Biology 1112

Lecture Three

Slide 2 – Common terms and definitions - sporangium

Sporangium (sporangia) – is an organ containing and/or producing spores.

It is also defined as a protective layer of sterile cells surrounding haploidspores in a sporophyte (defined as a spore-case or a receptacle for spores).

Slide 3 – Common terms and definitions – Sporophyte and gametophyte

• Spore (zoospore) – an asexual reproductive cell that can develop into a free living organism

• Sporophyte – Diploid structure and is a spore producing stage of protests and/or some plant life cycle with each cell containing two complete sets of chromosomes

– It is also defined as the spore-producing individual or phase in the life cycle of a plant having alternation of generations

– The sporophyte develops from the union of two gametes, such as an egg fertilized by a sperm; in turn, the sporophyte forms spores that develop into gametophytes.

• Gametophyte – haploid, multicelled, gamete producing phase in life cycle of most plants.

– Gametophyte is a phase of an organism’s life cycles in which the gametes (e.g. egg and sperm) are produced.

– The gametophyte is haploid, that is, each cell contains a single complete set of chromosomes, and arises from the germination of a haploid spore.

Slide 4 – Common terms and definitions – hyphae and mycelium

Hypha (hyphae) – is composed of fine microfilaments usually consists of chitin. These structures are usually involved in absorption structure component of the mycelium

Mycelium – A multicellular structure that is formed by a mesh of branching hyphae

Slide 5 – Kingdom Protista

Slide 6 – General characteristics of protists

• Most organisms that belong to the Kingdom of Protista (or protests) are generally unicellular organism.

• Protists are eukaryotes and

have a nuclear envelope encircling their genetic materials.

• These eukaryotes have membrane bounded organelles within their cytoplasm.

• Protists have plant-like, fungal-like, and at times animal-like characteristics

• Some scientists believe they are the protists evolved into higher organisms. Paramecium

Slide 7 – Protists’ characteristics (movement)

Mobility – most protists utilizes either flagella, cilia,amoeboid-like (using pseudopods) for movement

Slide 8 – Protist characteristics (energy production/consumption)

• Food or energy production – protists could either utilize chloroplasts (autotrophic) for energy production, taking in (ingesting) organic substance via food vacuoles (heterotrophic), or possesses both the combined ability

Slide 9 – Protist characteristics (reproduction)

• Reproduction – they could reproduce either asexually or sexually. Sexual reproduction generally occurs when conditions are harsh and that genetic diversity may aid in the organism’s ability to survive

• Survival – when faced with harsh conditions, the protists develops many sporangia where spores are produced and released to propagate in many different locations where one of these locations may allow the ‘offspring’ of the protist to survive

• Furthermore, protists may also survive the onset of harsh environments by forming cysts

• A cyst is a dormant cell with a resistant outer covering, which allows it to survive harsh droughts, temperature changes and even digestive juices of the animal digestive tracts.

Slide10 – Importance of protists

• Some protists belong to a group of free-floating organisms know as planktons are photosynthesizes and they gives off oxygen

• These planktons provide food for other heterotrophic protists and animals

• Protists also form symbiotic relationships with corals and allow the corals to become photosynthetic

• A type of protists known as algae can provide valuable materials (e.g. agar) for medical or scientific research. Algae can processed to form fertilizers and can be harvested for algin – a pectin like substance that is added to ice cream, cheese to give it stable consistency

• Diatoms – a type of protist with its silicate based outer shell will accumulate on the bottom of the ocean. These diatoms are harvested and used as filtering agents, sound proofing materials and gentle abrasives

Slide 11 – Chytridiomycota

Chytrids (chytridiomycota) – chytrids are molds that predominantly exists in both marine and fresh water environments

Most of these organisms are saprobes – a type of heterotrophs that secrete digestive enzymes to break down organic substances in its immediate surroundings. Once the organic substance is broken down, chytrids than absorb the nutrients

Some Chytrids are parasites on living plants and animals (e.g. mosquito larvae, nematodes and liver flukes) Most of the chytrids are also known as decomposers which are responsible (generally) for breaking down dead materials

