MIDTERM EXAM #2 Flashcards
what is the definition of plant reproduction?
the formation of new individuals or the production of new members of a population from existing members. many also involve growth processes that result in the persistence of an individual, although in a new location.
what is the definition of plant asexual reproduction?
reproduction where a plant replicates itself without the involvement of meiosis or fertilization.
asexual reproduction is a product of ______ which is cell division producing __ daughter cells each with the (same or different) number of chromosomes as the parental cell.
mitosis.
2
the same
true or false: asexual reproduction in plants is very common
true. it often involves normal growth and ecological processes that result in the production of an independent plant
what are examples of asexual reproduction in plants?
-stoloniferous
-adventitious
-totipotency
-production of plantlets
what is stoloniferous/rhizomatous/spreading growth?
laterally growing stems that produce roots at nodes and may become independent plants over time
what are examples of stoloniferous growth?
-caespitose grasses
-plantlets (pups or suckers)
-tubers
-corms
-bulbs
what are plantlets?
buds at the base of a plant that develop comparitvely quickly into an entire plant. very common in agaves. grow from rhizomes or basal buds.
what are tubers?
typically a thickened rhizome or stolon (stem tissue). (potatoes are an example of)
tubers are a ______ ______ that seems to allow a plant to survive a period of _____ environmental conditions in a semi-protected state.
storage organ
harsh
what are corms?
short, vertical and thickened underground stem (stem tissue). storage tissue that may produce a new individual
what are bulbs?
underground vertical shoot with overlapping leaves modified for energy storage. (unions and garlic).
what is caespitose grass?
grass that grows in dense tufts and will produce new stems or tillers from buds at the base of the plant. commonly called bunchgrasses.
what is a tiller?
individual leaf and stem structure
caespitose grasses form a _____-_____ structure and successive ____ of _____ form outwards and create ____ as old tillers die. this type of movement is called _________
ring-like
rings of tillers
rings
spreading
what is king clone?
a ring formation of creosote bush that is ~21 meters in diameter at max. point
what is adventitious asexual reproduction and what is an example of this?
appearing in an abnormal or unusual position.
ex) formation of roots on non-root organs
what is totipotency (asexual reproduction)?
the ability of a single cell to produce specialized cells of many types given the correct circumstances. a cell is able to re-differentiate into an entirely different cell or organ type
the production of _______ from flowers (asexually) is common in agaves. Agaves are ______: they flower once and then die. the _____ may form in axis of floral bracts (modified leaves).
plantlets.
monocarpic.
plantlets
true or false: plantlets usually die when the mother plant dies
false; plantlets usually persist after mother plant dies and may establish as an independent plant.
what are the two organs related to plant sexual reproduction?
fruits and flowers
is meiosis sexual or asexual reproduction? what do you start and end with?
sexual reproduction. 1 parental cell (2n) –> 4 daughter cells (1n) (gametes).
what are plant gametes called?
pollen and egg cell (1n)
a gamete producing plant is called a _______ and a spore producing plant is called a _________
gametophyte (1n)
sporophyte (2n)
sporophytic meiosis produces what?
4 daughter cells
draw out or explain the cycle of the alternation of generations in plants
sporophyte (2n) –> meiosis –> spores (1n) –> gametophyte (1n) –> mitosis–> gametes (1n) –> fertilization –> zygote (2n) –> mitosis –> sporophyte (2n)
the transfer or movement of pollen grains is called ________
pollination. pollination does not equal fertilization
what are common examples of pollinators?
birds, insects, bats, and other animals. wind and water may also affect pollination
what two structures make up a stamen? what is a stamen associated with?
anther and filament.
associated with the microgametophyte
the ______ contain spores/pollen grains. when mature, the _____open up and release spores which travel to the top of the ______
anther
anthers
stigma
what is a microgametophyte?
a small gamete (pollen grain) producing plant with only 3 cells: a tube nucleus cell and two smaller sperm cells.
the microgametophyte grows down through the _______ and is a _____ _____
style
pollen tube or sperm delivery structure
what is a megagametophyte?
gamete producing plant structure that divides 3 times to create 8 nuclei. also known as an embryo sac.
describe the composition of the 8 nuclei that’re created in a megagametophyte
-1 gamete (egg cell)
-2 cells that’re close to the egg called synergids
-3 cells opposite from the egg called antipodal cells
-1 cell in the center called the center cell that has 2 nuclei that’re called polar nuclei.
