Plant and Fungi Diversification Chapter 12

Plants

Strange examples Strangler fig tree Seed dropped by bird Grows roots to soil Grows up to sun Spreads around host Hardens to form a tree Ficus

Plant Diversity Plant 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 water Gamete exchange via water Nutrient 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?

Adaptations for life on land plants animals Remember animals – how does it compare?

Bryophytes – non-vascular plants Most primitive land plants Mosses, hornworts, liverworts Moss and liverwort

Algae life cycle Moss life cycle Sperm swims to eggs – must be in a moist habitat at least when reproduce

Lower Vascular Plants Ferns, club mosses, horsetails Horsetail shown; fossil ferns the size of trees

Fern life cycle

Vascular Plants with seeds 2 groups: Gymnosperms Angiosperms Sporophyte dominance is complete Sperm 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 today

What key adaptations have contributed to the overwhelming success of seed plants? Pollen transfers sperm to eggs without the need for water Seeds protect, nourish, and help disperse plant embryos Female gametophytes of seed plants are protected on the sporophyte plant. All of the above Only a and b are correct

Angiosperms – Flowering plants Seed bearing and flower bearing Dominant group today Pollen is transported by animals attracted to flowers Double fertilization

Flower Structure

Angiosperm life cycle

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

Seed 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 diversity

Animal similarities Heterotrophic – some even parasitic Chitin in cell walls (animals don’t have cell walls, but exoskeleton of some inverts = chitin; plant cell walls = cellulose) Genetic analysis indicates a shared ancestry about 1 billion years ago Earliest = chytrids have flagellated spores Mycelium on leaves. Unikonts = animals and fungi

Some examples – zygote fungus Sporangium = spore forming body. Meiosis = mixing of genes from 2 mating types.

Example 2 – Club fungus

Parasitic forms on plants and animals Ergot – replaces plant’s 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.

Used in making food such as cheese and bread Chemicals used as antibiotics Decompose hard to digest plant tissue Lichens = fungus and algal cells Shelf 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. True False

Fungi absorb food after digesting it outside their bodies. True False

Read Chapter 14 Population Ecology