Eukaryotes and Their Classification

These flashcards cover key terms and concepts related to eukaryotes, fungi, protists, and plant evolution, as indicated in the lecture notes.

Eukaryotes evolution timeline

Eukaryotes evolved approximately 1.5 billion years ago.

Five supergroups of Domain Eukarya

Excavata, SAR, Archaeplastida, Amoebozoa, Opisthokonta.

Fungi supergroup

Fungi belong to the Opisthokonta supergroup.

Traditional classification method for fungi

Morphology, which is based on physical traits.

Modern methods for classifying fungi

Molecular data and phylogenetic analysis.

Importance of molecular techniques

Molecular techniques show true evolutionary relationships.

Genetic relationship of fungi

Fungi are closer to animals than to plants.

Monophyletic phyla of fungi

Fungi are made up of 6 monophyletic phyla.

Validity of Zygomycota

Zygomycota is invalid because it is not monophyletic.

Characterization of fungi

Fungi are heterotrophs that absorb nutrients, have a cell wall made of chitin, store glucose as glycogen, and function as decomposers.

Unicellular fungi

Unicellular fungi are called yeasts.

Hyphae

Hyphae are filamentous structures of fungi.

Mycelium

Mycelium is the mass of hyphae that forms the body of fungi.

Septate vs Coenocytic

Septate hyphae have divisions, while coenocytic hyphae do not.

Fungal fruiting body

The fruiting body is a structure that produces spores.

High surface area benefit

High surface area increases nutrient absorption.

Definitions of monokaryotic, dikaryotic, heterokaryotic, homokaryotic

Monokaryotic = 1 nucleus, dikaryotic = 2 nuclei, heterokaryotic = different nuclei, homokaryotic = same nuclei.

Unusual division in fungi

In some fungi, the nucleus divides but the cell does not.

Asexual vs sexual reproduction in fungi

Both produce spores; sexual reproduction results in more variation.

What happens when two hyphae fuse?

Their fusion results in plasmogamy and the dikaryotic stage.

Four types of fungal spore structures

Zoospores, zygosporangia, basidia, asci.

Symbiosis

Symbiosis is close interaction between species, which can be mutualism, parasitism, or commensalism.

Lichens

Lichens are symbiotic associations of fungus and algae.

Mycorrhizae

Mycorrhizae are symbiotic relationships between fungi and plant roots.

Three forms of lichens

Crustose, foliose, and fruticose.

Importance of lichens for land colonization

Lichens help plants absorb nutrients.

Fungal networks' benefit to plants

Fungal networks share nutrients and signals between plants.

Basidiomycota

Basidiomycota, also known as club fungi, produce basidium and include mushrooms.

Basidiomycota life cycle

The life cycle involves plasmogamy, dikaryotic phase, karyogamy, meiosis, and spore formation.

Definitions of plasmogamy, karyogamy, meiosis, germination

Plasmogamy = cytoplasm fusion, karyogamy = nuclei fusion, meiosis = chromosome reduction, germination = spore growth.

Ascomycota

Ascomycota, or sac fungi, produce spores in asci and include yeasts.

Asexual vs sexual reproduction in Ascomycota

Asexual reproduction produces conidia, while sexual reproduction produces asci spores.

Yeast reproduction method

Yeasts reproduce by budding.

Process of fermentation

Fermentation involves converting glucose into ethanol and CO₂ and is used in bread, beer, and wine production.

Glomeromycotina importance

Glomeromycotina form mycorrhizae and helped plants evolve.

Zygomycetes

Zygomycetes are commonly known as bread molds.

Zygomycete reproduction methods

Asexual reproduction involves sporangia; sexual reproduction involves zygosporangium and zygospores.

Key differences between fungal groups

Zygomycetes form zygosporangium; Ascomycota form asci; Basidiomycota form basidia.

Importance of protists

Protists are important as the first eukaryotes.

Unicellular or multicellular first eukaryotes

The first eukaryotes were unicellular.

Evolutionary descendants of early eukaryotes

Plants, animals, and fungi evolved from early eukaryotes.

Definition of protists

Protists are defined as organisms that are not plants, animals, or fungi.

Levels of organization in protists

Protists can be unicellular, colonial, or multicellular.

Nutritional strategies of protists

Protists can be autotrophs, heterotrophs, or mixotrophs.

Movement structures in protists

Protists may use cilia, flagella, or pseudopodia for movement.

Number of supergroups containing protists

Protists are found in all five supergroups.

Excavata similarities

Excavata share a cytoskeleton structure and a groove.