as the _____ _____ goes through the style, it will reach and enter the __________ and will release its sperm nuclei.
pollen tube
megagametophyte
once the sperm has been released, one sperm cell will go the ____ ____ and fertilize it to create an _______ and the other sperm cell will fertilize the 2 polar nuclei in the _______ _____. this process is called what?
egg cell (gamete)
embryo
center cell
double fertilization
double fertilization results in the production of a nutritive tissue called _______ within the seed, which facilitates the production of a _____ ____ after double fertilization
endosperm
mature ovule
what is an ovule?
maternal tissue and megagametophyte that eventually form a seed. seeds are encased within the ovary wall, which will develop into a fruit.
a fruit is a _______ _______
mature ovary. flowers produce fruits that enclose seeds
true or false: the existence of seeds and fruits are one of the primary reasons why flowering plants dominate over non flowering plants.
true
what are the main roles of fruits?
-protect seeds
-effect seed dispersal
-provide nutrients for seeds, embryo, and seedlings
how are fruits classified?
dry vs. fleshy
dry: moisture content is below ~20% when seeds are mature
fleshy: high moisture content
dry fruits can also be classified into two categories:
indehiscent: doesn’t open at maturity
dehiscent: opens at maturity to release it’s contents
what are the 8 types of dry fruits?
-schizocarp
-caryopsis
-achene
-nut
-silique
-capsule
-legume
-follicle
what are the 3 types of fleshy fruits?
-berry
-pepo
-drupe
discuss all of the ways in which plants can move
pollen grains/spores can move via wind, animals, humans, and gravity.
plant bodies/vegetative structures can move via stoloniferous growth or being attached to animals
what is interspecific hybridization?
occurs when two different plant species are interbred to form a new species. is a relatively common process in plants and may be associated with polyploidization.
why is interspecific hybridization possible with plants in the wild?
it is possible with wild plants because the stigma is not a perfect barrier to “foreign” pollen and frequently pollen flows in the wind and can land anywhere.
why is hybridization considered to be possibly beneficial for plants?
it allows the hybrid plant to survive in a new type of environment, one intermediate between the two parental plants’ environments. most of the time the two parent plants can’t survive in the new environment
what is polyploidization?
polyploidization is an error in cell division that results in an increase in chromosome number. (polyploids: species with additional chromosome sets)
polyploidization in diploids:
-chromosomes (do or do not) pair consistently in diploid hybrid
-spores (are or are not) chromosomally balanced and (do or do not) develop normally
-do not
-are not
-do not
polyploidization in tetraploids (4n):
-chromosomes (do or do not) pair consistently in tetraploid hybrids
-spores (are or are not) chromosomally balanced and (do or do not) develop normally.
-do
-are
-do
tetraploid x diploid = ?
hexaploid (6n)
what is apomixis?
asexually produced seeds that are usually derived from diploid cells surrounding the embryo sac. (the egg cell doesn’t produce an embryo). common in the fam. Poaceae
during apomixis, does meiosis occur?
no, meiosis doesn’t occurs. The egg is diploid (2n), meaning that the seeds are genetically the same as the parental plant.
what is apomixis frequently associated with?
polyploidization
apomixis may be ___________, meaning that regular sexually produced seeds may also be produced
facultative
why is apomixis important in plant lives?
apomixis allows otherwise infertile plants to produce viable seeds
what is a gymnosperm?
naked seeded plants that produce seeds directly on the scales of cones. the ovules and seeds are exposed on the surface of the cones
what are the four common kinds of gymnosperms?
-conifers
-cycads
-ginkgo
-gnetophytes
what are conifers?
trees with needles or scale-like leaves. most numerous, widespread, and ecologically important gymnosperms (~630 species).
in conifers, are the male and female cones together or separate? if they’re separate, how do the two differ physically?
the male and female cones are separate but on the same plant. seed producing cones are greenish and larger than pollen producing cones.
what are cycads?
shrub and palm-like plants that’re found in tropical and subtropical regions. They’re dioecious, meaning they have separate plants for the production of microspores (pollen) and megaspores (eggs)
what is a ginkgo?
is a tree that was once native to China and has changed very little in the past 150 million years. Now is considered extinct outside of cultivation. (only consists of the species Ginkgo biloba)
ginkgo trees produce seeds with ______ _____ and are ________, meaning there are separate female and male plants.
fleshy coat.
dieocious
what are gnetophytes?
plants with very unusual morphology (~70 species). they reproduce similarly to angiosperms and are dieocious, meaning they have separate male and female plants
what is an example of a gnetophyte?
