Biol 1202 | Exam 3

Chapters 28-33, including as many images as possible on terms

Protists

Most structural and Functionally diverse group of eukaryotes. Unicellular and Multicellular. Photoautotrophs, Heterotrophs, Mixotrophs. Asexual and Sexual Reproduction

Photoautotroph

Contains chloroplasts and does photosynthesis

Heterotroph

Absorb organic molecules or ingest food from an outside source

Mixotroph

CAn do photosynthesis but also has heterotrophism

Four Supergroups of Eukaryotes

Excavata, SAR (Stramenophiles, Alveolates, and Rhizarians), Archaeplastida, Unikonta

Endosymbiosis

Relationship where one organism lives inside the cell or other cells of the host

Excavatas

Known for its cytoskeleton, have an excavated feeding groove on the side of the body

EXCAVATA: Diplomonads

Lack Plastids, modified mitochondria for anaerobic environments, mitochondria called mitosome, derive energy from anaerobic biochemical pathways, two equal sized nuclei and multiple flagella. (Typically parasites)

EXCAVATA: Parabasalids

Have a reduced mitochondria called a hydrogenosome for anaerobic respiration, lack plastids, can be parasites as well

EXCAVATA: Euglenozoans

Diverse clade that includes predatory heterotrophs, photosynthetic autotrophs, mixotrophs, and parasites. Most known for the spiral or crystalline rods in the flagella

Kinetoplastids

Have a single mitochondrion with an organized mass of DNA called a kinetoplast, Free-living species and are consumers of prokaryotes, over generations makes a new molecular structure to remain in similar hosts and evade the immune system of the host

Kinetoplast

Organized mass of DNA found in a kinetoplastid

Diplomonad Mitochondria is called a

Mitosome

Parabasalid Mitochondria

hydrogenosome

Euglenid

Have one or two flagella from a pocket extending from a pocket of a cell, they can be autotrophic or heterotrophic depending on environment

SAR (Stramenopiles, alveolates, and rhizarians)

Name for the most controversial group

Stramenopiles

Photosynthetic organisms, Most have hairy flagellates, include diatoms, gold/brown algae

Stramenopiles: Diatoms

Unicellular algae with a unique two part glass like wall of silicon dioxide

Major component of phytoplankton and are highly diverse

Will bloom and die, sequestering carbon from the atmosphere onto the ocean floor

Stamenopiles: Brown Algae

Largest and most complex algae, All are multicellular and live in marine water, includes seaweeds, known for plantlike structures like the root holdfast, and a stem like stipe which supports leaflike blades, lack true organs and tissues

Alveolates

Membrane enclosed sacs (alveoli) just under the plasma membrane

Include: Dino flagellates, apicomplexans, ciliates

Alveolates: Dinoflagellates

2 flagella, and each cell is reinforced by a cellulose plate, abundant components of phytoplankton, photo/hetero/mixotrophs (known for the red tide blooms)

Alveolates: Apicomplexans

apicomplexans are typically parasites, use infectious sporozoites to penetrate host cells, life cycles typically require 2 different hosts to complete, like plasmodium in humans and mosquitoes leading to malaria

Alveolates: Ciliates

Known for ciliated cells to move and feed, most commonly are bacterias or protists, two different nuclei, usually have genetic conjugation which two individuals exchange haploid micronuclei (sexual process)

Conjugation

A sexual process where two individuals exchange haploid micronuclei

Rhizarians

Mostly amoebas, use pseudopodia, extensions of cytoplasm and the cell, notably different than amoebas by having threadlike pseudopodia

Rhizarians: Radiolarians

Mostly marine protists, have delicate symmetrical internal silica skeletons, Pseudopodia reinforced by microtubules, cytoplasm covering the microtubules engulf prey that get attached to the pseudopodia

Rhizarians: Foramineferans

Porous shells called tests, made of calcium carbonate, Have pseudopodia that extend through pores, have photosynthetic algae

Archaeplastida

Hold algae’s and traditional plants

Red Algae

Have an accessory pigment called phycoerythrin, which masks green of chlorophyll making it red, usually multicellular, largest are seaweeds

Green Algae

NAmed for the green from chloroplasts, Plants and green algae closely related, two types:

Charophytes - more related to plants

Chlorophytes - sometimes symbionts with lichens and found in large amounts of visible radiation/light

Can form colonies, has true multicellular bodies, repeated division of nuclei with no cytoplasm divisions

Unikonta

Animals, fungi, some protists, unclear whether come from Otgher eukaryotes relatively early or late