Chytrids have chitin strengthening their cell walls, and one subgroup (Hyphochytrids) have cellulose as well

Slide 12 – Chytridiomycota lifecycle of Allomyces – alternation of isomorphic generations

Slide 13 – Water molds (Oomycota)

Oomycota are saprobic decomposers that reside mostly in moist and/or aquatic habitats

Oomycota are previously grouped into Kingdom Fungi but now are placed in protests

There are about 475 species of Oomycota

Oomycota are commonly referred to as Oomycetes

Some oomycota are parasitic (e.g. blight of potatoes – Irish potato famine in 1845-1847)

They produce extensive mycelium and contain cellulose in their cell wall rather than chitin

They can reproduce sexually and asexually

Slide 14 – Lifecycle of Oomycota (Saprolegnia ) - alternation of heteromorphic generations

Slide 15 – Cellular slime molds (Acrasiomycota)

Cellular slime molds (Acasiomycota) - spend most of their lives as separate single-celled amoeboid protests

Cellular slime molds consists about 65 species

These free living amoeba like cells are phagocytic predators and feed off bacteria or decomposers who feeds off decaying leaves or bark

These amoeba like cells are haploid (n) containing a single nucleus

These organisms are similar to plants where they are rich in cellulose

Slide 16 – Reproductive cycle of cellular Slime Mold (Dictyostelium discoideum)

Slide 17 – Plasmodial slime molds

Plasmodial slime molds (Myxomycota) are composed of many single celled slime molds with no cellular boundaries which gives it the appearance of having thousands of nuclei

Plamsmodial slime molds consist of 450 speciesThey are formed when individual amoeboid like cells swarm together and fuse

There are no boundaries between the individual amoeboid-like cells therefore they are referred to as multinucleate plasmodium

The result is one large bag of cytoplasm with many nuclei with free floating cytoplasm also known as cytoplasmic streaming

These plasmodial slime molds are both predatory as well as decomposers where they ingest bacteria, fungal spores and dead leaves etc.

The plasmodial slime molds reproduce both sexually and asexually

Slide 18 – Reproductive cycle of plasmodial slime molds

Slide 19 – Binary fission - protozoan

Slide 20 - Protozoan cysts (Entamoeba histolytica - amebic dysentery)

Slide 21 – Amoeba-like movement

Slide 22 – Amoeboid protozoans (Sarcodines)

Slide 23 – Rhizopods – entamoeba histolytica

Slide 24 – Paramecium trichocysts

Slide 25 - Paramecium

Slide 26 – Protozoans conjugation

Slide 27 - Giardia lamblia - Giardiasis

Slide 28 - Trichomonas vaginalis

Slide 29 – African Sleeping Sickness

Slide 30 – Pneumoncystis carinii

Slide 31 – Malaria – plasmodium vivax

Slide 32 – General symptoms of Malaria

Common symptoms

1 Fever

2 Flu-like symptoms

3 Chills

4 Severe headaches

5 Arthralgia

6 Jaundice

7 Anemia

8 Vomiting

9 Convulsions

10 Bloody urine

11 Hepatomegaly

12 Spenomegaly

13 Coma

14 Death

Matured trophozoite and ruptured schizont in red blood cells

Slide 33 – Single cell algae - diatoms

Slide 34 – Multi-celled algae

Slide 35 – Zoospores – flagellated spores

Slide 36 – Isogamous – gametes of the same size and shape

Slide 37 – Oogamous – Sperm and egg

Slide 38 – Alternation of generation

Alternation of generation – the life cycle of the organism is alternating between haploid (1N) and diploid (2N).

There are two types of alternation of generations:

Slide 39 – Haplontic and Diplontic reproductive cycle

Haplontic reproductive cycle – the adult is haploid (1N)

Diplontic reproductive cycle – the adult is diploid (2N)

Slide 41 – Diatoms – phytoplankton

Slide 42 - Diatoms

• They are important part of the food source for both fresh water and marine organisms

• The diatom is composed of a box like structure where it is arranged in a two half structural system – a larger top half and a smaller lower half

• Outside of the cell wall of the diatom is a silicate compound similar to glass and are used for protection

• Diatoms lack flagella and are free-floating organisms

• Asexual reproduction – where the asexually reproduced half receives the top half of the “box” while the new “box” grows inside of the old one

- Because of the box within a box system of asexual reproduction, the new organisms are 30% smaller on average than the original.

