Introduction to Plants

1. Introduction to Plants Biology 11 Mrs. Trevelyan

2. The Kingdom Plantae 1. PRESCRIBED LEARNING OUTCOMES and VOCABULARY 2. VIDEOS: Development of Plants: from Algae to Ferns (20 min) Development of Plants: Seed Plants (20 min) 3. TEXTBOOK PGS • Chapters 21-24 all (pages 556-669)

5. Warmup- Venn Diagram PLANTS ANIMALS

6. Just How Well do You Know Plants? TRUE or FALSE? 1. Apples are more effective at keeping people awake than caffeine? 2. A pineapple is a berry 3. Corn was first grown in central Egypt over 3,000 years ago 4. The asparagus is actually a type of fern with a reduced fern frond 5. If you eat poison ivy, you will be immune to it in the future 6. Pinocchio is made of pine 7. Poinsettia plants are poisonous to humans 8. A notch in a tree will remain the same distance from the ground s the tree grows 9. Peanuts are a vegetable

7. The Origin of Plants • Plants are believed to have evolved from green algae • Both plants and green algae: 1. Use chlorophyll a and chlorophyll b for photosynthesis (green) 2. use starch as primary food storage 3. Have cell walls that contain cellulose 4. Reproduce the same way (alternation of generations)

8. Algae are NOT Plants • Belong to Kingdom Protista (no longer in Kingdom Plantae!) • Eukaryotic • Photosynthetic • Have a mobile stage (swimming sperm/eggs!) • Can’t prevent water loss, so must live in aquatic environments

9. Believe it or Not, it is True.... • French biochemist and Shamengo pioneer Pierre Calleja has invented this impressive streetlight that is powered by algae which absorbs CO2 from the air. We have featured algae-powered lamps before but this one takes out 1 ton (!) of CO2 per year. This is as much CO2 as as a tree absorbs on average during its entire life.

10. The Origin of Plants • The ocean has a stable environment, provides water and support (buoyancy), and sunlight provides energy…so why move to land?  less competition, more sunlight, CO2 and O2 • Land plants evolved around 500 million years ago

11. The Origin of Plants But LAND is difficult to live on… -egg/sperm dispersal? -no support! -temp. fluctuations -dry -herbivores! Adaptations  Specialized Structures

12. The Origin of Plants “Developed” (or “more evolved”) land plants differ from green algae in that they have: 1. A mechanism of REPRODUCTION that protects their reproductive cells and disperses their seeds/sperm 2. “true” ROOTS that anchor the plant and obtain water and nutrients from the soil 3. “true” STEMS that transport water and nutrients up and down the plant via xylem and phloem (=vascular system) 4. STOMATA (holes that open and close) and waxy CUTICLE on leaves to prevent water loss ACTIVITY: Video and worksheet: The Development of Land Plants

13. Kingdom Plantae • Evolutionary tree of plants • From primitive advanced traits that have adapted to land Flowering plants Conifers Ferns Flowers Mosses Seeds  Vascular System Greenalgae ancestor Terrestrial 

14. 1. Reproduction on Land Algae release their eggs and sperm into the ocean during mass spawning... How do Land Plants Reproduce? -primitive plants that live in wet areas release egg/sperm into water (rain) -more advances plants have internalized the egg and sperm in reproductive structures called ovaries and pollen

15. 1. Reproduction on Land • Pollen protects sperm from drying out and travels on wind *yes, if you inhale pollen, you are inhaling plant sperm!!! • Ovaries protects eggs from drying out and provide a landing site for sperm • Embryos protect seeds and also often assist in dissemination of the seed by wind/water/animals

16. 1. Reproduction on Land THE BIG CHANGE: Algae have dominant gametophyte stage (n)  most land plants have a dominant sporophyte stage (2n) • Alternating between these two multicellular stages is called ALTERNTION OF GENERATIONS ACTIVITY: Overview video of Alternation of Generations http://www.youtube.com/watch?v=uJNnZtE00ko (17 min)