Amoebozoans

Lobe or tube shaped, rather than threadlike pseudopodia

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Amoebaozoans: Slime Molds

Once thought to be fungi, Are similar due to convergent evolution, slime molds have two lineages either plasmodial slime molds: unicellular feeding mass, or in the fruiting body stage

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Amoebozoans: Tubulinds

Lobe/Tube Shaped pseudopodia, common unicellular Protists, Heterotrophic typically and seek other protists

Amoebazoans: Entamoebas

Parasites,

Symbiotic Protists

Benefit hosts, Dinoflagellates nourish reefs, some parasitic

Photosynthetic Producer Protists

Many protists are important autotrophs using CO2 to produce organic compounds, a Main Producer in the trophic group

Snake Plant

Fact: Most oxygen producing plant

Charophytes

Plants evolved from this, share with plants the rings of cellulose synthesizing proteins, flagellate sperm, formation of a phragmoplast

Sporopollenin

A Durable Polymer layer preventing zygotes from drying out, aids in the evolution of land plants as they benefitted from nutrient soils and CO2 in the atmosphere but with no water gave a lack of structural support

Embryophytes

Plants are known as

5 Key Traits for Plants (Absent in Charophytes)

Alternation of Generations, Multicellular and dependent embryos, Walled spores produced in sporangia, multicellular gametangia, Apical Meristems

Alternation of Generations

Plants alternate between two multicellular generations in a reproductive cycle, gametophyte generation is haploid and makes same gametes by mitosis, fusion of sperm and egg leads to diploid Sporophyte, which produces haploid spores by meiosis

Multicellular, dependent embryos

Diploid embryo is retained within the tissues of female gametophyte, nutrients transferred through placental transfer cells, Plants are embryophytes due to dependency of the embryo on the plant

Walled Spores Produced in Sporangia

Sporophytes produce spores in the sporangia, Diploid sporocytes undergo Meiosis to generate haploid spores, spore walls contain sporopollenin which makes them resistant to harsh environments

Sporopollenin

Found in spore walls and adds resistance to environmental conditions

Sporocytes

Diploid body cells

Multicellular Gametangia

Gametes are produced within gametangia, females are archegonia which produce a single non-motile egg, male gametangia are called antheridia and produce/release sperm

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Eggs are fertilized in a Archegonium

Apical Meristems

Plants sustain continual growth in length by repeated cell division within the apical meristems

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Cells from the meristems differentiate into other tissues

Other Derived Plant Traits

Cuticle - waxy covering

Stomata and Guard Cells - specialized gas exchange cells

When did Plants arrive in the Fossil Record"?

\~ 470 MYA found in rocks and other structures

Vascularized Tissues

Cells joined into tubes to transport water and other nutrients

Nonvascular plants

Called Bryophytes, and do not form a clade inside a phylogenetic tree

Angiosperms known for?

Being the flowering plants and having the most species around 250000

Seedless Vascular Plants: Lycophytes

Club Mosses

Seedless Vascular Plants: Monilophytes:

Ferns and the relatives

Seed \`

An embryo and its nutrients surrounded by a protective coat

Seeded Vascular Plants: Gymnosperms

Naked seeds that have no chambers

Seeded Vascular Plants: Angiosperms

Enclosed seeds where seeds develop inside chambers that originate within flowers

Bryophytes (nonvascular plants)

Represented today by three phyla of small, herbaceous plants such as:

Liverworts

Mosses

Hornworts

All are among the common ancestor of land plants

Bryophytes Gametophytes

In all bryophyte phyla, gametophytes are largert and live longer than sporophytes,

height of gametophytes constrained by lack of vascular tissues, Rhizoids anchor Gametophytes to substrates,

mature gametophytes have flagellated sperm and use their archegonium to fertilize eggs,

can reproduce in water with sperm or reproduce asexually

Rhizoids

Anchor gametophytes to substrate

Bryophytes Sporophytes

Never live independently of the gametophyte, Smallest and simplest sporophytes of all extant plant groups, have a foot, seta, a capsule which can discharge spores

Peat moss

Dead organic material, peat can be used for scotch and fuel, Has a lot of carbon inside, has a typical low temps, pH, and oxygen levels

Vascular Plant Traits

Life cycles with dominant sporophytes, vascular tissues called xylem and phloem, well-developed roots and leaves, spore bearing leaves called sporophylls

Traits: Life cycles with Dominant sporophytes

Sporophytes in are largely more complex in vascular plants

Traits: Xylem and Phloem

Two Types of Vascular Tissues

Xylem - Water and Minerals

Phloem - food

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Xylem uses tube shaped cells called tracheids, and water cells strengthened by lignin and provide structural support

Phloem has cells that are arranged into tubes that distributes sugars, amino acids, and other organic products

