Botany Exam 2 Questions

What are the synapomorphies for the embryophytes?

-Antheridia and archegonia with jacket cells -Retention of zygote and multicellular embryo within archegonium -Multicellular sporophyte and gametophyte -Multicellular sporangia with protective layer -Spores with sporopollenin -Apical growth

What are the characteristics of the bryophytes?

-Basics: paraphyletic, non-vascular plants, ca. 25,000 species, most live in wet environments, likely similar to earliest land plants -Structure: non-vascular, poikilohydric, thalloid, no true leaves, unbranched sporophyte, rhizoids, symbionts -Reproduction: gametophyte dominant, sporophyte depends on gametophyte, asexual reproduction, complex gametangia, single sporangium, spores with sporopollenin

What characteristics do the Charophytes share with the land plants?

-Chlorophylls a and b -Starch -Structural similarities -Reproductive characteristics -Chemical similarities

What similarities does the Charophyte alga Coleochaete have with land plants?

-Structural: apical growth, tissue-level growth, cuticle, plasmodesmata, phragmoplast -Chemical: lignin, callose, sporopollenin -Reproductive: antheridia structure, sperm ultrastructure, zygote retention, oogamy

What are the ways the land plant ancestor probably overcame the difficulties involved in the colonization of land?

-UV radiation and desiccation: cuticle, sporopollenin for reproductive structures, protective cells around gametangia -Gas exchange: stomata -Water/nutrient uptake and transport: vascular tissues, absorptive structures, mutualistic fungi -Physical support: support tissues, lignin, anchorage structures

What are the trends in the alternation of generations life cycle as you move through the plant groups (i.e., from bryophytes to angiosperms)?

-gametophyte dominant--> sporophyte dominant -gametophyte gets smaller -sporophyte gets bigger -gametophyte more protected -no water needed for reproduction

What historical trends occurred during the development of taxonomy?

-gradual development of the "modern" hierarchy -gradual recognition of the major plant groups; discovery of plant "sex" and monocots vs. dicots, gymnosperm vs. angiosperm, etc. -gradual increase in the number of characters used -gradual changes in approaches/philosophies about classification as a process and a product

Sum up the life cycle of the Ascomycota, including important structures and the ploidy of each.

1. Hyphae (n+n, n) form an ascoma in which asci (2n)develop 2. Karyogamy occurs inside the asci 3. Meiosis takes place 4. Ascospores (n) form

Sum up the life cycle of the Zygomycota, including important structures and the ploidy of each.

1. Spores (n) from the sporangium (2n) make their way to another Zygomycote 2. A gametangia (n) forms and holds a zygospore (n) 3. The gametangia containing the zygospore is a young zygosporangium (2n) 4. The zygosporangium matures 5. Germination takes place 6. Meiosis occurs during germination 7. A new sporangium forms and releases spores

Sum up the life cycle of the Marchantiophyta, including important structures and the ploidy of each.

1. Spores (n) germinate 2. raindrops hit antheridial head, splashing drops containing sperm (n) out and onto archegonial head of archegoniophore, which contains archegonia (n) with eggs 3. fertilization occurs, forming zygote (2n) 4. embryo forms 5. young sporophyte containing sporogenous tissue (2n) grows within enlarged archegonium (calyptra) 6. meiosis takes place 7. mature sporophyte (2n) develops, grows archegonial heads with spores (n)

Sum up the life cycle of the Basidiomycota, including important structures and the ploidy of each.

1. The basidium forms and releases basidiospores (n) 2. Plasmogamy takes place within germinating basidiospores of primary mycelium (n) 3. Secondary mycelium forms (n+n) 4. Young basidioma with tertiary mycelium (n+n) forms 5. Karyogamy of a young basidium (2n) of the mycelium (n+n) takes place 6. Meiosis occurs 7. Basidiodpores (n) form on basidium

Sum up the life cycle of the Bryophyta, including important structures and the ploidy of each.

