How are genes passed down?

1. How are genes passed down? Gen. Biology

2. Body Cells • One cell’s DNA passed to the next cell? • Mitosis • DNA in cell is copied and cell splits giving a copy of the DNA to the new daughter cell.

3. Phases of Mitosis • Prophase • Metaphase • Anaphase • Telophase

4. Prophase • DNA condense. • Nuclear membrane starts to break down. • Spindle fibers start to form.

5. Metaphase • Chromosomes line up in middle of the cell. • Spindle fibers attach to the chromosome center --- called the centromere.

6. Anaphase • Spindle fibers pull chromosomes apart. • Move to opposite ends of the cell.

7. Telophase • Nuclear membranes reappear. • Cell pinches down the middle. • In plant cells, no pinching, a cell plate forms.

8. Cytokinesis • Cell splits into two new cells.

9. Interphase • Time in between mitosis. • Cell grows.

11. Sex cell division • Meiosis

12. Phases of Meiosis • Prophase I • Metaphase I • Anaphase I • Telophase I • Prophase II • Metaphase II • Anaphase II • Telophase II

13. Meiosis I • Cell divides the same as in Mitosis. • Before Meiosis II, the second division, the chromosomes do not replicate.

14. Meiosis II • The two daughter cells split. • Ending with four cells with half the set of chromosomes since DNA replication didn’t occur before the division.

15. Why do we want half the set of chromosomes in sex cells? • When fertilization occurs the zygote has half of mother’s DNA and half of father’s DNA. • If they received all of their father’s and mother’s DNA they would have too much DNA.

16. Variation • Variation of humans, animals, and plants is due to mutations. • Mutations are changes in the DNA sequence.

17. Mutations • Mutations can be beneficial or harmful.

18. Beneficial • Help the organism better survive. • Ex. Industrial Revolution and the Peppered moths. A mutation that makes the moth black is usually harmful because predators can spot them easily on white birch trees. Industrial revolution covered soot over trees. Now the black moths blend in better. White moths now are spotted easier and eaten. This mutation was passed on through generations because these moths survived and reproduced.

19. Harmful • Hemophilia • Colorblindness

20. Humans’ mutations • Some of our DNA does not code for anything, its called junk DNA. • This junk DNA is different in all people. • This junk DNA is used to trace back our ancestral migrations. • Also used for DNA fingerprinting. • Mutations that occur in the junk DNA show the different migratory patterns.

21. Survival of the Fittest • Organisms with beneficial traits can better survive and pass on their traits to the next generation. • The environment that the organism is in and the organism’s traits determine if they will survive better.

22. Charles Darwin • Sailed on the Voyage of the Beagle • Went around the world. • Did a lot of research in the Galapagos Islands. • Studied finches’ beaks. • On the different islands the beaks were different. • The were different because of the different foods available.

23. Ecosystems • The earth has a biosphere. • The only planet in the solar system with this. • Biosphere – a layer of soil, water, and air that sustains life. • Bio = life

24. Does the Biosphere differ from place to place? • Yes, even if you travel to different areas of the United States there are different biospheres. • The plants and animals in the marshes at the edge of eastern Pennsylvania’s Delaware River look nothing like the plants and animals of western Pennsylvania’s Allegheny National Forest.

25. Ecosystem • A group of living organisms that interact with one another and the nonliving physical environment as one unit. • Terrestrial – land • Terrestrial ecosystem – is on land. • Forest • Desert • Grassland BrainPop - Ecosystems

26. What organisms are found in an ecosystem? • The plants and animals found in an ecosystem depend primarily on the local climate and soils in an area. • Climate vs. Weather? • Climate – the temperature and precipitation of an area for a long period of time. • Weather – the temperature and precipitation of an area each day.

27. What ecosystems are found in PA? • Forest ecosystems • Covers more than half of the state. • Oak-hickory – most common type of forest ecosystem, 47% of the forested area, central and southern parts of the state. • Second most common is the northern hardwood forest, covers 38 percent. • Birch, sugar maple, beech, and black cherry trees.

28. Aquatic Ecosystems • Water ecosystems • Freshwater ecosystems include: • Ponds • Lakes • Rivers • Streams • Wetlands

29. Marine or Saltwater Ecosystems • Salt water ecosystems include: • Estuaries • Coastal marshes • Coral reefs • Open ocean

30. Hierarchy of Living Things • Organism – any form of life. • Ex. Bacterium to a bear. Species – group of organisms that are alike in several ways, including appearance and genetic makeup, and that can breed with one another to produce healthy offspring.

31. Population • Group of individuals of the same species found in a given area or located in the same area at a given time. • Ex. Group of white-tailed deer in an oak-hickory forest.

32. Community • Populations of living organisms that interact with one another in an ecosystem. • Vary in size • Many different organisms interacting. • Populations within the community can change overtime.

33. Habitat • Place where a particular species lives and from which it obtains what it needs for survival. • Ex. Atlantic ocean, lake Erie, a rotting log

34. Biotic Factors in an Ecosystem • Ecosystems have both living and nonliving things. • Biotic factors – living parts of an ecosystem that interact with each other. • Ex. Plants, animals, fungi, and microorganisms

35. Abiotic Factors • The biotic factors also interact with and affect abiotic factors. • Abiotic – nonliving factors. • Ex. Physical and chemical parts: • Surface water, soil nutrients • Groundwater, temperature, • Air, precipitation • Wind , energy from the sun. • They influence and support the biotic parts of the ecosystems.

36. In Aquatic Ecosystems • Abiotic Factors include: • Currents • Salinity • Temperature • Penetration of sunlight in water • Concentration of nutrients in the water

37. Why are Abiotic factors important? • For example trees could not live and produce food without water, solar energy, and nutrients from the soil. • Each species survives best within a certain range of environmental conditions – a specific range of temperature, soil, water pH, latitude, and amount of precipitation. • ToleranceLimits – conditions that define the physical limits within which an organism can survive.

38. Six Kingdoms • BrainPop – Six Kingdoms • Bacteria • Protists • Animals • Plants • Fungi • Archae