1.  Genetic Toolkit Video Genetic Toolkit  Read “Animal Body Plans: Homeobox Genes”  What are homeobox genes?  What did Walter Gehring show with his experiment with the eyeless gene?  How do homeobox genes provide evidence that all living things are descended from a common ancestor?  Why are homeotic (aka "homeobox", or Hox) genes considered "master switches?"  How many Hox genes are there in fruit flies, mice and humans? How do scientists know all these carriers of Hox genes arose from a common ancestor?  The fruit fly (Drosophila) and mouse homeobox gene sequences do not look exactly alike. Can you guess why?  Molecular Connections WS- groups of two  All In The Family  Molecular Clocks WS  Common Genetic Code Video Common Genetic Code

3. Natural selection- the main mechanism by which evolution occurs

4. Change over time in the heritable (genetic) traits of a population Process by which modern organisms have descended from ancient organisms

5. What is the difference between a hypothesis and a theory? What do most people think a theory is? What does science say a theory is? What is a law? How does science scaffold the importance of all of these? A theory is a well-supported testable explanation of phenomena observed in the natural world

6.  Born 1809 in England  Studied medicine and theology  Joined HMS Beagle crew in 1831  Ship naturalist  Collected specimens  Made observations  Recorded thoughts Darwin Movie- PBS “Evolution”

8.  Patterns of Diversity  Plants & animals well suited to environments  Similar ecosystems had different animals present  Fossils – preserved remains of ancient organisms  Some resembled living organisms  Some had no living counterpart

9.  Small group of islands west of South America  Observed many different organisms on the islands  Tortoises  Finches  Islands had different climates and different species

10. Darwin observed that the characteristics of many animals and plants varied noticeably among the different islands of the Galapagos What would cause such variation to occur?

11.  Common ideas around his time:  Earth was only a few thousand years old  Neither the planet nor its species had changed  Geological features had been produeced by SUDDEN catastrophic events that humans rarely witnessed

12.  Scientists that helped others recognize that Earth is many millions of years old (Hutton), processes that change Earth in the past are the same processes operating in present (Lyell).  James Hutton- proposed geological forces acted extremely slowly, Earth millions (instead of thosands) of years old  Charles Lyell- processes that shaped Earth a long time ago still continue today, over long periods of time geological changes occur

13.  One of the first scientists to recognize that living things changed over time  Use-Disuse Argument:  Organisms have a tendency toward perfection  Orgas can alter the size/shape of their organs by using bodies in new ways  These new altered characteristics could be inherited

14.  Inheritance of Acquired Traits  Thought acquired traits could be inherited  We now know how traits are inherited (not by behavior but by ________?)

15.  English economist, late 1700s  Noted babies being born faster than people were dying  Human population growing – sooner or later not enough living space and food  War, famine, and disease slowed down growth

16.  If human population continues to grow unchecked, sooner or later there won’t be enough resources (living space, food) for everyone! http://www.fordham.edu/halsall/mod/lect/malthus.gif

17.  Darwin realized the same theory could be applied to plants and animals  Many plants and animals produce lots of offspring and most do not survive or reproduce

18.  1836 – returns from Beagle voyage  1859 – publishes ‘On the Origin of Species’ natural selection  Proposed natural selection is how evolution occurs  Evolution has worked over millions of years and continues today

19.  process of how evolution takes place in nature 1. Struggle for Existence 2. Survival of the Fittest 3. Descent with Modification (variation)

20.  Malthus  High birth rates, shortage of basic needs = competition for resources  Environmental limiting factors (food, living space) prevent all individuals from surviving to reproduce.  Predators that are faster get more food  Prey that are faster or camouflaged avoid being caught

21. A. For all species, if every individual born into a population were to reproduce, the population would grow exponentially Time Population

22. Environmental factors (limiting factors) prevent the majority of individuals from surviving to reproduce- organisms “struggle for existence What are possible limiting factors for a population? Population Time

