Students -Turn in Video worksheet – make sure your name is on it -Galapagos forms in box – Meeting 6:30 -LL Mid point check (Ch 22 – 24) – Monday -HW Lab – due TOMORROW -Regular write-up with 6 sections -Pre-lab: HW info - written -Purpose/overview - written -Personal Acct: -Written procedure -Data -Discussion: -Each case’s questions…except Case IV -6 practice problems -Conclusion – written -Phones in bin….off or muted….please & thank you

Essential Questions LO 1.20 The student is able to analyze data related to questions of speciation and extinction throughout the Earth’s history. LO 1.21 The student is able to design a plan for collecting data to investigate the scientific claim that speciation and extinction have occurred throughout the Earth’s history. LO 1.23 The student is able to justify the selection of data that address questions related to reproductive isolation and speciation. LO 1.24 The student is able to describe speciation in an isolated population and connect it to change in gene frequency, change in environment, natural selection and/or genetic drift. LO 1.25 The student is able to describe a model that represents evolution within a population.

Chapter 24: The Origin of Species 1.What is a species? -A population whose members can interbreed in nature and produce viable, fertile offspring -aka….reproductive isolation 2.What kinds of barriers keep different species isolated so they cannot mate? -Figure Pre–zygotic barriers – before mating &/or zygote is formed -Post–zygotic barriers – after zygote is formed

Figure 24.4 Reproductive Barriers Prezygotic barriers impede mating or hinder fertilization if mating does occur Individuals of different species Mating attempt Habitat isolation Temporal isolation Behavioral isolation Mechanical isolation HABITAT ISOLATION TEMPORAL ISOLATIONBEHAVIORAL ISOLATION MECHANICAL ISOLATION (b) (a) (c) (d) (e) (f) (g)

Viable fertile offspring Reduce hybrid viability Reduce hybrid fertility Hybrid breakdown Fertilization Gametic isolation GAMETIC ISOLATION REDUCED HYBRID VIABILITY REDUCED HYBRID FERTILITY HYBRID BREAKDOWN (h) (i) (j) (k) (l) (m) Grolar bears – natural cross between grizzly & polar bears

Chapter 24: The Origin of Species 1.What is a species? 2.What kinds of barriers keep different species isolated so they cannot mate? 3.How are new species created? -Allopatric speciation -when a geographic barrier isolates a population blocks gene flow -ex. mountain range emerging, new river dividing a field, island -Sympatric speciation -intrinsic factors such as chromosomal changes (plants) or non-random mating alter gene flow

Figure 24.5 Two main modes of speciation (a) Allopatric speciation. A population forms a new species while geographically isolated from its parent population. (b) Sympatric speciation. A small population becomes a new species without geographic separation.

Chapter 24: The Origin of Species 1.What is a species? 2.What kinds of barriers keep different species isolated so they cannot mate? 3.How are new species created? -Allopatric speciation – -when a geographic barrier isolates a population blocks gene flow -ex. mountain range emerging, new river dividing a field, island -Adaptive radiation -evolution of many diversely adapted species from a common ancestor -Seen on islands – Darwin’s finches -Sympatric speciation -intrinsic factors such as chromosomal changes (plants) or non-random mating alter gene flow

Figure Adaptive radiation Dubautia laxa Dubautia waialealae KAUA'I 5.1 million years O'AHU 3.7 million years LANAI MOLOKA'I 1.3 million years MAUI HAWAI'I 0.4 million years Argyroxiphium sandwicense Dubautia scabra Dubautia linearis N

Chapter 24: The Origin of Species 1.What is a species? 2.What kinds of barriers keep different species isolated so they cannot mate? 3.How are new species created? -Allopatric speciation – -when a geographic barrier isolates a population blocks gene flow -ex. mountain range emerging, new river dividing a field, island -Adaptive radiation -evolution of many diversely adapted species from a common ancestor -Seen on islands – Darwin’s finches -Sympatric speciation -intrinsic factors such as chromosomal changes (plants) or non-random mating alter gene flow -ex. oats, cotton, tobacco, potatoes, wheat -Autopolyploidy -An individual has more than 2 chromosome sets derived from a single species from an error in meiosis

Figure 24.8 Sympatric speciation by autopolyploidy in plants 2n = 6 4n = 12 2n2n 4n4n Failure of cell division in a cell of a growing diploid plant after chromosome duplication gives rise to a tetraploid branch or other tissue. Gametes produced by flowers on this branch will be diploid. Offspring with tetraploid karyotypes may be viable and fertile—a new biological species.

Chapter 24: The Origin of Species 1.What is a species? 2.What kinds of barriers keep different species isolated so they cannot mate? 3.How are new species created? -Allopatric speciation – -when a geographic barrier isolates a population blocks gene flow -ex. mountain range emerging, new river dividing a field, island -Adaptive radiation -evolution of many diversely adapted species from a common ancestor -Seen on islands – Darwin’s finches -Sympatric speciation -intrinsic factors such as chromosomal changes (plants) or non-random mating alter gene flow -Autopolyploidy -An individual has more than 2 chromosome sets derived from a single species from an error in meiosis -Allopolyploidy -2 different species produce the polyploid hybrid

Figure 24.9 One mechanism for allopolyploid speciation in plants Meiotic error; chromosome number not reduced from 2n to n Unreduced gamete with 4 chromosomes Hybrid with 7 chromosomes Unreduced gamete with 7 chromosomes Viable fertile hybrid (allopolyploid) Normal gamete n = 3 Normal gamete n = 3 Species A 2n = 4 Species B 2n = 6 2n = 10

Chapter 24: The Origin of Species 1.What is a species? 2.What kinds of barriers keep different species isolated so they cannot mate? 3.How are new species created? 4.What is the difference between gradualism & punctuated equlibrium?

Figure Two models for the tempo of speciation Gradualism model. Species descended from a common ancestor gradually diverge more and more in their morphology as they acquire unique adaptations. Time (a) Punctuated equilibrium model. A new species changes most as it buds from a parent species and then changes little for the rest of its existence. (b)

Students -Get handouts -Trouble in Paradise – all terms – underline terms -Evolution FRQs -Turn in lab notebooks – shelf -Galapagos – Thank you! -Phones in bin….muted or off…please & thank you!