L121 Colonization of land: Fungi and Plants slides Notes

Are plants and fungi closely related?

NO! Fungi are more related to animals than to plants

What do plants fall under?

Archaeplastida

What do animals and fungi fall under?

Opishtokont -Unikont

How did fungus and plant play roes in colonizing land on Earth?

They used mutualism to become independent of moist environments and rocks (bacteria were very constrained to rocks)

When was the first fungi found

900mya in aquatic environments

What did plants originate

470 mya in water

When did fungi colonize land

440mya

What nutritional mode are fungi

chemoheterotroph (must be sustained by forming association

ex: lichens are symbiotic with a photosynthetic symbiont

When did plants colonize land

425mya, quickly form mutualism with fungi

Mutualism

Form of ecological interaction where both partners benefit; could be symbiotic or not

ex: fungi extract nutrients from soil/rock and plants provide carbohydrates to the fungi (helped plants colonize)

When did seed plants originate (angiosperm and gymnosperm)

360 mya further expanded what environments a plant could colonize

When did flowering plants originate

140mya, the same time as pollinating insects

What was most likely the common ancestor for opishtokonts

Unicellular, because fungi, choanoflagellates, and nuclei’s can be unicellular

hyphae

thread-like branching tubular filaments that make up the structural body of a fungus

Mycelium

when hyphae come togheter

-extensive mycelial networks maximize surface area over which nutrients can be absorbed

-fungi absorb nutrients from immediate surroundings

How do fungi cell walls help facilitate absorption?

They contain chitin, which allows a cell to expand in response to an influx of H2O

Fruiting body/ reproductive structure

Produces spores for reproduction and dispersal . Contain spore producing structures

mycorrhizae

fungi that forms close associations with plants

Abuscular mycorrhizae

mychorrizal fungi that enters plant cells using hyphae to facilitate exchange of nutrients (form of mutualism)

Ectomycorhizae

mycorrhizal fungi that remain outside cell walls, but weave between plants to facilitate exchange of nutrients in a form of mutualism

Mycorrhizae impact on plants

essential because early plants on land lacked roots and needed nutrients

Describe a fungi life cycle

Fungi have both asexual and sexual reproduction phases in the life cycle, and most of the life cycle is haploid. Both phases produce spores. In the asexual reproduction Spore producing spores produce haploid spores, which then germinate into mycelium, and this cycle repeats. For sexual reproduction, the haploid mycelium of two distinct fungi reach each other, and undergo plasmogamy which is the fusion of the cytoplasm. From there, they enter a heterokaryotic stage which is neither haploid or diploid, and the fungi can exist there for any given amount of time. They then undergo karyogamy which is the fusion of the nuclei, and produce a diploid zygote. The cell undergoes meiosis, which produces haploid spores, which undergo germination, and the cycle could repeat.

fungi sexual reproduction

fusion of the cytoplasm of adjacent mycelia from different individuals

plasmogamy

fusion of the cytoplasm

heterokaryote phase

Shared cytoplasms in the sexual reproduction cycle, neither diploid or haploid, could exist for any period of time

karyogamy

fusion of the nuclei, produce a diploid zygote

What are in archeaplastida

Red Algae, Green Algae ( Chlorophytes, other charophytes, charophyte relative, and plants)

‘true plant’

embryophytes

sporopollenin

a durable polymer that helps charophytes survive in dry conditions

Alternation of Generations

Defining feature of land plants (present in some green algae)

Involves two distinct multicellular phases, one haploid multicellular phase and one diploid multicellular phase

-the life cycle “alternates” between the multicellular phases

-The sporophyte and gametophyte are multicellular and the spores and gametes are unicellular.

Describe the general process of alternation of generations

There is a haploid cycle where unicellular spores replicate through mitosis and create the multicellular haploid gametophyte, which produces a gamete that undergoes fertilization. Once a unicellular diploid zygote is produced its creates the multicellular diploid sporophyte. The cycle continues when the sporophyte produces spores through meiosis.

Sporophyte

A diploid multicellular phase that produces unicellular haploid spores via meiosis

Gametophyte

A haploid multicellular phase that produces unicellular haploid gametes through mitosis

sporangium

part of the sporophyte that directly produces spores; visible in gametophyte dominant organisms

What are the 7 major true plant groups

(3 non vascular) Liverworst, true mosses, Hornworts, lycophytes, monilophytes, gymnosperms, angiosperms ( four vascular, 2 seeded)

What are the two types of vascular tissue

xylem and phloem

Xylem

Transports water/mineral throughout a plant

phloem

organic products like carbohydrates transferred throughout the plant

are lycophytes true mosses?

NO they are taller and have real leaves. Not to be mistaken with the true mosses group

What types of leaves are there in vascular plants

Microphyll and Megaphyll

microphyll leaves

leaves lack branching of vascular tissue, only found among lycophytes

megaphyll leaves

branched vascular tissue; ferns and seed plants

What is the most basal of the 7 true plant groups

Liverworst, followed by true mosses and hornworts

Are non vascular true plants dominant in gametophyte or sporophyte

Non vascular true plants are dominant in gametophyte because the lack the vascular tissue required for transporting nutrients their size is limited. They cannot be dominant in tall states.

Are vascular non seeded true plants dominant in gametophyte or sporophyte

Vascular non seeded true plants are dominant in sporophyte because they have the vascular tissue needed to sustain tall structure.

Role of gametophyte in non seed plants

-gametophyte is independent from the sporophyte, females sustain the embryo

-disperse using spores (rely on flagellated sperm to swim through external water to fertilize the egg) or disperse using spores

How do seed plants disperse

using plan, which are coated in sporopollennin, which helps survive dryness

how are seeded plant eggs fertilized

When the ovule is pollinated, the pollen releases sperm that fertilizes the egg and turn them into seeds, which are durable and can lie dormant for long periods of time

Gymnosperms

coniferous trees and shrubs

-pinecones are ovulate (female, and pollen is male)

monoecious

plants with male and female parts (pinecone trees)

dieicious

plants with a male OR female part

Angiosperm

Flowering seeded plant

what are the male parts of an angiosperm called

the stamen: which consists of the anther and the filament. The anther releases the pollen.

What are the female parts of an angiosperm

The carpel: Which consists of the stigma, the style, and the ovary. The stigma receives the pollen, which receives sperm that travels down the style and into the ovary, where the egg is then fertilized.

How do gymnosperms v. angiosperms deliver pollen

Gymnosperms use water streams or wind, whereas angiosperms use pollinators.