Welwitschia mirabilis
how do pollination to seed maturity rates differ in gymnosperms compared to angiosperms?
pollination to seed maturity may require up to 2 years to fully complete, which is much longer than angiosperms take.
what 4 main groups is diversity in the plant kingdom organized into?
-bryophytes
-seedless vascular plants
-gymnosperms
-angiosperms
what are bryophytes?
liverworts and mosses. plants that don’t produce seeds or have vascular tissue and must grow very close to the ground to obtain water. they cannot reproduce without the presence of free water
what type of tissue do bryophytes mostly consist of?
mostly gametophyte tissue
what are seedless vascular plants?
ferns; allows plant to grow up and away from the soil surface where free water could collect.
what type of tissue do ferns mostly consist of?
mostly sporophyte tissue
________ nominate in higher elevation climates with short growing season and where drought is quite common as is cold. their _____ are well adapted for moisture conservation.
gymnosperms
needles
what are angiosperms?
fruit and flower producing seeded vascular land plants
what is the largest family of angiosperms?
Asteraceae (more than 22,750 species)
are algae considered to be plants?
nahrr
what are some similarities and differences between the 4 large plant groups?
-bryophytes consist of mostly all gametophyte tissue vs. the other 3 are similar and are mostly sporophyte tissue
-angiosperms are the only group that produces flowers and fruits
-bryophytes don’t have vascular tissue and the other 3 do
-angiosperms and gymnosperms both produce seeds. bryophytes and ferns do not produce seeds
what is systematics?
scientific study of biological diversity
what is taxonomy?
the identifying, naming and classification of species
what is the hierarchical classification? (each level is called a taxon)
-kingdom
-division/phylum
-class
-order
-family
-genus
-species (specific epithet)
who was Carl Linnaeus and how did he contribute to plant classification?
Linnaeus was a Swedish naturalist who formalized and promoted the binomial system of nomenclature.
what is a herbarium?
collection of preserved plant specimens
a rule for naming: each species has a ___ _____ usually an herbarium specimen, which is designated by the person who originally named that species.
type specimen
what is phylogenetics?
the study of evolutionary relatedness among various groups of organisms
classification systems designed primarily as aids for identification and are based on few characters are known as ______ _______. these systems often do not reflect evolution
artificial systems
current classification systems called ______ _______ now strive to be an aid for identification in addition to actually reflecting evolutionary relationships
natural systems
in a natural system that reflects phylogeny, every taxon is _______, meaning it includes a single ancestor and all of its descendants.
monophyletic (cladogram’s can be used to depict this)
the agents of evolutionary change are a change in _____ traits of a population of organisms through ________ ________.
inherited (passed on from parents to offspring)
successive generations
what are the four main agents of evolutionary change?
1) mutations
2) gene flow
3) genetic drift
4) natural selection
what are mutations?
changes in cell’s DNA; caused by many factors inside and outside of the organism.
what are examples of things that may cause mutations inside and outside of the cell?
outside: UV light, toxins, and radiation
inside: errors in cell division in DNA
what is gene flow?
gene flow represents the movement of different individuals creating a change in the genetic distribution of the population. (migration)
how does gene flow occur in plants?
can occur through the movement of seeds, pollen or in some cases vegetative portions of the plant.
gene flow tends to be a ________ factor, meaning that 2 neighboring populations become more _______.
homogenizing
alike
what is the approximate distance to effectively isolate 2 populations (insect and wind pollinated)?
~300m for insect pollinated plants
~50m for wind pollinated plants
what is genetic drift?
genetic changes that over time result from the production of small, starting populations.
what is the Founder effect?
genetic difference in a population due to genetic drift. not associated with dispersal
what is the bottleneck effect?
genetic changes associated with drastic changes in a population size.
__________ is the result of natural selection
adaptation
what are adaptations?
evolutionary processes that produce organisms better suited for that environment
what is natural selection?
differential reproduction based on genetic constitution.
natural selection acts on ________ = genetic background and environmental effects
phenotype
describe the basic steps of natural selection//evolutionary change:
1) mutations create variation
2) unfavorable mutations are selected against and are less likely to reproduce
3) reproduction and mutations occur
4) favorable mutations are more likely to survive and reproduce
a species that occurs in different habitats may exhibit ________ _________ in each habitat
different phenotypes
what is an ecotype?
each group of genetically distinct populations adapted to specific environmental conditions
if differences between habitats are _______ (changing quickly), features of populations may differ ________
sharp
sharply
Clausen, Heisey, and Keck (1930/50) created an experimental method known as __________ ___________ to study plant evolution and natural selection
reciprocal transplantation
Clausen, Heisey, and Keck divided plants to create ______ and replanted them in _________ locations.
clones
different
what are the 3 common gardens called?