17. Some Terms you Should Know… Diploid (2n)- containing two sets of chromosomes Haploid (n)-containing one set of chromosomes Meiosis-when a diploid cell divides to become 4 haploid cells Mitosis- when a diploid cell divides to become two diploid cells Zygote- a fertilized egg (egg and sperm cell combine)

18. A Plant Life Cycle is Different Diploid (2n)multicellularindividual (human) REVIEW OF AN ANIMAL LIFE CYCLE: -one “cycle” with only one multicellular stage -have sperm/egg but NO SPORES -the main adult stage is diploid mitosis meiosis zygote 2n fertilization Haploid (n)unicellular Gametes (sperm or egg)

19. A Plant Life Cycle is Different Diploid (2n)multicellularsporophyte -A PLANT Life Cycle consists of TWO multicellular stages (not just one!). One stage is diploid and one stage is haploid -these stages alternate= ALTERNATION OF GENERATIONS mitosis zygote 2n meiosis fertilization gametes (n) spores (n) mitosis mitosis Haploid (n)multicellular gametophyte

20. Alternation of Generations The same individual switches between two body forms: 1. Sporophyte -Diploid (2n) -Meiosis creates haploid spores (that grow into the gametophyte) 2. Gametophyte -Haploid (1n) -Creates male and female gametes (that can combine to make the sporophyte)

21. In Summary… ACTIVITY: Worksheet- Alternation of Generations

22. 2. A “TRUE” ROOT SYSTEM • Primitive plants have root-like structures called rhizoids (mosses) or rhizomes (ferns) that serve to anchor the plant • More advanced plants have “true” roots. These contain XYLEM and transport water and dissolved minerals that are found in the soil into the plant. PHLOEM transports sugars from the leaves down into the roots for storage/feed root cells. • This is called the VASCULAR SYSTEM and allows plants to be TALL

23. Vascular system in the root

24. How Does Water Move up a Tree? • Water is pulled up by: • evaporation through the leaves • cohesion within the xylem (sticks to self and pulls self up), and • 3. pressure pushing down on the roots • This is called the COHESION-TENSION THEORY

25. 3. A “TRUE” STEM • Primitive plants do not have true stems and as a result they are low-growing. E.g. moss • More evolved plants have “true” stems. These also contain XYLEM and PHLOEM. -XYLEM transports water from the roots to the rest of the plant (generally UPWARDS) -PHLOEM transports sugar from the leaves to the rest of the plant (generally DOWNWARDS)

26. Vascular system in the Stem

27. THE VASCULAR SYSTEM Review QUESTIONS: 1. Where is water absorbed? Lost? 2. Where are minerals absorbed? 3. How is food made? 4. Where is food made? 5. What does xylem do? 6. What does phloem do?

28. 4. STOMATA AND WAXY CUTICLE • Plants have evolved a CUTICLE = a waxy layer on the leaf. This prevents water loss • Plants also have openings on the leaves called STOMATA (singular = stoma). These can open or close to prevent water loss. GAURD CELLS swell/contract to control opening/closing. When open: -CO2 in (for photosynthesis) -O2 out (waste product of photosynthesis) -H2O escapes out

29. What’s the matter with you? • Say it three times fast no seriously, try it... are you saying STOMATA????

30. Other Challenges from moving onto land: GETTING ENOUGH ENERGY • Different strategies for obtaining light: • Growing taller and above other plants – plants began to evolve support cells • Adapt to having less light

31. Other Challenges from moving onto land: DEALING WITH HERBIVORES Thorns, spines, poisons!

33. REVIEW: What adaptations to do these plants have for life on land? ACTIVITY: Worksheet- Section 21.1- Adapting to Life on Land

34. The Members of Kingdom Plantae… Flowering plants Conifers Ferns Flowers Mosses Seeds  Vascular System Greenalgae ancestor Terrestrial 