1. spores (n) released; germinate 2. bud forms 3. antheridia of antheridial head on male gametophyte (n) hit with raindrop 4. sperm (n) splash out onto archegonia of archegonial head on female gametophyte (n), reach egg (n) 5. fertilization 6. zygote (2n) forms within venter, becomes embryo 7. young sporophyte (2n) develops with calyptra 8. female gametophytes (n) mature 9. mature sporophytes (2n) develop within capsule (sporangium) 10. meiosis of sporogenous tissue (2n) within capsule takes place 11. operculum over peristome opens, releases spores (n)

What is a lichen and what play the roles of mycobiont and photobiont?

A lichen is a symbiotic relationship between a mycobiont fungus and a photobiont algae.

What are mycorrhizae and what benefits does each part get from their association?

A mycorrhizae is a symbiotic relationship between a mycobiont fungus and a photobiont plant root. The plant benefits because it receives micronutrients from the fungus and the fungus benefits because it receives carbohydrates from the plant.

How do asexual and sexual reproduction occur in the bryophytes?

Asexual occurs via gemmae and gemma cups. In sexual reproduction, the gametophyte is dominant, while the sporophyte depends on gametophyte.

What is asexual reproduction and what are some ways that plants can accomplish it?

Asexual reproduction does not involve meiosis or fertilization. It is also known as apomixis. The progeny is identical to the parent rather than have a mix of chromosomes from two different parents. Plants may accomplish this using stolons, rhizomes, root suckers, and leaves.

How does Ascomycota undergo asexual reproduction?

Asexual reproduction is done via conidia on conidiophores.

What are some of the difficulties involved in the colonization of land by photosynthetic organisms?

Difficulties mainly arose due to newfound exposure to air and no longer being surrounded by water. This main problem then involved issues with radiation, desiccation, gas exchange, water/nutrient uptake and transport, and physical support.

What are the differences between gametic, zygotic, and sporic meiosis/alternation of generations?

Gametic is different in that is has a short-lived, inconspicuous haploid generation with a conspicuous, free-living diploid generation. Zygotic is different in that it has a conspicuous, free-living haploid generation with a short-lived diploid generation. Sporic is different in that it has multicellular haploid and diploid generations, a gametophyte, a sporophyte, and spores.

What is the biological species concept?

It is the concept that defines a species as members of populations that actually or potentially interbreed in nature, not according to similarity of appearance. Although appearance is helpful in identifying species, it does not define species. It is based off of the notion that a species consists of populations of organisms that can reproduce with one another and that are reproductively isolated from other such populations.

What is sympatric speciation?

It is the process by which new species evolve from a single ancestral species while inhabiting the same geographic region. This involves polyploidy and nondisjunction. It is due to these reproductive forms of isolation such as auto and allopolyploidy that sympatric arises.

How does Zygomycota undergo asexual reproduction?

It undergoes asexual reproduction via the use of sporangia, by which it produces spores.

How are meiosis and fertilization related to haploid and diploid?

Meiosis produces haploid gametes with only a single set of unpaired chromosomes. Fertilization takes those haploid gametes produced by meiosis and unites them to form a diploid zygote with two complete sets of chromosomes, one from each of the gametes.

How are the concepts of meiosis, fertilization, and sexual reproduction related to the different types of life cycles?

Meiosis, fertilization, and sexual reproduction all take place in each of the life cycles. However, while each life cycle has these things in common, they are different depending upon when meiosis takes place. Also they may differ in their haploid and diploid generations.

What are the pros and cons of sexual reproduction?

Pros include increased diversity and adaptation. Also, plants may be bred with others to acquire desirable characteristics. Cons include limited number of offspring and a greater energy investment. Also, a "perfect" plant will not pass on its perfection in totality to its offspring.

What are the pros and cons of asexual reproduction?

Pros include number of offspring, which is greater, and energy investment, which is smaller. If a plant has desirable characteristics, they will continue to pass on to generation after generation. Cons include little variability or adaptation to the environment.

How do the Stramenopiles (Bacillariophycae and Phaeophyceae) differ from the Rhodophyta found in the Archaeplastida?

Rhodophyta has chlorophyll a and d, phycobilins, Floridean starch, and a cellulose cell wall (some have calcium carbonate).

