1. Biology 103 - Main points/Questions
Remember how plants and animals reproduce?
What else makes plants special
What is different about the fungi?
Are growth and development the same thing?

2. Remember Animal life cycles:
Meiosis produces
Gametes fertilize to make a
This undergoes to produce a .
Few animals have asexual reproduction exclusively

3. Remember Animal life cycles:
Meiosis produces gametes (haploid)
Gametes fertilize to make a diploid zygote
Zygote undergoes mitosis to produce a multicellular diploid organism.
Few animals have asexual reproduction exclusively

4. Fig b

5. Remember plant life cycles:
Meiosis produces
Haploid divide (mitosis) to make haploid a(n) _____ plant
This produces – specialized haploid sex cells (like animals)
These fuse (called ) to make a (grows into an embryo)

6. Remember plant life cycles:
Meiosis produces spores
Haploid spores divide (mitosis) to make haploid a “gametophyte” plant
Gametophytes produce gametes – specialized haploid sex cells (like animals)
These gametes fuse (fertilization) to make a zygote (grows into an embryo)

8. What is a Plant? Some characteristics:
Plants are multicellular eukaryotes.
Plants are autotrophic
Plants alternate multicellular haploid and multicellular diploid generations
What does that mean?

9. Plants: Alternate haploid and diploid stages Each is multicellular
Different groups have different stages that are most common.

10. More Plant characteristics
Plants have embryos that are dependent on a mature plant for nutrition
Plant cells have cellulose cell walls that provide structural support.

11. More Plant characteristics
Special adaptations for life on land
Most 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)

12. More Plant characteristics
Fig b
More Plant characteristics

13. Subcategories 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 gametophyte
Ferns – seedless vascular plants

14. More subcategories
Conifers/gymnosperms – plants with seeds but without flowers and fruit
Flowering plants (angiosperms) – plants with flowers and fruit for reproduction

15. Last 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 with
Like other groups most fungi use sexual reproduction at least some of the time.

16. What is an Fungus? Four criteria describe the Fungi.
Fungal cells have a cell wall of chitin (of course still have membrane!)
Fungi are heterotrophic eukaryotes
Fungi 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 mycellium
Mushrooms are only a small part of the body of a fungus

18. Mass of hyphae – called a mycelium
the mycelium is the main “body” of the organism
the mycelium usually contains several meters of hyphae
Figure: 20-1 part a
Title:
The filamentous body of a fungus part a
Caption:
(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?

19. Individual hypha each hypha is basically a long string of cells
Mitosis generates new cells
Figure: 20-1 part b
Title:
The filamentous body of a fungus part b
Caption:
(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?

20. cells communicate through gaps in wall called septa (singular, septum)
cytoplasm can flow freely among the cells of the hypha
2 haploid nuclei often in a single cell (= dikaryotic)
cell wall
cytoplasm
Figure: 20-1 part c
Title:
The filamentous body of a fungus part c
Caption:
(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?
pore
septum
two haploid
nuclei

21. Septum and pore between cells

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 asexually
Fungal life cycles are distinctly different from plants an animals

23. Fungal Life Cycle Terminology:
Haploid v. Diploid
Dikaryotic
Spore
Mating type

24. Sexual reproduction in Fungi
Haploid Spore
Mitosis
Meiosis
Cells Fuse
Mitosis
Dikaryotic Cell

25. Fungal life cycles main ideas:
Meiosis produces spores
Haploid spores divide (mitosis) to make haploid mycelium
Any cell can fuse with a cell of another mating type (no specialized gametes!)
Cytoplasm joins but not nucleus at first (dikaryotic cell!)

26. Fig a

27. Some fungi have very long-lived dikaryotic mycelia
These are reproductive structures of mycelium that may be huge
Some spread over 3.4 square miles and may be 2500 years old.

28. Fig

29. Fairy 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.

30. Growth vs. Development
These fairy rings help illustrate the difference between growth and development
What 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.

31. Growth vs. Development Growth occurs as
Cells divide
Cells increase in size
Development occurs as cells alter gene expression (cell differentiation)
Plants and Animals use different strategies

32. Plant and Animal development patterns
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

33. Plant Growth & Development
In flowering plants we still see haploid (gametophyte) and diploid (sporophyte) stages.
Main plant is sporophyte
Gametophyte is retained by sporophyte
Looking at the development of embryo
First look at flowers

34. Fig a

35. Stamen is both filament
Fig a
Stamen is both
filament

36. sepal 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

37. Plant Growth & Development
In flowers the sporophyte generation gives rise to the gametophyte in two different places
Male gametophyte produced in Anthers
Female gametophyte is produced in Ovule
Lets see how…

38. Male gametophytes are produced in the anther…
Meiosis occurs and produces microspores
These undergo mitosis to produce pollen (the male gametophyte)

39. Female gametophytes are produced in the ovule (inside an ovary)…
Meiosis occurs and produces a megaspore

40. The megaspore undergoes meiosis to produce an embryo sac (the female gametophyte)

41. mature pollen sperm cells (n) tube cell nucleus stigma sperm style
Figure: 25-10
Title:
Pollination and fertilization of a flower
Caption:
Question How does double fertilization prevent plants from wasting energy?
ovary
integuments
egg (n)
polar nuclei
within central cell

42. Development into an embryo

43. What about animal embryos – do we all have shelled eggs?

44. Reproduction & Development
In most, a small flagellated sperm fertilizes a larger, nonmotile egg to make a zygote
The zygote undergoes cleavage (mitosis), forming a hollow ball of cells called the blastula.

45. Some cells of the blastula then “crawl” inside (gastrulation)
This forms a gastrula with 2 tissue layers and an opening (the blastopore!)

46. Gastrulation produces three tissue layers
Occurs after implantation in humans (and other placental mammals)
The placenta provides continuous nutrition during development instead of stored yolk

47. Tissues specialize to become...
Three tissues are:
Ectoderm (outside)
Mesoderm (middle)
Endoderm (inside)
Tissues specialize to become...

48. Tissues specialize to become...
Three tissues are:
Ectoderm (outside)
Mesoderm (middle)
Endoderm (inside)
Tissues specialize to become...

50. Protostomes and Deuterostomes
there are two major kinds of animals representing two distinct evolutionary lines
protostomes
the mouth develops from or near the blastopore
deuterostomes
the anus forms from or near the blastopore; the mouth forms on another part of the blastula

51. Figure 25.34 Embryonic development in protostomes and deuterostomes.

52. Protostomes and Deuterostomes
deuterostomes also differ from protostomes in three other fundamental ways
the pattern of cleavage
protostomes have spiral cleavage while deuterostomes have radial cleavage
fating of cells
it occurs later in deuterostome cleavage than in protostome cleavage
origin of the coelom

53. Biology 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?