Exam 2 Flashcards
(109 cards)
1
Q
Modular Growth
A
growth that occurs by adding repeated units (modules to the body). lends to the plasticity of the plant. Plants can survive losing large portion of their shoot to herbivory because they have these repeating modules
2
Q
What is a meristem
A
collection of undifferentiated cells, lack specialized function
3
Q
What are the different types of meristems?
A
Apical, Intercalary, Axillary, root apical, inflorescence
4
Q
What is apical meristem?
A
undifferentiated tissue at the tip of a growing stem or branch. Production of new cells behind the apical meristem allows the stem to grow. Cells differentiate to perform different functions.
Also include nodes/internodes
5
Q
What is a node (apical meristem)
A
point of cell proliferation where leaves or flowers will develop. Often visible as a bump. Primordium (bud) develops here.
6
Q
What is an internode
A
stem between nodes. Rosette plants (ex: cabbage) have very short internodes.
7
Q
What is intercalaray meristem
A
group of cells generated at a node. These cells when activated allow the internodes to keep elongating. Make it possible for plants to regrow after fire or after leaves are eaten by herbivores.
8
Q
Axillary meristem
A
meristem located at each node on the leaf axil (where leaf and stem join). Produces axillary bud. Inactive when apical meristem is intact.
9
Q
Root apical meristem
A
control root growth. Located behind the root cap (loosely held cells that slough off as the root extends through the soil). Roots do not have nodes or internodes. Roots branch when special differentiated cells resume active division. Each new branch has its own meristem.
10
Q
Inflorescence
A
floral structures of a plant. These develop from meristems (apical and axillary) that cease to be meristems and instead produce floral structures.
11
Q
What is apical dominance?
A
axillary meristems are inactive when the apical meristem is intact. Apical meristem produces hormones (ex: auxins) that inhibit the proliferation of cells in the axillary meristems.
12
Q
What is Primary growth?
A
increasing in size by growth of apical (and axillary?) meristems.
13
Q
Secondary growth
A
increasing girth by producing woody tissue (secondary xylem). All perennial gymnosperms and most perennial angiosperms.
As stems mature the vascular bundles grow together and coalesce to form a sheath around the inner part of the stem. Between xylem and phloem (just under phloem and epidermis) the vascular cambium forms. Vascular cambium extends much the length of the stem.
14
Q
What is clonal growth?
A
vegetative reproduction or the reproduction of a new ramet? Example of apoximis (asexual reproduction). Produces a collection of new ramets that are integrated (at least initially).
15
Q
What are the various forms of clonal growth?
A
Stolons Rhizomes Bulbs suckers colonal fragmentation plantlets bulbils
16
Q
stolons
A
branches or stems that run just above the surface of the soil and generate ramets at nodes touching the ground.
17
Q
rhizomes
A
underground horizontal stems growing near the soil surface.
18
Q
bulbs
A
underground rosette stems that store nutrients and can divide to form new ramets.
19
Q
Suckers
A
meristematic buds on some of the near surface roots capable of generating new stems and leaves.
20
Q
clonal fragmentation
A
pieces of the plant break off and are capable of rooting to form new ramets which are not physiologically integrated with the other ramets.
21
Q
plantlets
A
small plants created vegetatively
Plantlets along leaves that can become dislodged and form new plants
22
Q
bulbils
A
tiny bulb-like organs on inflorescences or leaf axils.
23
Q
What is a genet?
A
a genetic individual. Product of a single seed. A single genet may consist of several functioning ramets. Example: a stand of quaking aspens may all be one genet, but each perceived individual tree is a ramet.
24
Q
What is a ramet?
A
potentially physiologically independent unit of a genet. Ramets can be dependent or independent.
25
relationship of ramets and genets
The distribution of ramets depends on competition among genets and distribution of resources.
26
What are adventitious roots?
roots that originate from the stem. Help tree-like monocots increase in girth.
27
What is the difference between “Guerilla” and “phalanx” growth.
