of Variation MODESOF SPECIATION I. Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution allopatric speciation – one population becomes geographically separated from the rest of the species sympatric speciation – a species achieves reproductive isolation and evolves in the same geographic location as its ancestral species
- 19. Origin of Variation MODESOF SPECIATION I. Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution
- 20. Origin of Variation MODESOF SPECIATION I. Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution Examples of Allopatric speciation: Allopatric speciation of squirrels in the Grand Canyon.
- 21. Origin of Variation MODELSOF MACROEVOLUTION I. Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution The Gradualism model suggests that change is gradual with the accumulation of unique morphological adaptation. The Punctuated Equilibrium model suggests that rapid change occurs, with a new species “erupting” from the ancestral lineage and then staying the same thereafter.
- 22. Origin of Variation MODELSOF MACROEVOLUTION I. Macroevolution II. Species 1. Speciation a. Anagenesis b. cladogenesis 2. Barriers a. prezygotic b. post zygote 3. Modes of Specification a. Allopatric b. Sympatric 4. Speciation to Macroevolution Macroevolution
Editor's Notes
- #2 We are done with microevolution, now I will be talking about macroevolution.
- #3 So in microevolution, studies are done in gene level, in macroevolution, it deals with the origin of new species.
- #4 It is a Large Scale Evolutionary Changes That Take Place Over Long Periods of Time. Variations caused by mutation, hene flow, genetic drift, and natural selection happened for 3.8 billions years is the scope of macroevolution.
- #5 Speciation is a term associated with macroevolution. It is process by which a new species originates. It involves the creation of a population of organisms that are novel enough to be classified in their own group. Species formation are classified into 2. Anagenesis and Cladogenesis
- #6 Anagenesis is the accumulation of heritable traits in a population, that transforms that population into a new species. And Cladogenesis is branching evolution, in which a new species arises as a branch of from the evolutionary tree. The original species still exists. This process is the source of biological diversity. To further differentiate the two, let us look the ilustration in the next slide.
- #7 We can we in letter a, anagenesis, that the bird gradually evolve and became a species whereas in letter b, cladogenesis, the bird was still there but there is a new species emerged from the original bird.
- #8 For a new species to form, there needs to be isolation of some members of a species as a separate population. Forms of isolation, that interfere with breeding include Both prezygotic and postzygotic. Prezygotic barriers prevent mating or egg fertilization if members of different species try to mate. There are 5 types of isolation. Habitat isolation, Behavioral isolation, Temporal isolation, Mechanical isolation, and Gametic isolation.
- #14 In cases where fertilization takes place, there are postzygotic barriers.
- #23 In letter a, the buttefly evoled gradually and the change was slow, consistent, and contanst. In letter b, change comes from spurts. There is period of very slow changes and one or few huge changes.