bio 102 semester 1 midterm! plants! keith!

Style

Leads from the stigma to the ovary at the base of the carpel.

Carpels

Make megaspores and their products, female gametophytes. On the top of a carpel is a sticky stigma that receives pollen. A style leads from the stigma to the ovary at the base of the carpel, the ovary contains one of more ovules. If fertilized, and ovule develops into a seed.

Polar nuclei

In angiosperms, the two nuclei of the central cell of the female gametophyte; they fuse with a sperm nucleus to form the triploid (3n) endosperm nucleus.

What roles do homology and homoplasy play in regards to taxonomy and phylogeny?

In cladistics, both homology and homoplasy are determined a posteriori with reference to a particular phylogeny that maximizes homology and minimizes homoplasy.

The rate of photorespiration will be highest when a plant:

is in a high temperature environment

Define the Morphological Species Concept.

It characterizes a species by body shape and other structural features

How does nonrandom mating affect genetic variation?

It does not directly affect allele frequencies, but usually prevents genetic equilibrium.

How does mutation affect genetic variation?

It introduces new genetic variation into population.

How does gene flow affect genetic variation?

It may introduce genetic variation from another population.

How does genetic drift affect genetic variation?

It reduces genetic variation, especially in small populations; can eliminate alleles.

Sporophyte

multicellular, diploid stage of the life-cycle. Increased importance of spore stage; greater spore production following mitotic growth of sporophyte

Identify the evolutionary mechanism(s) that, when acting as the only violation of the Hardy-Weinberg model, will result in two populations looking less similar for their allele frequencies at a locus.

mutation.

If a taxonomic group is understood to be paraphyletic, then this means

not all taxa descended from the most recent common ancestor are in the group.

The moss capsule is homologous to what structure found in conifer?

ovule.

If a taxonomic group is understood to be monophyletic, then this means

the taxonomic group is defined by one or more homologous similarities.

If a taxonomic group is understood to be polyphyletic, then this means

the taxonomic group is defined by one or more homoplastic similarities.

Stigma

the terminal portion of the gynoecium that has no epidermis and is meant to receive pollen.

Receptacle

the thickened part of a stem from which the flower organs grow. In some accessory fruits, for example in pomes or strawberries, the receptacle gives rise to the edible part of the fruit.

Endosperm

the tissue produced in the seeds of most flowering plants around the time of fertilization. It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein.

If analysis of data leads a biologist to conclude that red flower color in two plant species is a homoplastic similarity, then they are proposing

the two species had a most recent common ancestor without red flowers.

Hypocotyl

what appears to be the base stem under the spent withered cotyledons, and the shoot just above that is the epicotyl.

Synergid Cells

work together with egg and central cells to accomplish double fertilization.

The ancestral green algae from which the plant kingdom is thought to have evolved differ from the plant kingdom in that they have:

zygotic meiosis

The ancestral green algae, from which the plant kingdom is thought to have evolved, differ from the plant kingdom in that they have

zygotic meiosis.

A diploid population of 5,000 plants has the following number of individuals with each genotype at a locus with two alleles: 400 AA plants; 3,000 Aa plants; 1,600 aa plants. What is the frequency of the A allele?

0.38.

Generative Cell

A cell of the male gametophyte or pollen grain in seed plants that divides to give rise directly or indirectly to sperm.

Define phenetic.

Classification based on overall similarity usually in morphology or other observable traits.

Antipodal Cells

A group of cells, situated at the opposite end to the micropyle, in the mature embryo sac of flowering plants. They are very large and have highly endopolyploid nuclei.

Refer to CQ Key and answer questions 1-2.

(On your own.)

Megasporophyll

A leaflike structure that bears megasporangia.

Microsporophyll

A leaflike structure that bears microsporangia, such as those of in the strobili of lycophytes or in the male cones of conifers. The stamens of flowering plants are highly modified microsporophylls

Micropyle

A minute opening in the ovule of a seed plant through which the pollen tube usually enters.

What is the goal of phylogeny reconstruction?

A phylogeny is the evolutionary history of a group of entities. Given that this can only truly be known in exceptional circumstances, the main aim of phylogeny reconstruction is to describe evolutionary relationships in terms of relative recency of common ancestry.

Describe the relationship between taxonomy and phylogeny?

A phylogeny, or evolutionary tree, represents the evolutionary relationships among a set of organisms or groups of organisms, called taxa (singular: taxon). Taxonomists can use phylogeny to classify organisms into the appropriate taxonomic groups.