Traits: Evolution of Roots

Roots anchor plants, enable the ability of vascular plants to absorb and extract water/nutrients, thought to have evolved from stems

Traits: Evolution of Leaves

LEaves are organs that increase the surface area of vascular plants, maximizing photosynthesis. Categorized as Micro or Megaphylls. Micro only having a single vein in small leaves and Mega having large leaves with higher vascular systems

Sporophylls

Modified leaves with sporangia

Sori

Sporangia clusters on sporophyll undersides

Strobili

Cone like structures formed from groups of sporophylls

Homosporous

Most seedless vascular plants are homosporous, producing one type of spore that develops into a bisexual gametophyte

All seed plants, and some Seedless vascular plants are heterospores

Heterosporous species produce megaspores

Give rise to female gametophytes, and microspores, which give rise to male gametophytes

Seedless Vascular Plants: Lycophyta

Small herbaceous plants, club mosses, spike mosses, and quillworts

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Club and Spike are not true mosses

Seedless Vascular Plants: Monilophyta

Some of the most widespread plants, Notably ferns

Seed Plants believed to have originated

360 million years ago

Shared characters of seed plants

Reduced gametophytes, heterospory, ovules, pollen

Reduced Gametophytes

gametophytes are microscopic, develop within walls of spores that are retained within tissues of the parent, gains nutrients from the parent and is protected

Heterospory

homospores Made one kind of spore, usually a bisexual gametophyte

Heterospory produce two types of spores

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Megasporangia produce megaspores that give rise to female gametophytes (Produced on Megasporophylls)

Microsporangia produce microspores that give rise to male gametophytes (Produced Microsporophylls)

Ovules and production of Eggs

An Ovule consists of a megasporangium, megaspore and one or more protective pieces

Gymnosperm megasporangia have one protective integument

Angiosperm megasporangia usually have two integuments

Pollen and Production of Sperm

Microspore develops into a pollen grain that consists the male gametophyte enclosed within the pollen wall

Pollination is the transfer of pollen to the part of a seed plant containing the ovules

Germinated pollen grain produces a pollen tube that discharges sperm into the female gametophyte within the ovule

Pollen replaces water and gets rid of use of water for sperm distribution

Seeds Advantages

Can remain dormant for a long time, supply of stored food, can be transported a lot easier

Gymnosperm Lifestyle

3 Key: Miniaturization of their gametophytes, production of seeds, transfer of sperm to ovules

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Male Pollen cones are small and consist of modified leaves

Female ovulates are larger and consists of both modified leaves and stem tissues

Gymnosperms

Appear around 305 million years ago, drier conditions led to favorability

Phyla of Gymnosperms

Cycadophyta: Cycads

Ginkgophyta: One living

Gnetophyta: Three Genera: Gnetum, Ephedra, and Welwitschia

Coniferophyta: common things like pine, fir, and redwood

Cycadophyta

Individuals have large cones and palm like leaves, has flagellated sperm, and thrived during the Mesozoic era

Ginkgophyta

Phylum consists of a single living species Ginkgo biloba

Also has flagellated sperm, high tolerance to air pollution

Gnetophyta

Species vary in appearance and can be in multiple different ecosystems

Coniferophyta

Phylum is the largest gymnosperm, mostly woody cones, can photosynthesize all year round

Angiosperms Characteristics

Flowers and Fruits!

Flowers

Meant for sexual reproduction, can be animal pollinated or wind pollinated, a flower is a specialized shoot with up to four types of modified leaves

Types of modified flower leaves

Sepals - enclose the flower

Petals - Bright colored to attract pollinators

Stamens - male reproductive organ | also have a stalk called an anther, microspores which are produced in the anther develop into pollen grains

Carpels - female reproductive organ | Ovary at the base of a style leading up to a sticky stigma where pollen is received - pistil is a single or two fused carpels

Monoecious v. Dioecious

Monoecious is a normal complete flower

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Dioecious is an incomplete flower, missing one of the sexes

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Gynoecious flower is an incomplete flower that only has ovules

Radial Symmetry

Any imaginary line through the central, axis divides the flower divides into two equal parts

Bilateral Symmetry

A flower can only be divided into two separate parts and typically has distinctive right/left sides

Fruits

Formed from a thickened ovary wall, fruits protect seeds and aid in their dispersal, mature fruits can be dry or fleshy, seeds can be carried by adaptations help disperse seeds

Seed Dispersal

View Image

Angiosperm Life Cycle

Flower of the sporophyte is composed of both male and female structures, male gametophytes are contained within pollen grains, female gametophyte or embryo sac develops within an ovule contained within an ovary at base of the stigma.

Cross Pollination

Flowers ensure for different plants of the same species