SWBAT explain ways new species are created. Objective: SWBAT explain ways new species are created.

Speciation Notes Chapters 13-15 and 19

Cabbage Lateral buds Terminal bud Flowers and stems Brussels sprouts Figure 13.2 Cabbage Lateral buds Terminal bud Flowers and stems Brussels sprouts Broccoli Figure 13.2 Artificial selection: different vegetables produced as humans have selected for variations in different parts of the wild mustard plant Stem Leaves Kale Kohlrabi Wild mustard 3

Disruptive selection Figure 13.13 Figure 13.13 Three possible effects of natural selection on a phenotypic character (part 3) Disruptive selection 4

A group of organisms that can interbreed and produce viable, fertile offspring. What is a Species?

The process by which one species gives rise to two or more species. It requires some type of separation between the populations. What is Speciation?

Separation that is often caused by habitat location. Different selection pressures from the new environment. Mating is impossible - if meeting again Steps to Speciation

Reproductive Isolation Pre-zygotic – before mating is completed Post-zygotic – after mating is completed Reproductive Isolation

Pre-zygotic Geographic (Location) Temporal (Time) Behavioral (Mating Rituals) Structural (Reproductive Organs) Gametes (Number of Chromosomes) Pre-zygotic

Temporal Isolation Late Winter Late Summer

Structural differences prevent mating Example: Genital openings (arrows) not aligned  No Mating

Hybrid offspring dies Hybrid offspring can’t reproduce Post-zygotic

Sheep x Goat = Offspring will die before birth

Adaptive Radiation An example of adaptive radiation – these species all diverged from a common ancestor (founder species) FOUNDER SPECIES

Other Types of Evolution & Selection Methods Convergent Evolution & Coevolution Sexual Selection

Organisms that are not closely related resemble each other because they have responded to similar environments. Convergent Evolution

Coevolution two (or more) species both adapt to work together

Sexual Selection Females and Males often show different characteristics Some characteristics are selected for within the species Teaching Tips Challenge your students to distinguish between natural selection, sexual selection, and artificial selection. One criterion for comparison is the nature of the selective environment. In natural selection, the interaction is between the organism and its immediate environment. In sexual selection, competition occurs within a species for access to mates. In artificial selection, humans are an important component of the environment, favoring traits of human interest. © 2012 Pearson Education, Inc. 22

Figure 13.14A Figure 13.14A Extreme sexual dimorphism (peacock and peahen) 23

Figure 13.14B Figure 13.14B A contest for access to mates between two male elks 24

Figure 13.14C Figure 13.14C A male gray tree frog calling for mates 25

Biological Evidence for Inheritance

Biological Molecules Biological molecules such as RNA, DNA, and proteins are used by all living organisms, indicating a common evolutionary history.