Patterns of Evolution Chapter 17 Section 4

Macroevolution/Microevolution Macroevolution- One genus or family evolves into another….due to large scale changes that take place over long periods of time. Microevolution- Small scale changes within a species to produce new varieties or species in a relatively short amount of time.

Macroevolution/Microevolution Both involve changes in allele frequencies in gene pools The difference is largely one of approach and scale Each offers different insights into the evolution process

Macroevolution/Microevolution 1. Large-scale changes in gene frequencies 2. Occurs over a longer (geological) time period 3. Occurs at or above the level of species in separated gene pools 4. Consists of extended microevolution Microevolution 1. Small-scale changes in gene frequencies 2. Occurs over a few generations 3. Occurs within a species or population in same gene pool 4. Refers to smaller evolutionary changes

Macroevolution/Microevolution 5. Observable 6. Evidence produced by experimentation 7. Example: Bacterial resistance to antibiotics Macroevolution 5. Has not been directly observed 6. Evidence based on remnants of the past 7. Example: Birds from reptiles

Macroevolution/Microevolution

Macroevolution/Microevolution Dog Variability When bred for certain traits, dogs become different and distinctive. This is a common example of microevolution—changes in size, shape, and color—or minor genetic alterations.  It is not macroevolution: an upward, beneficial increase in complexity.  http://www.creationscience.com/onlinebook/webpictures/dogs.jpg

Patterns of Macroevolution These are theories/models of evolution A. Mass Extinctions B. Adaptive Radiation C. Convergent Evolution D. Coevolution E. Gradualism F. Punctuated Equilibrium G. Developmental Genes

Mass Extinctions Many types of living things became extinct at the same time.  Disrupted energy flow caused food webs to collapse Species disappeared. Left habitats/niches open Resulted in burst of evolution of new species in new habitat

Mass Extinctions Possible causes Asteroids hitting earth Volcanic eruptions Continental drift Sea levels changing http://images.google.com/imgres?imgurl=http://www.rosssciencesociety.org.uk/Past%2520Events/Past%2520E3.jpg&imgrefurl=http://www.rosssciencesociety.org.uk/Past%2520Events/Past%2520Events.htm&h=1024&w=1280&sz=91&hl=en&start=8&um=1&tbnid=o1POjijL8bK1pM:&tbnh=120&tbnw=150&prev=/images%3Fq%3Dmass%2Bextinctions%26svnum%3D10%26um%3D1%26hl%3Den%26rls%3DGGLB,GGLB:1969-53,GGLB:en%26sa%3DN

Adaptive Radiation (divergent evolution) The evolution of an ancestral species, into many diverse species, each adapted to a different habitat Many new species diversify from a common ancestor . The new species live in different ways than the original species did.

Adaptive Radiation http://cache.eb.com/eb/image?id=54911&rendTypeId=4

Adaptive Radiation Hawaiian honeycreepers Variation in color and bill shape is related to their habitat and diet http://www.hawaii.edu/environment/ainakumuwai/assets/src_images/honeycreepers.jpg

Convergent Evolution Opposite of divergent evolution (adaptive radiation) Unrelated organisms independently evolve similarities when adapting to similar environments, or ecological niches Analogous structures are a result of this process Example: penguin limb/whale flipper/fish fin The wings of insects, birds, and bats all serve the same function and are similar in structure, but each evolved independently

Convergent Evolution

Convergent Evolution http://www.wasted-disk-space.com/2007/0825/P8257787-2.jpg http://en.wikivisual.com/images/2/24/Oceanic_Whitetip_Shark.png

Convergent Evolution Hummingbird Hawkmoth http://science.kennesaw.edu/~jdirnber/Bio2108/Lecture/LecPhylogeny/25-10-ConvergentEvol-PNL.jpg Hummingbird Hawkmoth

Convergent Evolution Similar body shapes and structures have evolved in the North American cacti...and in the euphorbias in Southern Africa http://images.google.com/imgres?imgurl=http://www.micro.utexas.edu/courses/levin/bio304/evolution/convergent.ex1.gif&imgrefurl=http://www.micro.utexas.edu/courses/levin/bio304/evolution/macroevol.html&h=405&w=350&sz=115&hl=en&start=12&um=1&tbnid=FeV6DLuetThgTM:&tbnh=124&tbnw=107&prev=/images%3Fq%3Dconvergent%2Bevolution%2Bof%2Bcacti%26svnum%3D10%26um%3D1%26hl%3Den%26rls%3DGGLB,GGLB:1969-53,GGLB:en%26sa%3DN

Coevolution The mutual evolutionary influence between two species When two species evolve in response to changes in each other They are closely connected to one another by ecological interactions (have a symbiotic relationship) including: Predator/prey Parasite/host Plant/pollinator Each party exerts selective pressures on the other, thereby affecting each others' evolution

Coevolution http://www.zo.utexas.edu/faculty/sjasper/images/30.18.jpg

Coevolution A fly and an orchid--can influence each other's evolution http://www.zo.utexas.edu/faculty/sjasper/images/30.18.jpg

Coevolution Bumblebees and the flowers the they pollinate have co-evolved so that both have become dependent on each other for survival.