• Sexual reproduction – (haplontic) diatoms produces oogamy (sperm and egg) while the sperm are flagellated

- The zygote (2n) grows and divides mitotically and produces diatoms of normal size

• Commercial benefits – The remains of diatoms with its silicate based outer shell will accumulate on the bottom of the ocean.

• This is harvested and is used as filtering agents, sound proofing materials and gentle abrasives

Slide 43 - Dinoflagellates

Slide 44 - Dinoflagellates

• If the cell wall is present, they are mostly composed of cellulose plates

• This type of organism possesses two flagella for mobility

• They contain both chlorophyll a and c and are also a part of the phytoplankton population within earth’s oceans

• Reproduction – Dinoflagellates proceed through mitosis (asexual reproduction a form of binary fission) nevertheless they have some significant differences in their process of mitosis

• The nuclei of the dinoflagellates are unlike those of any other organisms – the chromosomes lack any centromere and are permanently in condensed formation

• Even when the organism is proceeding through mitosis, the nucleolus and nucleus persist throughout cellular division

• Benefits – some dinoflagellates forms symbiotic relationships with corals and allow corals to become photosynthetic

• Commercial significance – Some dinoflagellates when their population increases may cause “red tide”

• These dinoflagellate produces a type of neurotoxin that causes paralysis in fish and could be accumulated in shellfish

• These shellfish, if consumed by humans, will cause paralysis of the respiratory tract and eventually death

Slide 44 – Red Tide

Slide 45 - Euglenoids

Slide 46 - Euglenoids

– One-third of this group is photosynthetic (photoautotrophs) while the remaining are heterotrophs (ingesting or absorb organic materials for food).

– They contain two flagella where one is longer than the other

– They have a pyrenoid – which is centers of carbon dioxide fixation

– Through carbon dioxide fixation they produces a type of carbohydrate known as paramylon for storage and utilization

– They have chloroplasts containing chlorophylls a and b and various carotinoids

– Euglenoids also have an eyespot, which contains photoreceptors for detecting light.

– Reproduction – mitosis (asexual) in a form called longitudinal cell division

Slide 47 – Green algae - chlorophyta

Slide 48 - Chlorophyta

– This unicellular organism and/or multicellular organism comprise of 8000 different species

– They live in oceans, fresh water or even on land where abundance of moisture is available.

– Green algae form symbiotic relationship with fungi, plants and even animals.

– They are believed to be closely related to plants since they possess cell walls that contain cellulose and have chlorophyll a and b and stores starch inside the chloroplast, which is similar to that of plants.

– These organisms release oxygen as a by-product just like plants

– Sexual reproduction – Haplontic cycle

Slide 49 – Flagellated green algae

This type of protist has a definite cell wall and a large cup-shaped chloroplast that contain a pyrenoid (where starch is synthesized)

This algae also contain a stigma or eye spot to identify where the light source are located and direct the two whip-like flagella towards the light source

Sexual reproduction – Haplontic cycle

Pyrenoid

Slide 50 – Filamentous green algae

Slide 51 - Spiralgyra

These haploid organisms are found in pond surfaces and streams

These algae contain a ribbon like spiral chloroplast. Asexual reproduction - when conditions are favorable they produce asexually forming zoospores (flagellated spores - isogametes) that are similar to the parent cell

These spores are haploid (1n) and develop into a mature adult

Conjugation - Sexual reproduction –– occurs during winter and harsh conditions

- Temporary union that occurs between two cells align each other parallel to one another and forming a temporary connection

- The entire content of one cell is subsequently transferred from one cell to another forming a diploid organism or a zygote

- After the favorable conditions returns the cell undergoes meiosis and produces four new haploid organisms

Oogamy - sexual reproduction – When conditions are unfavorable, the algae produces an egg and a motile sperm for this form of sexual reproduction

Slide 52 – Multicellular green algae - ulva

Slide 53 – Colonial Green Algae

Commonly known as a volvox – these are a loose connection of independent cells that resulted in the formation of a colony.