23.  Fitness = how well suited an organism is to its environment  Ability to survive AND reproduce  Adaptation = inherited characteristic that increases an organisms chance of survival

24.  Orangutan’s long arms  Harmless flies that mimic the sound of an angry bee/wasp  Butterflies of one species that resemble other poisonous butterflies  An insect that looks like a leaf or a stick- camouflage  An opossum playing dead http://animals.nationalgeographic.com/staticfiles/NGS/Shared/St aticFiles/animals/images/800/orangutan-traveling-forest.jpg

25.  For each of the biomes, list ONE adaptation that an organism in that biome has developed to make it “fit” in its environment Tundra Boreal forest Temperate broadleaf forest Temperate grasslands Tropical savannas Deserts

26.  Individuals in the population with more favorable (advantageous) traits survive and reproduce more successfully (high fitness)  Traits not suited to environment die or have few offspring (low fitness) Evolution clipclip

27.  Only certain individuals produce offspring for next generation  Over time, natural selection changes the inherited characteristics of a population

28.  Individuals without advantageous traits die before reproducing.  Individuals with advantageous traits survive to reproduce. These individuals die without reproducing These individuals survive to reproduce Frequency Characteristic

29.  The environment determines what characteristics are “favorable”  Because the environment changes over time, the characteristic that is more favorable for a population changes  Therefore, characteristics of the population change, or evolution occurs

30.  Modeling Camouflage and Natural Selection

31.  Each living species as descended – with changes – from other species over time  All living organisms related to one another  Individuals in a population are not identical to each other. Traits are passed to offspring; traits have a genetic basis:  With different structures  Occupy different habitats

32.  The “average” characteristic or other measure of the population changes over generations Frequency Characteristic average, 1 st gen. These individuals die without reproducing average, 2nd gen. These individuals die without reproducing average, 3rd gen. average, 50 th gen. These individuals survive to reproduce

33.  Members of a population have traits similar to the average trait of the entire population, but they are not identical.  Polygenic trait- controlled by at least 2 genes; can have many possible genotypes and even more phenotypes Frequency Height (cm) Mean (average) height YOUR TURN: Using height as an example, sketch a graph to represent the statement above.

34.  Variation exists in nature (some examples)  Fruit size  Milk production  Speed  Height  Coloration

35.  DNA determines the traits of individuals  Individuals inherit DNA from their parents  This causes the traits of the offspring to resemble the traits of the parents DNAmRNAprotein trait

36. Take out your notes sheet from last class Take out your Peppered Moth Homework On your warm-up paper: 1. What role do you think mutation plays in evolution? 2. Where does mutation fit in with the 4 factors for Natural Selection?

37. http://en.wikipedia.org/wiki/File:Biston.betularia.7200.jpg

38. Before we learn about how mutation influences evolution, let’s discuss the evolution of peppered moths… Dark form Peppered form

39. 1. Describe what trait evolved. 2. Describe how each of the 4 conditions for natural selection exists in the moth example: 1. Variation 2. Inheritance 3. Population limits 4. Selection

40.  The population of peppered moths became darker in color near industrial areas.  Originally, some moths were dark, some moths were peppered (light).  Color is determined by genes inherited from parents.  Not all moths survive to reproduce- some are eaten by birds.  Pollution killed lichen and made the environment darker, so darker moths were better camouflaged and not eaten as much as peppered (light) moths.  This caused the average color of the moth population to become darker

41. Remember that evolution means change in a population’s traits. Scientists agree that evidence shows evolution of the moths has occurred. Natural selection is the mechanism for the change, and recent evidence suggests that camouflage might not be the sole reason for the environmental selection. ?- Sunlight absorption and heat

42. includes Evidence of Evolution Physical remains of organisms Common ancestral species Similar genes which is composed ofwhich indicateswhich implies The fossil record Geographic distribution of living species Homologous body structures Similarities in early development