Coevolution Clown Fish and Sea anemone http://www.zo.utexas.edu/faculty/sjasper/images/30.18.jpg

Coevolution Praying Mantis simulates plant to protect itself from predators and eats pests that are attracted to and feed on the plant, so it protects the plant. http://www.zo.utexas.edu/faculty/sjasper/images/30.18.jpg

Gradualism The evolution of new species by gradual accumulation of small genetic changes over long periods of time Emphasizing slow and steady change in an organism Occurs at a slow but constant rate Over a short period of time it is hard to notice

Gradualism http://www.edwardtbabinski.us/whales/whales-graph.jpg

Gradualism http://www.edwardtbabinski.us/whales/whales-graph.jpg

Punctuated Equilibrium Stable periods of no change (genetic equilibrium) interrupted by rapid changes involving many different lines of descent Opposite of gradualism Rapid events of branching speciation

Punctuated Equilibrium

Gradualism or Punctuated Equilibrium

Developmental Genes Development is a progressive process There are a variety of certain developmental genes that regulate the timing of certain events

Lamb born with seven legs Developmental Genes Hox genes – are master control genes Some alter the position of an organ Others alter when things happen http://images.google.com/imgres?imgurl=http://publications.nigms.nih.gov/thenewgenetics/images/ch1_fly2.jpg&imgrefurl=http://publications.nigms.nih.gov/thenewgenetics/chapter1.html&h=197&w=250&sz=47&hl=en&start=10&um=1&tbnid=pVPBIClwjjbCNM:&tbnh=87&tbnw=111&prev=/images%3Fq%3Dlegs%2Bgrowing%2Bout%2Bof%2Bfly%2Bhead%26um%3D1%26hl%3Den%26rls%3DGGLB,GGLB:1969-53,GGLB:en%26sa%3DN Lamb born with seven legs

Hox Genes Determine body plans Function in patterning the body axis Provide the identity of particular body regions http://pharyngula.org/index/weblog/comments/a_brief_overview_of_hox_genes/

Hox Genes Determine where limbs and other body segments will grow in a developing fetus or larva

Hox Genes They are general purpose in the sense that they are similar in many organisms It doesn’t matter if it’s a mouse’s head or a fly’s head that is being built, the same gene directs the process http://evolution.berkeley.edu/evosite/evo101/IIIC6cComplexity2.shtml

(a) normal fruit fly (b) Antennapedia mutation Hox Genes Small changes in such powerful regulatory genes, or changes in genes turned on by them, could represent a major source of evolutionary change http://www.irishscientist.ie/2000/contents.asp?contentxml=156s.xml&contentxsl=insight3.xsl Fruit fly head showing the effects of the Antennapedia gene. This fly has legs where its antennae should be. (a) normal fruit fly (b) Antennapedia mutation

Hox Genes Most insects have two pairs of wings However, flies have one set of flying wings and one set of small balancing wings A single mutation in the gene will result in a fly with two complete sets of flying wings This mutation results in an organ appearing in the wrong place. http://images.google.com/imgres?imgurl=http://courses.bio.psu.edu/fall2005/biol110/tutorials/tutorial13_files/table_25_1b.gif&imgrefurl=http://courses.bio.psu.edu/fall2005/biol110/tutorials/tutorial13.htm&h=315&w=530&sz=28&hl=en&start=15&um=1&tbnid=k48lUfQntwX0_M:&tbnh=78&tbnw=132&prev=/images%3Fq%3DMacroevolution%26svnum%3D10%26um%3D1%26hl%3Den%26rls%3DGGLB,GGLB:1969-53,GGLB:en%26sa%3DN

Hox Genes Hox Genes control development and are common to most organisms. Four groups of similar Hox Genes, shown in color, appear to control related regions of the human body and the fly. Each box represents a single Hox Gene. http://images.google.com/imgres?imgurl=http://www.sfn.org/skins/main/images/brainbriefings/hox_genes_illus.gif&imgrefurl=http://www.sfn.org/index.cfm%3Fpagename%3DbrainBriefings_hoxGenesAndBirthDefects&h=427&w=324&sz=77&hl=en&start=1&um=1&tbnid=4wgj2t05LBkw8M:&tbnh=126&tbnw=96&prev=/images%3Fq%3Dhox%2Bgene%26um%3D1%26hl%3Den%26rls%3DGGLB,GGLB:1969-53,GGLB:en%26sa%3DN Illustration by Lydia Kibiuk, Copyright © 1994 Lydia Kibiuk.

Hox Genes Hox genes determine the form, number, and evolution of repeating parts, such as the number and type of vertebrae in animals with backbones. http://images.google.com/imgres?imgurl=http://www.biology.lsu.edu/heydrjay/1202/Chapter24/Hox%25203.jpg&imgrefurl=http://www.biology.lsu.edu/heydrjay/1202/Chapter24/TheOriginsofForm.html&h=366&w=576&sz=74&hl=en&start=5&um=1&tbnid=If1pVrIIeZaCNM:&tbnh=85&tbnw=134&prev=/images%3Fq%3Dhox%2Bgene%26um%3D1%26hl%3Den%26rls%3DGGLB,GGLB:1969-53,GGLB:en%26sa%3DN In the developing chick (left), the Hoxc-6 gene controls the pattern of the seven thoracic vertebrae (highlighted in purple), all of which develop ribs. In the garter snake (right), the region controlled by the Hoxc-6 gene (purple) is expanded dramatically forward to the head and rearward to the cloaca.

Patterns of Macroevolution Species Flow Chart that are Unrelated Related form in under under in in Intense environmental pressure Inter-relationships Similar environments Small populations Different environments can undergo can undergo can undergo can undergo can undergo Convergent evolution Punctuated equilibrium Adaptive radiation Coevolution Extinction