What benefits does each part of the lichen get from their association?

The fungus benefits in that the algae produces food via photosynthesis. The algae benefits by being protected from the environment by the filaments of the fungus, which also gather moisture and nutrients from the environment, and (usually) provide an anchor to it.

What is the general life cycle of fungi and how do plasmogamy and karyogamy relate to the fungal life cycles?

The general life cycle is zygotic meiosis. Plasmogamy relates to this in that, during fertilization of sexual reproduction, it is when the cytoplasm of two parent cells fuse together without the fusion of their nuclei. Karyogamy occurs afterwards and is the subsequent fusion of those nuclei.

How are the hyphae of Basidiomycota different from those of both the Zygomycota and the Ascomycota?

The hyphae of the Basidiomycota are septate with clamp connections. These clamp connections are created to ensure each cell, or segment of hypha separated by septa (cross walls), receives a set of differing nuclei, which are obtained through mating of hyphae of differing sexual types. Basically, they are used to create genetic variation within the hypha, much like the mechanisms found in crozier during sexual reproduction.

How are the hyphae of the Ascomycota different from that of the Zygomycota?

The hyphae of the Zygomycota are aseptate, coenocytic hyphae. This means they are made up of a multinucleate, continuous mass of protoplasm enclosed by one cell wall. Aseptate means not divided into sections or compartments by septa. The Ascomycota hyphae have perforated septa.

How are the Chlorophytes and Charophytes similar?

These two are similar in that they both have chlorophyll a and b, two whiplash flagella, starch, and pectin/cellulose in their cell walls.

What are the similarities between gametic, zygotic, and sporic meiosis/alternation of generations?

They are all similar in meiosis and fertilization.

What are autopolyploidy and allopolyploidy and how do they relate to sympatric speciation?

They are both forms of polyploidy, the occurrence of more than two sets of chromosomes. Autopolyploidy is having polyploidy which is derived from the same species, while allopolyploidy is having polyploidy which is derived from different species. They both relate to sympatric speciation in that they cause it to occur, as they are both forms of reproductive isolation.

What does it mean that fungi are decomposers and how do fungi obtain their nutrients?

They are decomposers in that they break down organic matter, thereby returning organic materials to the soil. They are able to decompose many organic materials that other organisms can not, including cellulose and lignin. They may also be parasitic. This decomposition is thus where they obtain their nutrients from.

How is the morphological species concept used and what aspects of living organisms can make it difficult to use?

This concept is used to group or classify organisms based on morphological or physical appearance. This in itself is incredibly difficult to use efficiently, as looks are not a good basis to determine ancestral or familiar relationships off of. It simply does not work, as many organisms may appear physically similar, but could be totally unrelated on every other level due to things like convergent evolution, etc.

What synapomorphy groups the members of the Stramenopiles (Bacillariophycae and Phaeophyceae) together?

Tinsel flagella is the synapomorphy which groups these members together.

What are the differences between utilitarian, natural, and phylogenetic classifications of organisms?

Utilitarian, or artificial, classification is the same as the Linnaean system. This is a system of grouping unrelated plant species by a common criteria, particularly sexual characteristics. Natural classification reflects evolutionary relationships. It classifies organisms according to relationships based on descent from a common ancestor. Phylogenetic classification looks to organisms' evolutionary histories as a means of grouping them together.

What is the difference between endo- and ecto- mycorrhizae?

With endomycorrhizae, the hyphae of the fungus are present within the cell wall of cells in the plant root. With ectomycorrhizae, the fungus forms a sheath on the outside of the plant root; the fungus may enter the plant root, but the hyphae never penetrate the plant cell wall.

How are meiosis and fertilization related to sexual reproduction?

Without meiosis and fertilization, there would be no sexual reproduction. It would be asexual. Meiosis produces haploid gametes, then fertilization takes those gametes and produces diploid zygotes. In asexual reproduction, there is no meiosis or fertilization.

How do the mosses disperse their spores?

via the use of sporophyte capsules that "shoot" out spores upon opening of operculum