Carpel

A pistil may consist of a single free carpel, or be formed from a number of carpels that are fused. The pistil itself is formed from the stigma, style, and ovary.

Megasporangium

A plant structure in which megaspores are formed, such as those of the female cones of pines.

Filament

A stalk inside the Stamen

Describe basic life-cycle for the plant kingdom (alternation of generations).

All plants undergo a life cycle that takes them through both haploid and diploid generations. The multicellular diploid plant structure is called the sporophyte, which produces spores through meiotic (asexual) division. The multicellular haploid plant structure is called the gametophyte, which is formed from the spore and give rise to the haploid gametes. The fluctuation between these diploid and haploid stages that occurs in plants is called the alternation of generations. The way in which the alternation of generations occurs in plants depends on the type of plant.

Seed

Consists of an embryo and its food supply, surronded by a protective coat. When mature, seeds are dispersed from their parent by wind or other means. Because it nourishes and protects the embryo, yet can move away from the mother plant, a seed is analogous to a detachable and mobile version of a pregnant woman's womb.

Ovary

Contains one or more ovule to be fertilized. Ovules develop into seeds after fertilization, the all of the ovary thickens.

Fertilization

Fusion of gametes resulting in diploid zygotes, which divide by mitosis and form new sporophytes.In angiosperms, the sporophyte in the dominant generation.

Which statement correctly describes nuclear divisions for the sexual life-cycle of the Plant Kingdom?

Gametes result from mitosis, spores result from meiosis.

Petal

Has stamens and carpels inside. Interior to the sepals. These are brightly colored in most flowers and aid in attracting pollinators. Flowers that are wind pollinated lack brightly colored parts.

Flowering plants can proceed from pollination to seed dispersal more quickly than conifers due to which difference(s) in their alternation of generations?

Megagametophytes in flowering plants utilize triploid tissue produced post-fertilization to provide nutrition for the embryo, while conifers do not.

Moss and ferns differ in their Alternation of Generations in what manner?

Moss have a prominent gametophyte; ferns have a prominent sporophyte.

How does natural selection affect genetic variation?

One allele can replace another or allele variation can be preserved.

Ovule

Ovule literally means "small egg." In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: The integuments forming its outer layer, the nucellus (or megasporangium), and the megaspore-derived female gametophyte (or megagametophyte) in its center. The megagametophyte (also called embryo sac in flowering plants) produces the egg cell for fertilization. After fertilization, the ovule develops into a seed.

Stamen

Produce microspores that develop into pollen grains containing male gametophytes. A stamen consists of a stalk called the filament and a terminal sac, the anter, where pollen is produced.

Heterosporous

Producing two types of spores differing in size and sex, the male microspore and the female megaspore, which develop into separate male and female gametophytes. All seed-bearing plants, as well as some ferns and other seedless plants, are heterosporous

Examine the phylogeny below for photosynthetic organisms. Identify the statement that best describes the relationships shown among the five taxa.

See question 3.

How can we identify homologous characters?

Since a phylogenetic tree is a hypothesis about evolutionary relationships, we use characters that are reliable indicators of common ancestry to build that tree. We use homologous characters — characters in different organisms that are similar because they were inherited from a common ancestor that also had that character.

Tube Cell

That nucleus of a pollen grain believed to influence the growth and development of the pollen tube. Also known as tube nucleus.

Monocot

The Monocotyledonae comprise one-quarter of all flowering plant species. They include some of the largest and most familiar groups of plants, including lilies, orchids, agaves, palms, and grasses. Though often described as having a stereotype morphology, the monocots are actually quite diverse, ranging from tiny duckweeds to large palms and climbing vines.

Anther

The pollen-bearing part of the stamen.

What information is contained in the nodes and branches of a phylogeny?

The species or groups of interest are found at the tips of lines referred to as the tree's branches. The pattern in which the branches connect represents our understanding of how the species in the tree evolved from a series of common ancestors. Each branch point (also called an internal node) represents a divergence event, or splitting apart of a single group into two descendant groups. At each branch point lies the most recent common ancestor of all the groups descended from that branch point

Eudicot

The term "eudicots" has been widely adopted to refer to one of the two major clades of angiosperms, monocots being the other.