The cells within this colony are specialized in their functions Some cells are for sexual reproduction only while others are for mobility by coordinating their flagella in a unidirectional manner The Volvox’s appearance is that of a hollow ball and can proceed in asexual and sexual (oogamy) reproduction During asexual reproduction a smaller daughter colony is formed within the hollow space within the Volvox, which later escapes the parent cell by dissolving away a portion of the parental colony.

Sexual reproduction – a slight variation of Haplontic cycle

Slide 54 – Red algae

Slide 55 – Red algae

– A type of marine seaweeds – Known to grow in warmer of tropical seawaters

– Some red algae are simple filaments while others are complexly branched having feathery or leafy appearance.

– They contain cellulose and calcium carbonate within their cell walls and have both chlorophyll a and chlorophyll d (not seen in plants)

– They reserve their food source in a form of sugar that resembles glycogen (animal sugar), which is in turn called floridean starch

– Sexual reproduction – their reproductive cycle are still mostly a mystery nevertheless, they do have an oogamy generation which sperm and egg are produced

• The sperm of red algae are non-flagellated and are unique in this manner

– Commercial benefits – they produce agar for scientific usage

Slide 56 – Brown algae

Slide 57 – Brown algae

– Another type of marine seaweeds – more temperate to cold seas (California coast etc.)

– This type of algae has chlorophyll a and chlorophyll c in their chloroplasts and a type of carotinoid called fucoxanthin.

– Their reserve food source is in the form laminarin (a type of sugar)

– These algae are resistant to dry out usually since their cells wall contain a mucilaginous, water retaining material

– Sexual reproduction – Diplontic cycle

– Commercial benefits – they can produce fertilizers and can be harvested for algin – a pectin like substance that is added to ice cream, cheese to give it stable consistency

Slide 2 - Fungi

Slide 3 – General characteristics of fungi

Fungi have the following characteristics:

• They are eukaryotic organisms

• Most are multicellular eukaryotic organisms

• Some are unicellular organisms – yeast is the prime example

• They are heterotrophs that consume organic matter

• They do not consume their food source but they absorb nutrients

– Fungus spew out digestive enzymes and dissolve the organic matter externally and then they absorb the food source

• Most fungi are saprotrophic that decomposes organic matters such as leaves or dead bodies

• Some fungi are parasitic

• Some fungi form mutualistic relationship with roots of seed plants where they acquire inorganic nutrients for plants and in return they are fed organic matters by the plant itself

Slide 4 – Mycelium and hyphae of the fungi

Mycelium

Hyphae

Slide 5 – Function of hyphae

– The branching hyphae provide large surface area for the fungi

– The large surface area allows the fungi to increase its absorption rate/amount

– The tips of the hyphae grows while the bundle of hyphae (known as mycelium) absorbs and pass nutrients to the growing tips

– Reproduction occurs when a specific part of the mycelium becomes a reproductive structure while the remaining mycelium provides nutrients it needs

– Fungi cells contains no chloroplasts

– Fungi cells contains a cell wall that is constructed out of chitin (similar to the exoskeleton of a shrimp or crab) and not cellulose

– The storage sugar of the fungi is glycogen and not starch - similar to animals

– Fungi are immobile throughout their life cycles (no flagellated sperm etc.)

Slide 6 – Septae and nonseptate fungi

Septa

Septae fungi Nonseptae fungi

Slide 7 – Fungi – sexual reproduction

Slide 8 – dikaryotic – sexual reproduction of fungi (n + n)

Slide 9 – zygospore fungi

Characteristics of a zygospore fungi (bread mold):

- A horizontal hyphae called a stolon exist on the surface of the bread and eventually

grows into the bread itself.

- Mycelium forms through aggregation of hyphae while rhizoids grows out and anchors the mycelium

- Mycelium carries out external digestion and food absorption

- During asexual reproduction a sporangiophore grows out of the mycelium and at the tip of this structure

a sporangium is formed.