Standford, Mather, and Timberline
reciprocal transplantation lead to 3 conclusions:
-gradual evolution is brought about by small ______ _____
-natural selection is the main evolutionary process acting on ________ ______ within population
-evolutionary phenomena associated with macroevolution (speciation) are consistent with ___________________ mechanisms
genetic changes
random variation
microevolutionary (within individual species)
what is the biological species concept?
group of population whose members can interbreed with each other but cannot breed with members of other groups
what is the morphological species concept?
based solely on anatomical/morphological criteria
what is the phylogenetic species concept?
essentially based on reconstructions of evolutionary history (groups of organisms that have a high level of genetic similarity).
what is allopatric speciation?
involves the geographical separation of populations. (ex: mountain uplift: single species across entire range –> two taxa with isolated regions in range).
what is sympatric speciation?
occurs without geographic separation; often involves polyploidization (increase in chromosomes).
is sympatric speciation common in plants?
yes, very common in plants and much less common in other organisms.
according to smith, _______ ______ and __________ _________ lead to natural selection
genetic change and differential fertility
generally, what 4 things does soil provide plants with?
1) water
2) physical support
3) nutrients
4) suitable gaseous environment (sufficient oxygen to maintain the growth of plant structures such as roots or rhizomes).
soil formation is driven by _______ of ______ or _________ at the Earth’s surface.
weathering of rocks or minerals
what are the 4 main factors contributing to soil formation?
-minerals or rocks
-time
-biological materials (bacteria, algae, fungi, plants, animals, humans)
-physical processes (freezing, erosion, abrasion, thawing, air, water, gravity, volcanic activity, seismic activity)
soils are characterized by the appearance of their ________ which form as soil develops.
horizons (layers with specific traits)
describe the ___ horizon layer (aka the topsoil layer)
A horizon: layer with the most physical, biological, and chemical activity occurs. where humus accumulates. This horizon contains relatively high water holding capacity and serves as a great source of simple nutrient macromolecules.
what is humus?
relatively stable organic matter that has been eaten and metabolized by bacteria and fungi.
describe the __ horizon layer (aka the subsoil)
B horizon: region of deposition from the A horizon
describe the ___ horizon layer (aka the soil base)
C horizon: broken down minerals
what is bedrock?
unweathered rocks
____ of mineral particles determines the soil texture
size
what are the different sizes that mineral particles can be?
largest: gravel, sand, silt, clay: smallest
why is clay important for plant growth?
clay is important for plant growth because it has specific binding properties with ions that they may be in contact with
mineral particles may cluster with one another and other soil components to form soil _________. sometimes called ______.
structure
clods
the ways in which particles cluster together can affect what 3 main things?
-water movement
-infiltration
-root growth
soils contain _____ ______ occupied by air and water and mineral components; this has significant effects on ______ _______
pore space
plant growth
following wetting, soils ______ water even after ______ has removed loosely bound _______.
retain
gravity
water
when you have large soil particles, there are _____ ______ and water drains from the soil more _____ and ____ is available for plant growth
large pores
rapidly
less
when you have small soil particles, there are _____ _______ and they have better water holding properties against _____
small pores
gravity
how may botanists describe the different water holding “points” or capacities of different plants?
saturation: pore space is entirely filled with water
field capacity: pore space is half filled with water and the other half is air
wilting point: pore space is barely filled with water and contains mostly air.
soils with different _________ will have different _____ contents at each of these different points
texture
water
what may be used to depict the different water holding capacities of different soil textures?
an infiltration rate graph. on the x-axis, it is labeled time (min), on the y-axis it is labeled accumulated infiltration (mm). inside of the graph shows different lines based on their soil textures: clay, sand, and gravely/sandy
plants receive ________ ______ from soil which are typically ions that’re _______ in water
mineral nutrients
dissolvable
what does the soil solution contain?
mineral nutrient ions and soil particles
how many nutrients do plant require and what are the most important ones?
plants require 14 nutrients and the most important ones are nitrogen (1.5%), potassium (1%) and calcium (.5%)