(True/False) Alternation of generations is seen in both vascular and non-vascular plants. Vascular plants contain a vascular tissue system that transports water and nutrients throughout the plant. Non-vascular plants do not have this type of system and require moist habitats for survival. Non-vascular plants include mosses, liverworts, and hornworts. These plants appear as green mats of vegetation with stalks protruding from them. The primary phase of the plant life cycle for non-vascular plants is the gametophyte generation. The gametophyte phase consists of green mossy vegetation, while the sporophyte phase consists of elongated stalks with a sporangium tip that encloses the spores.

True.

(True/False) The primary phase of the plant life cycle for vascular plants is the sporophtye generation. In vascular plants that do not produce seeds, such as ferns and horsetails, the sporophtye and gametophyte generations are independent. In ferns for example, the leafy fronds represent the mature diploid sporophyte generation. The sporangia on the undersides of the fronds produce the haploid spores, which germinate to form the haploid fern gametophytes (prothallia). These plants thrive in damp environments as water is required for the male sperm to swim toward and fertilize the female egg.

True.

(True/False) Vascular plants that produce seeds are not necessarily dependent upon moist environments to reproduce. The seeds protect the developing embryos. In both flowering plants and nonflowering plants (conifers), the gametophyte generation is totally dependent upon the dominant sporophyte generation for survival. In flowering plants, the reproductive structure is the flower. The flower produces both male microspores and female megaspores. The male microspores are contained within pollen and are produced in the plant stamen. They develop into the male gametes or sperm. The female megaspores are produced in the plant ovary. They develop into female gametes or eggs. During pollination, pollen is transferred via wind, insects or other animals to the female part of a flower. Male and female gametes unite in the ovary and develop into a seed, while the ovary forms the fruit. In conifers, pollen is produced in male cones and eggs are produced in female cones.

True.

Cotyledon

Upon germination, the cotyledon may become the embryonic first leaves of a seedling. The number of cotyledons present is one characteristic used by botanists to classify the flowering plants (angiosperm

Sepal

Usually green and enclose the flower before it opens

In a low-light environment, a shade-tolerant plant species might outperform other, light-tolerant plant species if the shade-tolerant species has:

a lower light compensation point

Microspore

a small spore as contrasted to the larger megaspore. This combination is found only in heterosperous organisms.

Microsporangium

a sporangium that produces spores that give rise to male gametophytes. In Gymnosperms and Angiosperms (Flowering plants), the microsporangium produce the microsporocyte, also known as the microspore mother cell, which then creates four microspores through meiosis. The microspores divide to create pollen grains.

Based on our current understanding of the phylogeny of the Plant Kingdom (i.e. the "embryophytes"), the character state "absence of (lignified) vascular tissue" that characterizes the paraphyletic "Non-Vascular Plants" group (liverworts, mosses, and hornworts) can be recognized as:

a symplesiomorphic character state

The Biological Species Concept provides a definition for identifying species that focuses on which evolutionary process(es):

absence of gene flow as a process leading to divergence

The Biological Species Concept provides a definition for identifying species that focuses on which evolutionary process(es)?

absence of gene flow as a process leading to divergence.

The conifer ovule is homologous to what structure found in moss?

capsule (2N).

Define cladistic.

classification based on common ancestry

The plant taxonomic group (phylum) with the largest number of species is

flowering plants.

Gametophyte

gametophyte is the multicellular structure, or phase, that is haploid, containing a single set of chromosomes: Produces male or female gametes through mitosis.

Self- Incompatibility

general name for several genetic mechanisms in angiosperms, which prevent self-fertilization and thus encourage outcrossing.

seeds

heterosporous condition in which spores are retained and seeds are dispersed. Dispersal unit is multicellular diploid early sporophyte instead of single-celled haploid spore; "pollination" eliminates need for free-water in the environment for sperm transport.

Pollination

in angiosperms and gymnosperms is the process that transfers pollen grains, which contain the male gametes (sperm) to where the female gamete(s) are contained within the carpel;[1] in gymnosperms the pollen is directly applied to the ovule itself. The receptive part of the carpel is called a stigma in the flowers of angiosperms. The receptive part of the gymnosperm ovule is called the micropyle.

The architecture of a plant's body can be altered by herbivore attack due to

interactions between meristems.

Radicle

is the first part of a seedling (a growing plant embryo) to emerge from the seed during the process of germination. The radicle is the embryonic root of the plant, and grows downward in the soil(The shoot emerges from the plumule). Above the radicle is the embryonic stem or hypocotyl, supporting the cotyledon(s).