35. The Members of Kingdom Plantae Bryophytesnon-vascularland plants Pteridophytesseedless vascular plants Gymnospermpollen & “naked” seeds Angiospermflowers & fruit flowering plants conifers flowers mosses ferns pollen & seeds vascular system = water conduction colonization of land Ancestral Protist

36. Bryophytes: Mosses, Liverworts and Hornworts MOSSES LIVERWORTS HORNWORTS

37. Bryophytes How are these plants similar? How are they different from other land plants?

38. Bryophytes 1. General Information: • From the Greek bryo, meaning "moss" and phyt, meaning "plant” • Descendants of the first true land plants • Retain many primitive characters • More than 10,000 species in 700 genera • The three major bryophyte taxa are: • Hepatophyta - The Liverworts • Anthocerophyta - The Hornworts • Bryophyta - The True Mosses

39. Bryophytes 1. General Information: • There are three Classes of mosses now accepted: 1. Sphagnidae - The Peat Mosses (Sphagnum) -most primitive, about 400 species 2. Andreaeidae - The Granite Mosses -Andreaea, about 120 species -Andraeobryum, one species 3. Bryidae- the “True” mosses (about 9500 species)

40. Bryophytes 1. General Information: Are non-vascular land plants • no water transport system (no xylem or phloem) • no true roots (have RHIZOIDS) • No true stems or leaves • Water transported through plant by osmosis Have a very thin waxy cuticle • prevents drying out (although many members can dry out and then rehydrate) • Many are spongy and store water

41. How to Find Water in the Wild Moss holds water like a sponge! ACTIVITY: Video; http://www.youtube.com/watch?v=Dq126DfPu7E

42. Bryophytes 2. STRUCTURE- looking at a moss only: Consists of: a) Gametophyte (green, dominant stage) -has rhizoids, “leaves” b) Sporophyte (beige, grows on gametophyte) -has a CAPSULE with a lid called an OPERCULUM (spores produced here) -Capsule is supported on a stalk called a SETA

43. Bryophytes 3. REPRODUCTION- looking at a moss only • Lifecycle dominated by HAPLOID (n) gametophyte • Has 2 stages: a) The algae-like PROTONEMA is a branching filament of cells b) The plant-like stage which grows from the protonema makes GAMETES (eggs/sperm) • The male gametophyte has ANTHERIDIA that produce sperm. The female gametophyte has ARCHEGONIA that produce eggs.

44. Bryophytes • Flagellated sperm swim in rainwater etc. to reach the egg and form a ZYGOTE • The ZYGOTE develops into the DIPLOID (2n) sporophyte, which is attached to the gametophyte. • The sporophyte has a SPORANGIUM that produces HAPLOID spores, which are dispersed by the wind

45. Moss Reproduction ACTIVITY: Video http://www.youtube.com/watch?v=jcWYAnmm-QE

46. Bryophytes • Mosses can also reproduce by FRAGMENTATION  if a piece breaks off, it can grow into a new individual

47. Bryophytes 4. Importance • PIONEER PLANT- one of the first to move in to new/devestated areas (think rockslide, flood, etc) • Prevents soil erosion along streams • Commercially – peat moss (Sphagnum) is used as a fuel, a soil conditioner, and by florists • Food for mammals and birds

48. BURNS BOG is a Peat Bog 1% of the earth's surface (about half the area of the U.S.) is occupied by peat bogs, making Sphagnum one of the most abundant plants on earth. The peat bogs store 400 billion metric tons of carbon, and so may mitigate the effects of climate change Burns Bog Website: https://www.burnsbog.org/

49. Bryophytes In Summary: Why do mosses need water? Why can’t mosses grow large? Where mustmosses live? ACTIVITY: Moss Life Cycle and Review Questions ACTIVITY: Bryophyta Treasure Hunt Bonus Project

50. Pteridophytes Selaginella Psilotum Horsetails Ferns