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Which body system is the most important in maintaining the survival of an entire species?

Which body system is the most important in maintaining the homeostasis (and survival) of an individual organism?. Which body system is the most important in maintaining the survival of an entire species?. Reproduction. Reproduction.

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Which body system is the most important in maintaining the survival of an entire species?

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  1. Which body system is the most important in maintaining the homeostasis (and survival) of an individual organism?

  2. Which body system is the most important in maintaining the survival of an entire species?

  3. Reproduction

  4. Reproduction • The life process by which an organism produces new individuals of the same kind. • This is essential for the survival of the species

  5. Types of Reproduction • Asexual Reproduction • Involves ________ parent and results in one or more offspring that are genetically _________ to that parent. • Cells reproduce byMitosis one identical

  6. Mitosis • A process where a cell divides and creates two daughter cells which are identicalto the parent • Cell Division happens by series of phases • Interphase, prophase, metaphase,anaphase, and telophase(cytokinesis) • I.P.M.A.T.(C).

  7. I.P.M.A.T.C. Overview of mitosis interphase prophase PleaseMake Another Two Cells cytokinesis metaphase anaphase telophase

  8. chromosomes in cell DNA in chromosomes cell 4 single-stranded chromosomes duplicated chromosomes nucleus duplicated chromosomes cell nucleus 4 double-stranded chromosomes DNA must be duplicated…

  9. Mitosis: Dividing DNA & cells • Stage 1: cell copies DNA Copy DNA! DNA cell nucleus INTERPHASE

  10. Mitosis: Dividing DNA & cells • Stage 2: DNA winds into chromosomes • Nuclear membrane disappears • Spindle Fibers/ Centrioles appear duplicated chromosomes Wind up! cell nucleus PROPHASE

  11. double-strandedhuman chromosomes ready for mitosis

  12. Mitosis: Dividing DNA & cells • Stage 3: Chromosomes line up in middle • attached to protein “cables” that will help them move Line up! duplicated chromosomes lined up in middle of cell METAPHASE

  13. Mitosis: Dividing DNA & cells • Stage 4: Chromosomes separate • start moving to opposite ends Separate! chromosomes split & move to opposite ends ANAPHASE

  14. Mitosis: Dividing DNA & cells • Stage 5: Cell starts to divide • Two nuclei • Chromosomes unwind Divide! TELOPHASE

  15. Mitosis: Dividing DNA & cells • Stage 6: DNA unwinds again • cells separate completely (cleavage furrow) • now they can do their every day jobs Bye Bye! cytokinesis

  16. Biology is the only subject in which multiplication is the same thing as division…

  17. Examples of Asexual Reproduction Binary Fission • The cell splits into two identical cells, each containing an exact copy of the original cell's DNA. Nucleus and Cytoplasm divide EQUALLY!

  18. Examples of Asexual Reproduction Budding- where the daughter cell grows out of the parent and gradually increases in size. Yeast cells Hydra Nucleus divides equally Cytoplasm divides unequally

  19. Examples of Asexual Reproduction Spores • Reproductive cell that contains a nucleus and a small amount of cytoplasm • Spores are highly resistant to heat • Spores are capable of growing into a new organism when conditions allow • Produced by bread mold, mushrooms, mosses and ferns

  20. Examples of Asexual Reproduction Regeneration • Development of a new organism from part of a parent • Whole organisms are produced – Starfish! • Replacement of lost body part

  21. Examples of Asexual Reproduction Vegetative Propagation • Part of a plant (root, stem, leaves) grows into a new plant • Seedless fruits & vegetables • Commonly used by farmers = quick, easy & successful!

  22. Sexual Reproduction • Offspring receive half of their genes from one parent and half from the other parent • The genes are carried on chromosomes in sex cells known as gametes • Male gamete is the sperm cell • Female gamete is the ovum (egg)

  23. Sexual Reproduction • Joining of 2 sex cells (egg & sperm) • Do we make egg & sperm by mitosis? No! What if we did, then…. + 46 92 46 egg sperm zygote Doesn’t work!

  24. Sexual Reproduction • Gametes are formed by Meiosis Meiosis (reduction division) • In series of divisions the number of chromosomes is reduced by half

  25. 46 23 46 23 Meiosis makes sperm & eggs • 46 chromosomes to 23 chromosomes • half the number of chromosomes egg meiosis diploid haploid sperm

  26. Sexual Reproduction • Fertilization • Two gametes (Ovum and Sperm) join to create an offspring • Variation • Each offspring gets a unique combination of genes, therefore they are not identical to their parents or siblings.

  27. Sexual Reproduction Meiosis (reduction division) • Spermatogenesis: Creates 4 sperm cells • Oogenesis: Creates 1 ovum and 3 polar bodies

  28. 46 46 46 46 46 46 46 46 46 46 23 23 46 23 23 Putting it all together… meiosis  fertilization  mitosis + development gametes meiosis egg zygote mitosis &development fertilization mitosis sperm

  29. Meiosis & mitosis Meiosis to make gametes • sperm & egg Mitosis to make copies of cells • growth • repair • Development • replacement

  30. Dad Mom The value of meiosis 1 • Consistency over time • meiosis keeps chromosome number same from generation to generation from Mom offspring from Dad

  31. We’re mixing things up here! The value of meiosis 2 • Change over time • meiosis introduces genetic variation • gametes of offspring do not have same genes as gametes from parents • new combinations of traits from Dad variation from Mom offspring new gametes made by offspring

  32. Adding to Variation… prophase 1 Crossing Over– Trading DNA! • During prophase 1, sister chromatids intertwine • homologous pairs swappieces of chromosome • DNA breaks & re-attaches tetrad

  33. JonasBrothers Baldwin brothers Martin & Charlie Sheen, Emilio Estevez Sexual reproduction creates variability Sexual reproduction allows us to maintain both genetic similarity & differences.

  34. CloningA form of asexual reproduction • The nucleus is taken from parent with a complete set of genetic information • Injected into an egg cell which has had its nucleus removed

  35. Cloning cont. • The egg is implanted in a surrogate mother • Result is an organism which is 100% genetically identical to parent

  36. Animals That Have Been Cloned Many more to come… Too many to list…

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