Euglenozoan movement

Euglenozoans can change shape for movement.

Euglenids' mixotrophic nature

Euglenids are considered not true plants or animals due to their mixotrophic abilities.

Euglenid structures and functions

Contractile vacuole for water regulation, flagella for movement, stigma for light detection, and chloroplasts for photosynthesis.

Stramenopile features and examples

Stramenopiles are characterized by hairy flagella and include brown algae, diatoms, and oomycetes.

Characteristics of brown algae

Brown algae are marine, large, and exhibit alternation of generations.

Functions of stipe, blade, and air bladder in brown algae

Stipe provides support, blade is for photosynthesis, and air bladder aids buoyancy.

Diatoms characteristics

Diatoms have silica shells and exhibit radial or bilateral symmetry.

Diatoms' ecological importance

Diatoms form the base of aquatic food webs.

Diatomaceous earth

Diatomaceous earth is made up of fossilized diatoms.

Oomycetes characteristics

Oomycetes are either parasites or decomposers.

Physical differences between brown algae and diatoms

Brown algae are large, while diatoms have glass-like shells.

Archaeplastida groups

The Archaeplastida groups include red algae, green algae, charophytes, and plants.

Traits of red algae

Red algae are marine and contain red pigments.

Growth depth of red algae

Red algae grow deep to absorb blue light.

Traits of green algae

Green algae contain chlorophyll a & b.

Closest relatives of land plants

Charophytes are the closest relatives of land plants.

Lineages of green algae

The two lineages of green algae are Chlorophyta and Charophytes.

Chlamydomonas, Volvox, Ulva differences

Chlamydomonas are unicellular, Volvox are colonial, and Ulva are multicellular.

Cell types in Volvox

Volvox consists of reproductive and vegetative cells.

Colonial vs multicellular organisms

Colonial organisms are independent, while multicellular organisms have specialized cells.

Closest charophytes

Charales and Coleochaetales are the closest charophytes.

Land plant challenges

Challenges include drying, UV radiation, and reproduction.

Relationship of bryophytes to green algae

Bryophytes evolved from green algae.

Key evolutionary steps in bryophytes

Key steps include the development of a cuticle, stomata, and embryo protection.

Roles of fungi in bryophytes

Fungi assist in nutrient uptake for bryophytes.

Land challenges faced by bryophytes

Bryophytes face water loss, UV radiation, and reproduction challenges.

Cuticle vs stomata functions

Cuticle prevents water loss, stomata facilitate gas exchange.

Importance of absence of vascular tissue

No vascular tissue limits plant size.

UV influence on plant dominance

UVA radiation leads to diploid dominance.

Traits of land plants

Land plants exhibit alternation of generations.

Basic life cycle of bryophytes

Their life cycle progresses from sporophyte to spores to gametophyte to gametes.

Importance of embryo protection

Embryo protection is important for preventing drying.

Generational trends in bryophytes

Bryophytes are gametophyte dominant.

Characteristics of bryophytes

Bryophytes are small, lack vascular tissue, and require water.

Moist environments for bryophytes

Mosses need moist environments as sperm require water to reach eggs.

Moss life cycle characteristic

The moss life cycle is gametophyte dominant.

Comparison of bryophyte groups

Groups include liverworts, mosses, and hornworts.

Rhizoids vs roots

Rhizoids help anchor plants, but do not absorb nutrients like true roots.

Structure differences in bryophytes

Bryophytes lack true organs.

Environmental origin of gymnosperms

Gymnosperms evolved from spore plants.

Importance of seeds in gymnosperms

Seeds protect and nourish the embryo.

Homo vs heterosporous distinctions

Gymnosperms are heterosporous, producing different types of spores.

Male gametophyte in gymnosperms

The male gametophyte is pollen.

Dispersal mechanisms in seedless plants

Wind is the primary dispersal method for gymnosperms, while water is used in seedless plants.

Female gametophyte location in gymnosperms

The female gametophyte is located within the ovule.

Reduced gametophyte significance

The reduction provides protection.

Traits of gymnosperms

Gymnosperms are characterized by naked seeds.

Conifer traits

Conifers have needle-like leaves and are cold-resistant.

Survival traits in gymnosperms

Gymnosperms have features like thick cuticles and resin.

Life cycle type of gymnosperms

Gymnosperms have a heterosporous life cycle.

Male vs female cones in gymnosperms

Male cones produce pollen, while female cones produce ovules.

Fertilization in pine trees

There is no double fertilization in pine trees.

Water necessity in gymnosperm fertilization

Pollen tubes eliminate the need for water in fertilization.