Phalanx = ramets penetrate their competitor’s territory like a classic army (grouped tightly together).
Guerilla = ramets penetrate their competitor’s territory like a guerilla army (more dispersed).
This terminology has fallen out of favor since grouped / dispersed is subjective, plants have multiple competitors (and may employ multiple strategies), and the perceptions of grouped / dispersed are scale dependent.
28
What is clonal integration?
the degree to which the ramets within a genet are physiologically interconnected. Includes resource translocation and information communication.
29
What is agamospermy?
asexual seed production. Involves partial meiosis w/o reduction division so chromosome number remains unchanged or no meiosis.
30
Advantages of asexual reproduction
Preserves favorable genetic combos
Reproduction at low population densities
Eliminates need for flowers
Individuals pass on twice as much genetic material as their sexual relatives
Having interconnected ramets allows ramets to exist in nutrient poor locations because of resource sharing within the entire genet. This can improve overall vigor of the genet.
31
What is a pollination syndrome?
association of certain floral attributes with particular types of pollinators (usually taxonomic orders or classes). Results from tightly coevolved mutualisms.
Plants can also evolve to be pollination generalists that are visited by a variety of animals.
32
Bee pollinated
yellow, sweet smelling, broad enough for bees to contact stigma and anthers, produce nectar during day.
33
Bird-pollinated
red or orange, produce copious nectar (but little scent), have long tubes or spurs.
34
Moth pollinated
white or pale yellow
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bat pollinated
white or brown, musty odors
36
Flies gnats
animal dung or rotting tissue
37
What is a dispersal syndrome?
morphological characterstics of seeds corresponding to their dispersal agents. More detail?
38
What opportunities do plants have for movement?
Plants have the opportunity to move their gametes or their seeds.
39
What is a seed?
embryonic sporophyte embedded in a female gametophyte and covered in one or more integuments derived from the maternal sporophyte.
40
Diaspore
dispersal unit of a plant (fruit, seed, or related structure).
41
What is a fruit and what is its function in dispersal?
Fruit = matured ovary (or ovaries) of one or more flowers and associated structures.
Function = protect seed and aid in seed dispersal. These functions often conflict.
42
What is an eliasome and what is its function in dispersal?
a lipid body attached to a seed. This lipid body attracts ants which carry it to their nest to eat and discard the seed.
43
What is a dispersal kernel?
a model that estimates the probability of a seed dispersing at various distances form the parent. Difficult to obtain enough data for long distance dispersal.
Wind dispersed seeds migrate faster than animal dispersed seeds.
44
what is a seed bank
seeds buried in the soil. Single species or whole community.
45
seed bank dispersal through time
Seed banks allow plants to disperse through time. Short-lived plants tend to have long-lived seeds while long-lived plants tend to have short-lived seeds. Larger seeds are also more short-lived.
The abundance of species in the seed bank may have little relation to the abundance of species above ground. Some species are only present as seeds w/in the soil at a given time.
46
Alternation of generations
a haploid gametophyte producing haploid gametes alternates with a diploid sporophyte producing haploid spores.
Diploid generation is dominant in angiosperms and gymnosperms. Haploid generation is dominant in bryophytes.
Bryophytes must live in moist places and be low to the ground so they can be reached by swimming sperm. Bryophytes must also be near each other so sperm don’t have to swim too far. The gametophyte must be large enough to nourish the sporophyte initially.
In seed plants, gametophytes mature inside sporophytes and are nourished by them. Sporophytes don’t have to live in wet environments and be close together. The gametophyte is also much smaller.
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Gametophyte
haploid generation that produces gametes. Only the gametophyte technically has a gender.
48
Sporophyte
diploid generation that produces spores (haploid somatic cells).
Example: pine trees produce short-lived cones in which male gametophyte is produced and long-lived, woody cones in which female gametophyte is produced.