- Sporangium produces haploid spores and are subsequently released into the

environment

Slide 10 – sac fungi - truffles

Sac Fungi – (~30,000 species) they are saprotrophs that digests materials that are otherwise not easily digested (e.g. cellulose, lignin or collagen etc.)

- Truffles belong to this group of fungi

- Yeast is another example but it is

an unicellular sac fungi

Slide 11 – club fungi – common mushrooms

Ergot on wheat

Slide 12 – imperfect fungi - Penicillin notatum

Slide 13 – Magic mushrooms

Slide 14 – deadly mushrooms – Destroying Angel

The structure of alpha-amanitin

Slide 15 – Origin of fossil fuel

Slide 16 – Plant cuticle

Slide 17 – Stomata (stomates)

Slide 18 – Carotinoids (e.g. ß - Carotene)

Slide 19 – Plant sex organs (gametangia)

Slide 20 – Sporophyte and gametophyte generations of plants

Slide 21 – vascular vs. nonvascular plants

Slide 22 – Characteristics of nonvascular plants

Non-vascular plants has the following

characteristics:• Gametophyte is the

dominant generation in non-vascular plants

• The flagellated sperm swim to the egg (located in the archegonia) in a water fill medium

• Due to the flagellated sperm, the non-vascular plants usually require a moist environment.

Slide 23 - Bryophytes

Bryophytes (non-vascular plants) are mosses,liverworts and hornworts

• They do not have internal vascular structures such as xylem or phloem to transport water and nutrients (dissolved sugars and ions) respectively

• They do have leafy and stem like structures that makes up their body

• Bryophytes are capable of being dried out (proceed in a form of dormancy) and still revive itself after the absorption of water

• They have rhizoids that are very similar to roots but again do not have internal vascular structures nevertheless performs anchoring and absorption duties

Slide 24 – Non-vascular plants - hornworts

Hornworts – are usually found in tropical forests, along streams, and in disturbed fields around the world Most species are small and unassuming greasy blue-green patches

Hornworts will generally have a single large chloroplast per cell.

Slide 25 – non-vascular plants - liverworts

Liverworts – all liverworts has the following traits:

A flattened thallus or a leafy body or a lobed thallus or body

Each thallus has a smooth upper surface and a lower surface that possesses numerous rhizoids – hair or root like projections into the soil.

Liverworts are capable of sexual and asexual reproduction

Sexual reproduction depends on the disk-headed stalks that bear antheridia – where the flagellated sperm are produced.

Eggs are produced on the umbrella-headed stalks that bears the archegonia.

After fertilization a tiny sporophyte composed of a foot, short stalk and capsule appears. Windblown spores are produced within the capsule

Slide 26 – non-vascular plants - mosses

Mosses – Mosses can be found from the Artic through the Antarctic although they prefer damp temperate environments. Mosses have the following traits:

Mosses have usually a leafy shoot

Mosses can contain a tremendous amount of water and can become dormant when the environment becomes too dry

Mosses can reproduce asexually by fragmentation – just about any part of the plant can produce leafy shoots

This form of reproduction is most common in desert, artic and Antarctic regions

Mosses have Rhizoids those functions as an anchor. Rhizoids also contain the antheridia and archegonia

The antheridia consist of a short stalk, an outer layer of non-reproductive cells used for protection and an inner mass of cells that becomes the flagellated sperm

Slide 27 – Vascular plants

Slide 28 – vascular plants

Slide 29 – Anatomy of roots

Slide 30 – Anatomy of a plant stem

Slide 31 – Anatomy of a vascular leaf

Slide 32 – Microgametophyte (e.g. pollen)

Slide 33 - Megagametophyte

Slide 34 - horsetail

Slide 35 – Whisk fern

Slide 36 – Ferns – fiddle head and fronds

Slide 37 – Lifecycle of ferns

Slide 38 – Gymnosperm lifecycle

Slide 39 – conifers - Redwood (Sequoia sempervirens)

Slide 40 - cycads

Slide 41 – Ginkgo trees

Slide 42 - Gnetophytes

Slide 43 - Dicot stems

Slide 44 – monocot stems

Slide 45 – Lifecycle of an Angiosperm

Slide 46 – Anatomy of a flower