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Plants - Coggle Diagram

- - - - They have openings which allow CO2 to enter the plant body and allow water and O2 to leave
      - The gametophyte begins its development following spore germination as a branched, filamentous structure called a protonema
      - protonema is unique to mosses
      - some filaments contain photosynthetic, others (called rhizoids) are nonphotosynthetic and anchor protonema to the substrate. After growth, photosynthetic tips divide in 3 dimensions to form buds which develop an apex and produce a leafy moss shoot which produce antheridia or archegonia
      - Gametophytes and sporophytes of many mosses contain a hydroid which dies and leaves a tiny channel through which water travels (the hydroid lacks lignin and cell wall structure)
- - - - Ferns
        
        life cycle
        
        fetilisation forms a zygote
        
        zygote develops into a new sporophyte
        
        the mature sporophyte contains sporangium which disperse spores
        
        spore develops into gametophyte
        
        develops into antheridium which produces sperm or archegonium which produces an egg
        
        the haploid tissue is more insignificant and sporophyte is the main part
        
        They are characterised by large leaves with branching vascular strands
        
        They require liquid water for transfer of male gametes to female gametes so most ferns live in moist areas
        
        The sporangia of ferns typically are borne on a stalk in clusters called sori (which are found on undersurfaces of the leaves)
      - Horsetails
        
        They have reduced tree leaves that form distinct circles around the stem
        
        They have rough silica deposits in their cell walls
        
        They have true roots that branch irregularly and large sporophyte adn small gametophyte
    - - Monilophytes and seed plants form clade called euphyllophytes
      - a synapomorphy of this clade is overtopping (growth pattern in which one branch differentiates from and grows beyond the others
      - the overtopping growth allowed new leaflike structures to evolve like megaphyll which likely arose due to flattening of a portion of a branching stem system that exhibited overtopping growth
      - first megaphylls appeared in Devonian but took 50 million years for large megaphylls to become common (one theory is that high CO2 concentration reduced selection for stomata since less stomata were needed, large leaves with less stomata would absorb heat but could not lose heat fast enough by evaporation so overheating)
  - - - the rhyniophytes did not have roots and were apparently anchored in soil by horizontal portion of stem called rhizomes
      - Rhizomes bore rhizoids, which were water absorbing unicellular filaments, and had aerial branches with sporoangia at the tips (branching was dichotomous)
      - closest relative are rhyniophytes
    - - These are the sister group to vascular plants
      - they have simple leafelike structures called microphylls which are arranged spirally on the stem
      - their growth comes entirely from apical cell division
  - - - It allows the production of many small microspores which are easily transported between plants
      - It results in production of few large megaspores in large megasporangia which provides nutrition and protection for embryo
      - It increases opportunity for long distance cross fertilisation and also increase survival chanve of developing embryo
      - the sperm and egg fertilise into a zygote then embryo then sporophyte
    - - The megaspore develops into a female gametophyte (megagametophyte) that produces only eggs
      - The other type is microspore which is smaller and develops into the male gametophyte (microgametophyte) that produces only sperm
      - The sporophyte produces megaspores in small numbers in megasporangia and micropsores in large numbers in microsporangia
- - - - pollen grain contains sperm and is released from the pollen tube
      - megaspore develops into megagametophyte in the megasporangium
      - it is retained in the megasporangium
      - the ovule develops into the seed after fertilisation, the ovule is made on sporophytic integument and the megasporangium
  - - - microspore- male gametophyte
      - megaspore- female gametophyte
- - - - use colour to direct insect to pollinating area
      - some are specific to certain species but some are random
      - scents attract specific insects
      - Nectar is common incentive
    - - some are self incompatible, with some having alleles that are incompatible and determine whether the seed will germinate
  - - - 2 types of epidermal projections
        
        simple, non-stinging trichomes
        
        structurally complex stinging hairs
      - stinging cell has irritants like formic acid, serotonin, acetylcholine and histamine and easily break off on contact
      - shoots regenerate after which greater stinging hairs
    - - nicotine is an alkaloid and acts as a neurotoxin
    - - waxy secretion
      - has a high levels of flavonoids to deter insects and cause skin irritation
- - - - suggested that it was a modified leaf bearing ovule
      - and the leaf edges curled and fused together
    - - leaflike portion was reduced until only microsporangia remained