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Chapter 12Plant and Fungi Diversification

1Plants

Strangler fig treeSeed dropped by birdGrows roots to soilGrows up to sunSpreads around hostHardens to form a treeStrange examples

Ficus4

Plant DiversityPlant groups based on evolutionary changes as plants moved from an aquatic existence to a terrestrial existence.Algae both single celled and multicellular are aquatic. Supported by waterGamete exchange via waterNutrient uptake from water (lack true roots)Lifecycle basis for that of other plants

First terrestrial plants show up around 400-500 mya in fossil record; Alternation of generations recall aphids asex and sex generations alternate. What is advantage?6Adaptations for life on landplantsanimalsRemember animals how does it compare?7Bryophytes non-vascular plantsMost primitive land plantsMosses, hornworts, liverworts

Moss and liverwort8Algae life cycleMoss life cycle

Sperm swims to eggs must be in a moist habitat at least when reproduce9Lower Vascular PlantsFerns, club mosses, horsetails

Horsetail shown; fossil ferns the size of trees10Fern life cycle

Vascular Plants with seeds

2 groups:Gymnosperms AngiospermsSporophyte dominance is completeSperm travels in pollen

No longer needs water or moisture to reproduce. Gametophyte is buried in pollen grain or egg supporting structures; only one species of ginkgo left today12

What key adaptations have contributed to the overwhelming success of seed plants?Pollen transfers sperm to eggs without the need for waterSeeds protect, nourish, and help disperse plant embryosFemale gametophytes of seed plants are protected on the sporophyte plant.All of the aboveOnly a and b are correctAngiosperms Flowering plantsSeed bearing and flower bearingDominant group todayPollen is transported by animals attracted to flowersDouble fertilization

Flower Structure

Angiosperm life cycle

Gametophyte vs sporophyte generations; Note 2 sperm from pollen grain.23Seed Dispersal

The right side of this diagram of a moss life cycle represents:a) the haploid stage.b) the diploid stage.c) the egg.d) meiosis.e) fertilization.

Early seed plants were pollinated by:

a) birds.b) box turtles.c) butterflies.d) bees.e) wind.

The Fungi

Fungi closer to animals than plants

General Characteristics

Note: covered in chapter 17 along with plant diversity31Animal similaritiesHeterotrophic some even parasiticChitin in cell walls (animals dont have cell walls, but exoskeleton of some inverts = chitin; plant cell walls = cellulose)Genetic analysis indicates a shared ancestry about 1 billion years agoEarliest = chytrids have flagellated spores

Mycelium on leaves. Unikonts = animals and fungi3233

Some examples zygote fungus

Sporangium = spore forming body. Meiosis = mixing of genes from 2 mating types.35Example 2 Club fungus

Parasitic forms on plants and animalsErgot replaces plants seeds to disperse. If eaten, causes illness.Smuts and rusts

90% of plants have arbuscules (fungal symbiote in tissues). (Mention glomerulus of kidney.) Ergot LSD, chemicals that help with high blood pressure and stopping bleeding. 39Used in making food such as cheese and breadChemicals used as antibioticsDecompose hard to digest plant tissueLichens = fungus and algal cellsShelf fungus = type of club fungus

What is the heterokaryotic stage of a fungus?The spore forming stage during asexual reproduction.The spore forming stage during sexual reproduction.The stage in which each cell has two different nuclei, one from each parent.The stage in which each cell has two copies of a diploid nucleus that will form spores.Only single celled fungi have this stage and it comes just prior to sexual reproduction.What do you think is the function of the antibiotics that fungi produce in their natural environments?Block the growth of microorganisms, especially prokaryotes that compete with the fungi for nutrients and other resources.This is an example of a symbiotic chemical that helps protect the host of the fungus by killing off its prokaryote pathogens. The chemicals that we use as antibiotics are digestive enzymes that help the fungus breakdown plant tissues for absorption.Fungi are in the chapter on Plant diversity because they are capable of photosynthesis like plants.TrueFalse

Fungi absorb food after digesting it outside their bodies.TrueFalse

Read Chapter 14 Population Ecology