Presentation on theme: "Biology Main points/Questions"— Presentation transcript:
1Biology 103 - Main points/Questions Remember how plants and animals reproduce?What else makes plants specialWhat is different about the fungi?Are growth and development the same thing?
2Remember Animal life cycles: Meiosis producesGametes fertilize to make aThis undergoes to produce a .Few animals have asexual reproduction exclusively
3Remember Animal life cycles: Meiosis produces gametes (haploid)Gametes fertilize to make a diploid zygoteZygote undergoes mitosis to produce a multicellular diploid organism.Few animals have asexual reproduction exclusively
5Remember plant life cycles: Meiosis producesHaploid divide (mitosis) to make haploid a(n) _____ plantThis produces – specialized haploid sex cells (like animals)These fuse (called ) to make a (grows into an embryo)
6Remember plant life cycles: Meiosis produces sporesHaploid spores divide (mitosis) to make haploid a “gametophyte” plantGametophytes produce gametes – specialized haploid sex cells (like animals)These gametes fuse (fertilization) to make a zygote (grows into an embryo)
8What is a Plant? Some characteristics: Plants are multicellular eukaryotes.Plants are autotrophicPlants alternate multicellular haploid and multicellular diploid generationsWhat does that mean?
9Plants: Alternate haploid and diploid stages Each is multicellular Different groups have different stages that are most common.
10More Plant characteristics Plants have embryos that are dependent on a mature plant for nutritionPlant cells have cellulose cell walls that provide structural support.
11More Plant characteristics Special adaptations for life on landMost have special transport tissues/structures (roots, vascular tissue…)Can team up with fungi to absorb nutrients (mycorrhizae)Waxy cuticle (slows water loss) & Stomata (allows gas exchange)
13Subcategories of Plants: The plant kingdom has many subdivisions we will talk mostly about four:Mosses – some of the most primitive land plants, lack vascular tissue, dominant gametophyteFerns – seedless vascular plants
14More subcategoriesConifers/gymnosperms – plants with seeds but without flowers and fruitFlowering plants (angiosperms) – plants with flowers and fruit for reproduction
15Last Kingdom to focus on is Fungus Lots of different types we will focus on one – the group that includes the gilled mushrooms you are most familiar withLike other groups most fungi use sexual reproduction at least some of the time.
16What is an Fungus? Four criteria describe the Fungi. Fungal cells have a cell wall of chitin (of course still have membrane!)Fungi are heterotrophic eukaryotesFungi secrete exo-enzymes that digest macromolecules outside their bodies. They then absorb the smaller subunits - causing them to be called absorptive heterotrophs.
17(3) Fungal cells are usually form long thread-like filaments called hyphae The body of a majority of fungi is a complex mat of these hyphae called a mycelliumMushrooms are only a small part of the body of a fungus
18Mass of hyphae – called a mycelium the mycelium is the main “body” of the organismthe mycelium usually contains several meters of hyphaeFigure: 20-1 part aTitle:The filamentous body of a fungus part aCaption:(a) A fungal mycelium spreads over decaying vegetation. The mycelium is composed of (b) a tangle of microscopic hyphae, only one cell thick, portrayed in cross section (c) to show their internal organization. Question Which features of a fungus's body structure are adaptations related to its method of acquiring nutrients?
19Individual hypha each hypha is basically a long string of cells Mitosis generates new cellsFigure: 20-1 part bTitle:The filamentous body of a fungus part bCaption:(a) A fungal mycelium spreads over decaying vegetation. The mycelium is composed of (b) a tangle of microscopic hyphae, only one cell thick, portrayed in cross section (c) to show their internal organization. Question Which features of a fungus's body structure are adaptations related to its method of acquiring nutrients?
