1. Reproduction 1. Hand in your Allele Frequency Activity to the inbox. 2. Study your notes from yesterday in preparation for a short quiz… 1. Hand in your Allele Frequency Activity to the inbox. 2. Study your notes from yesterday in preparation for a short quiz…

2. Homework  Paper due 4/2

3. Recall Quiz  Answer these questions on a piece of paper.  1. Complete this sentence from yesterday’s objective: “Individuals and ______ vary.”  2. Define “allele frequency.”  3. Complete this sentence: “Phenotypic variations come from _______ variations.”  4. Name the two big sources of new phenotypes.  5. True or false, variations can be inherited.  Answer these questions on a piece of paper.  1. Complete this sentence from yesterday’s objective: “Individuals and ______ vary.”  2. Define “allele frequency.”  3. Complete this sentence: “Phenotypic variations come from _______ variations.”  4. Name the two big sources of new phenotypes.  5. True or false, variations can be inherited.

4. Recall Quiz  1. Complete this sentence from yesterday’s objective: “Individuals and groups vary.”  2. Allele frequency is how often an allele occurs in a gene pool. (Acceptable alternatives are okay, check them with me)  3. Complete this sentence: “Phenotypic variations come from genotypic variations.”  4. Name the two big sources of new phenotypes: Crossing-over and mutation.  5. True or false, variations can be inherited.  1. Complete this sentence from yesterday’s objective: “Individuals and groups vary.”  2. Allele frequency is how often an allele occurs in a gene pool. (Acceptable alternatives are okay, check them with me)  3. Complete this sentence: “Phenotypic variations come from genotypic variations.”  4. Name the two big sources of new phenotypes: Crossing-over and mutation.  5. True or false, variations can be inherited.

5. Conclusions from Yesterday  Individuals and groups vary.  Genetic variation can be expressed as “allele frequency” = how often an allele occurs in a gene pool.  Phenotypic variations come from genotypic variations.  So, these variations are inherited.  New phenotypes can arise from rare, random, regular events:  Crossing-over gives you new combinations of alleles. Mutation gives you brand new alleles.  Individuals and groups vary.  Genetic variation can be expressed as “allele frequency” = how often an allele occurs in a gene pool.  Phenotypic variations come from genotypic variations.  So, these variations are inherited.  New phenotypes can arise from rare, random, regular events:  Crossing-over gives you new combinations of alleles. Mutation gives you brand new alleles.

6. Objectives Today  Be able to explain:  How much reproduction occurs  What the result of that is  Reproduction rates. When I was growing up, there were these barn swallows under the eve of our house, and their babies built nests of their own when they grew up…  Be able to explain:  How much reproduction occurs  What the result of that is  Reproduction rates. When I was growing up, there were these barn swallows under the eve of our house, and their babies built nests of their own when they grew up…

7. Reproduction Rates  Barn swallows lay two clutches each year, an average of 5 nestlings in each clutch. Nestlings take only one year to grow up, so they start laying their own nests the very next year.  The barn swallows first arrived at my house in the summer of 1983. I want us to graph their reproduction up through 2005, when I last saw them.  Make a table with two columns, year and # of barn swallows.  And I’d like a volunteer up front, please.  Barn swallows lay two clutches each year, an average of 5 nestlings in each clutch. Nestlings take only one year to grow up, so they start laying their own nests the very next year.  The barn swallows first arrived at my house in the summer of 1983. I want us to graph their reproduction up through 2005, when I last saw them.  Make a table with two columns, year and # of barn swallows.  And I’d like a volunteer up front, please.

8. Year# of Barn Swallows 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993…

9. Reproduction Rates  Why wasn’t I buried in barn swallows? All those corn kernels came from just one pair of them! And in 1983, there were millions of them in the U.S.! Why aren’t we all swimming in barn swallows?  And it’s not just barn swallows.  With your partner, make tables like we just did to solve these problems on a fresh sheet of paper (this is for a grade):  P.S. You will need to recall scientific notation for these.  Why wasn’t I buried in barn swallows? All those corn kernels came from just one pair of them! And in 1983, there were millions of them in the U.S.! Why aren’t we all swimming in barn swallows?  And it’s not just barn swallows.  With your partner, make tables like we just did to solve these problems on a fresh sheet of paper (this is for a grade):  P.S. You will need to recall scientific notation for these.

10.  1. The bacteria Escherichia coli or E. coli live on your skin. They split in half, called binary fission, to reproduce asexually. They do this every 15 minutes. An E. coli individual finds a patch of your skin that’s miraculously unoccupied so far, and there’s enough space for a whopping 100,000 E. coli! How long will it be before the E. coli’s descendents have out- reproduced the space available?  2. A pair of 1-year-old striped bass are dumped into a fishless bay. These fish have a lifespan of 40 years, and produce an average of 250,000 eggs a year. Five years later, if nothing has happened to stop them, how many striped bass would be in this bay? (Remember, every two bass will make 250,000 eggs, so it’s simpler to calculate it as 125,000 eggs per one bass.)  1. The bacteria Escherichia coli or E. coli live on your skin. They split in half, called binary fission, to reproduce asexually. They do this every 15 minutes. An E. coli individual finds a patch of your skin that’s miraculously unoccupied so far, and there’s enough space for a whopping 100,000 E. coli! How long will it be before the E. coli’s descendents have out- reproduced the space available?  2. A pair of 1-year-old striped bass are dumped into a fishless bay. These fish have a lifespan of 40 years, and produce an average of 250,000 eggs a year. Five years later, if nothing has happened to stop them, how many striped bass would be in this bay? (Remember, every two bass will make 250,000 eggs, so it’s simpler to calculate it as 125,000 eggs per one bass.)