Megaspore

large spore, germinates into a female (egg-producing) gametophyte, which is fertilized by sperm produced by the male gametophyte developing from the microspore.

Flowering plants can proceed from pollination to seed dispersal more quickly than conifers due to which difference(s) in their alternation of generations?

megagametophytes in flowering plants utilize triploid tissue produced post-fertilization to provide nutrition for the embryo, while conifers do not

Cladistics (parsimony-based) phylogeny reconstruction is a method that utilizes which optimality criterion(a)?

minimizing the number of homoplastic evolutionary events on the tree.

If you are able to observe gamete production occurring inside a conifer pollen grain, you will see

mitotic division of haploid cells.

If you were able to observe nuclear division occurring for cells inside a fern gametophyte, you would see:

mitotic divisions of haploid cells, fern gametophyte tissue is haploid

Cladistic and phenetic classifications of a single data set will be most dissimilar if

most similarities are due to shared ancestral traits.

Cladistic and phenetic classifications of a single data-set will be most dissimilar if

most similarities are due to shared ancestral traits.

Which group includes the greatest number of species for members of the Plant Kingdom?

plants that make embryos

Which group includes the greatest number of species for members of the Plant Kingdom?

plants that make embryos.

Sporophyte

produces spores (hence the name), by meiosis. These meiospores develop into a gametophyte. Both the spores and the resulting gametophyte are haploid, meaning they only have one set of homologous chromosomes. The mature gametophyte produces male or female gametes (or both) by mitosis. The fusion of male and female gametes produces a diploid zygote which develops into a new sporophyte. This cycle is known as alternation of generations or alternation of phases.

Homosporous

producing only one kind of spore

The Hardy-Weinberg equilibrium genotype frequencies of p2, 2pq, and q2 (for the AA, Aa, and aa genotypes, respectively) arise primarily as a result of

random mating from the gamete pool.

flowers

seed plants with abbreviated gametophytes, double-fertilization, and rapid reproduction

Heterospory

separate sporangia produce either megaspores or microspores. Specialization: resource allocation for differential roles of microgametophytes and megagametophytes (avoid intragametphytic selfing)

embryo

sporophyte begins development and gains protection/nutrition form parent gametophyte. Vulnerable stage (zygote/early sporophyte) establishes while attached to parent gametophyte

An infinitely large population has a locus that is affected by natural selection. A disfavored allele at low allele frequency will be eliminated most quickly if

the disfavored allele is dominant to the other allele.

Epicotyl

the embryonic shoot above the cotyledons. In most plants the epicotyl will eventually develop into the stem and the leaves of the plant

For most conifer species, a single sporophyte (tree) makes both megasporangia (in ovulate cones) and microsporangia (in staminate or pollen cones). These trees can make seeds using intergametophytic selfing, affecting the next generation's genotype frequencies in what way?:

the genotype frequency of heterozygotes is reduced by half

Using DNA barcodes to define species may lead to difficulty(ies) historically associated with the Morphological Species Concepts, which include(s)

the presence of within species variation, sibling species, and the impracticality of determing DNA barcodes for many organisms.

The heterosporous condition is always accompanied by:

the prevention of intragametophytic self-fertilization

The heterosporous condition is always accompanied by

the prevention of intragametophytic self-fertilization.

Double Fertilization

the process in angiosperms (flowering plants) during reproduction, in which two sperm nuclei from each pollen tube fertilise two cells in an ovary. The pollen grain adheres to the stigma of the carpel (female reproductive structure) and grows a pollen tube that penetrates the ovum through a tiny pore called a micropyle. Two sperm cells are released into the ovary through this tube. One of the two sperm cells fertilises the egg cell (at the bottom of the ovule near the micropyle), forming a diploid (2n) zygote. The other sperm cell fuses with two haploid polar nuclei (contained in the central cell) in the centre of the embryo sac (or ovule). The resulting cell is triploid (3n). This triploid cell divides through mitosis and forms the endosperm, a nutrient-rich tissue, inside the seed.

Germination, imbibition

the process whereby growth emerges from a period of dormancy. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm.

Fruit

the ripened ovaries of flowering plants. In many plant species, the fruit includes the ripened ovary and surrounding tissues. Fruits are the means by which flowering plants disseminate seeds, and the presence of seeds indicates that a structure is most likely a fruit, though not all seeds come from fruits.