20cells communicate through gaps in wall called septa (singular, septum) cytoplasm can flow freely among the cells of the hypha2 haploid nuclei often in a single cell (= dikaryotic)cell wallcytoplasmFigure: 20-1 part cTitle:The filamentous body of a fungus part cCaption:(a) A fungal mycelium spreads over decaying vegetation. The mycelium is composed of (b) a tangle of microscopic hyphae, only one cell thick, portrayed in cross section (c) to show their internal organization. Question Which features of a fungus's body structure are adaptations related to its method of acquiring nutrients?poreseptumtwo haploidnuclei
22(4) Fungal life cycles are dominated by a haploid phase that grows from a haploid spore by mitosis. Most fungi reproduce both sexually and asexuallyFungal life cycles are distinctly different from plants an animals
23Fungal Life Cycle Terminology: Haploid v. DiploidDikaryoticSporeMating type
24Sexual reproduction in Fungi Haploid SporeMitosisMeiosisCells FuseMitosisDikaryotic Cell
25Fungal life cycles main ideas: Meiosis produces sporesHaploid spores divide (mitosis) to make haploid myceliumAny cell can fuse with a cell of another mating type (no specialized gametes!)Cytoplasm joins but not nucleus at first (dikaryotic cell!)
29Fairy Rings A ring of mushrooms may appear overnight. These are the reproductive structures of an underground mycelium (grown from a spore)As the mycelium grows out, it decomposes the organic matter in the soil and mushrooms form just behind this advancing edge.
30Growth vs. DevelopmentThese fairy rings help illustrate the difference between growth and developmentWhat do you think is the difference?The mycellium is growing through the soil but it is only when conditions are right that the fungus triggers the development of mushrooms.
31Growth vs. Development Growth occurs as Cells divideCells increase in sizeDevelopment occurs as cells alter gene expression (cell differentiation)Plants and Animals use different strategies
33Plant Growth & Development In flowering plants we still see haploid (gametophyte) and diploid (sporophyte) stages.Main plant is sporophyteGametophyte is retained by sporophyteLooking at the development of embryoFirst look at flowers
35Stamen is both filament Fig aStamen is bothfilament
36sepal petal stigma anthers style Figure: 25-4 part b Title: A complete flower part b Caption: (b) The amaryllis is a complete monocot flower, with three sepals (virtually identical to the petals), three petals, six stamens, and three carpels (fused into a single structure). The anthers are well below the stigma, making self-pollination difficult.style
37Plant Growth & Development In flowers the sporophyte generation gives rise to the gametophyte in two different placesMale gametophyte produced in AnthersFemale gametophyte is produced in OvuleLets see how…
38Male gametophytes are produced in the anther… Meiosis occurs and produces microsporesThese undergo mitosis to produce pollen (the male gametophyte)
39Female gametophytes are produced in the ovule (inside an ovary)… Meiosis occurs and produces a megaspore
40The megaspore undergoes meiosis to produce an embryo sac (the female gametophyte)
41mature pollen sperm cells (n) tube cell nucleus stigma sperm style Figure: 25-10Title:Pollination and fertilization of a flowerCaption:Question How does double fertilization prevent plants from wasting energy?ovaryintegumentsegg (n)polar nucleiwithin central cell
43What about animal embryos – do we all have shelled eggs?
44Reproduction & Development In most, a small flagellated sperm fertilizes a larger, nonmotile egg to make a zygoteThe zygote undergoes cleavage (mitosis), forming a hollow ball of cells called the blastula.
45Some cells of the blastula then “crawl” inside (gastrulation) This forms a gastrula with 2 tissue layers and an opening (the blastopore!)
46Gastrulation produces three tissue layers Occurs after implantation in humans (and other placental mammals)The placenta provides continuous nutrition during development instead of stored yolk
47Tissues specialize to become... Three tissues are:Ectoderm (outside)Mesoderm (middle)Endoderm (inside)Tissues specialize to become...
48Tissues specialize to become... Three tissues are:Ectoderm (outside)Mesoderm (middle)Endoderm (inside)Tissues specialize to become...
50Protostomes and Deuterostomes there are two major kinds of animals representing two distinct evolutionary linesprotostomesthe mouth develops from or near the blastoporedeuterostomesthe anus forms from or near the blastopore; the mouth forms on another part of the blastula
51Figure 25.34 Embryonic development in protostomes and deuterostomes.
52Protostomes and Deuterostomes deuterostomes also differ from protostomes in three other fundamental waysthe pattern of cleavageprotostomes have spiral cleavage while deuterostomes have radial cleavagefating of cellsit occurs later in deuterostome cleavage than in protostome cleavageorigin of the coelom
53Biology 103 - Main points/Questions Remember how humans reproduce?What makes an organism an animal & how do we subdivide the animal kingdom?What are some other animal reproductive strategies?What is different about the fungi?