11. Answers  1. E. coli question. Answer = 4 hours.  (At 3:45, they had 65,536 bacteria. At 4:00, they have 131,072 bacteria.)  2. Striped bass question. Answer = 6.104 x 10 25, or 6,104,000,000,000,000,000,000,000 bass in 5 years.  Starting with a population of two. For year one, 2 + (2 x 125000) = 250002. Year two, 250002 + (250002 x 125000) = 31250500002. Year three, 31250500002 + (31250500002 x 125000) = 3.906 x 10 15. Year four, 3.906 x 10 15 + (3.906 x 10 15 x 125000) = 4.883 x 10 20. Year five, 4.883 x 10 20 + (4.883 x 10 20 ) = 6.104 x 10 25.  1. E. coli question. Answer = 4 hours.  (At 3:45, they had 65,536 bacteria. At 4:00, they have 131,072 bacteria.)  2. Striped bass question. Answer = 6.104 x 10 25, or 6,104,000,000,000,000,000,000,000 bass in 5 years.  Starting with a population of two. For year one, 2 + (2 x 125000) = 250002. Year two, 250002 + (250002 x 125000) = 31250500002. Year three, 31250500002 + (31250500002 x 125000) = 3.906 x 10 15. Year four, 3.906 x 10 15 + (3.906 x 10 15 x 125000) = 4.883 x 10 20. Year five, 4.883 x 10 20 + (4.883 x 10 20 ) = 6.104 x 10 25.

12. Reproduction Rates  The actual barn swallow population at the house? The same two parents kept coming back to their nest, and between 1983 and 2005, only two of their babies made nests of their own. So… four.  All organisms make more offspring than can possibly survive. The things that keep all those offspring from surviving are called “limiting factors,” and there are a lot of them.  Brainstorm, what are some specific things that would prevent all of an organism’s offspring from surviving?  The actual barn swallow population at the house? The same two parents kept coming back to their nest, and between 1983 and 2005, only two of their babies made nests of their own. So… four.  All organisms make more offspring than can possibly survive. The things that keep all those offspring from surviving are called “limiting factors,” and there are a lot of them.  Brainstorm, what are some specific things that would prevent all of an organism’s offspring from surviving?

13. Reproduction Rates  Limiting factors like…  Not enough vitamins and minerals to go around  Not enough oxygen, nitrogen, or other elements to go around  Not enough water to go around  Not enough food to go around  Disease  Parasites  Predators  Weather and the elements  Fires and disasters  Pollution and radiation  Not enough physical space to go around  Limiting factors like…  Not enough vitamins and minerals to go around  Not enough oxygen, nitrogen, or other elements to go around  Not enough water to go around  Not enough food to go around  Disease  Parasites  Predators  Weather and the elements  Fires and disasters  Pollution and radiation  Not enough physical space to go around

14. Reproduction Rates  If you have a limited amount of a resource, and a thousand times more individuals who need it than can have it, what happens?

15. Reproduction Rates  If you have a limited amount of a resource, and a thousand times more individuals who need it than can have it, what happens?  Competition is the inevitable result for all living things. (Very fierce competition, at that…)  Let me know if it doesn’t make sense why competition happens because there are too many babies, I’d be happy to clarify this important point!  If you have a limited amount of a resource, and a thousand times more individuals who need it than can have it, what happens?  Competition is the inevitable result for all living things. (Very fierce competition, at that…)  Let me know if it doesn’t make sense why competition happens because there are too many babies, I’d be happy to clarify this important point!

16. Flowchart  Organisms produce many offspring.

17. Flowchart  Resources to support offspring are limited.

18. Flowchart  There is competition for survival and reproduction.

19. Conclusion  Organisms reproduce more than can possibly survive.  Competition is the inevitable result.  If any of the conclusions from yesterday or today do not make complete sense, please ask me to be clearer!  Not understanding today and yesterday and then going forward will be like trying to go master Punnett Squares if you don’t know what a gene or a trait are. It won’t work.  Organisms reproduce more than can possibly survive.  Competition is the inevitable result.  If any of the conclusions from yesterday or today do not make complete sense, please ask me to be clearer!  Not understanding today and yesterday and then going forward will be like trying to go master Punnett Squares if you don’t know what a gene or a trait are. It won’t work.

20. All Conclusions So Far Variation  Individuals and groups vary.  Genetic variation can be expressed as “allele frequency” = how often an allele occurs in a gene pool.  New phenotypes can arise from rare, random, regular events:  Crossing-over gives you new combinations of alleles. Mutation gives you brand new alleles. Inheritance  Phenotypic variations come from genotypic variations.  So, these variations are inherited. Struggle For Life  Organisms reproduce more than can possibly survive.  Competition is the inevitable result. Variation  Individuals and groups vary.  Genetic variation can be expressed as “allele frequency” = how often an allele occurs in a gene pool.  New phenotypes can arise from rare, random, regular events:  Crossing-over gives you new combinations of alleles. Mutation gives you brand new alleles. Inheritance  Phenotypic variations come from genotypic variations.  So, these variations are inherited. Struggle For Life  Organisms reproduce more than can possibly survive.  Competition is the inevitable result.

21. Remainder  There will be another short quiz tomorrow, be prepared.  For the remainder of the period, congratulations on getting through the full lesson! You have the rest of the hour as a study hall.  You may either work on homework for another class, or read from my “science library.”  Study hall, not social hour. If you’re chatting, you must also be working diligently.  There will be another short quiz tomorrow, be prepared.  For the remainder of the period, congratulations on getting through the full lesson! You have the rest of the hour as a study hall.  You may either work on homework for another class, or read from my “science library.”  Study hall, not social hour. If you’re chatting, you must also be working diligently.