49
Sexual life-cycle in angiosperms: Sporophyte // gametophyte
The flower undergoes meiosis to produce haploid daughter spores. The spores divide mitotically to produce pollen grains (microgametophytes) or embryo sacs (megagametophytes).
Pollen grains are on the anther at the end of the stamen. Pollen grains undergo two more mitotic divisions to produce a vegetative cell that divides again to form two sperm cells.
Embryo sac develops inside an ovule which is in an ovary. The embryo sac consists of 7 cells one of which becomes an egg.
The pollen germinates after landing on the stigma.
The vegetative cell grows a tube which penetrates stigma and style and ultimately the ovary and the ovule inside the ovary.
Double fertilization = the sperm cells travel down this tube where one fertilizes the egg cell (becomes zygote, new sporophyte) and the other fertilizes a triploid cell (becomes endosperm, nutritive source).
Double fertilization does not occur in gymnosperms, so the nutritive tissue is haploid, and endosperm is absent. Development usually takes longer (sometimes years).
The ovule becomes a seed, and the ovary becomes fruit. Fruit tissue and some seed tissue come from maternal sporophyte. Only the embryo and endosperm are new genetic individuals.
Seeds allow independence of reproduction from water. The presence of different kinds of tissues has allowed evolution of mechanisms to limit mating.
50
Assortative mating
plants with similar phenotypes mate with each other more than they would by chance alone.
51
Disassortative mating
plants with different phenotypes mate with each other more than they would by chance alone.
52
What is a population?
An ecological population refers to a group of individuals within a single species that occupy the same space at a given time. Populations are divided from other populations of the same species by geography, predation, temporal distribution, or other factors. These groups may also be defined as the members of a species which are not inhibited from breeding together?
53
What is meta-population?
a group of populations of the same species which do not occupy the same region at the same time but may continue to affect each other.
54
What are the main components of population structure
Local population size and density (count and self explanatory)
Age structure – age fractionation through population
Size structure – size fractionation through population
Dispersion – spatial distribution of individuals (Uniform, Random, Clumped)
Stage structure -
55
What is population density and how is it measured?
Population density is a metric of # individuals / unit area
It may be calculated using quadrat sub-sampling (count per area)
Or by using point or line based plotless sampling
56
What is meant by population dispersion in the context of local populations?
This refers to the localized structure the population takes. This may be roughly uniform, random, or aggregated
57
-How can population dispersion be measured?
Population dispersion can be found using the poisson distribution. A table exists which confers the likelihood of finding x number of individuals within a plot given a mean density per plot. Using chi squared calculation you may compare the expected and true and determine whether there is a difference from the null expectation that individuals are randomly sorted. A greater number of high count boxes indicates an aggregated structure, and a greater number of low count boxes indicates uniform
58
What factors can influence the spatial distributions of individuals in a population?
Plants cannot move- This means that factors affecting the population's distribution must be either environmental characteristics or characteristics of their spread. This may include:
Resource or water hotspots
Local light availability
Topography
Seed spread strategy (Wind, water, animal spread)
59
Are assessments of spatial distribution scale-dependent? If not, why?
Determining spatial distribution can be affected by scale,
Plant sizes may drastically differ, and as such a single quadrat size will not be appropriate for all surveys.
Cell size may also be too narrow or too inclusive to determine local patterns.
60
What is meant by the age or size distribution of a local population? What can an age or size distribution potentially indicate about the past or future of a population?
To create this structure, age or size is measured and each individual is included into appropriate bins. These bins can be used to make inferences about when and where changes are occurring along the size/age distribution.
61
Describe the geometric population growth model
The geometric growth model is one which assumes that all individuals are contributing to reproduction and that they are contributing in a way that is equal across individuals and time. Unlike in the exponential growth model these growths occur at fixed intervals.
62
What are density dependent population processes?
A density dependent process is a process whose effect size is dependent on the population density of a given population that is being affected.
63
Demographic stochasticity vs. environmental stochasticity. How do they relate to population size?
Demographic stochasticity refers to the chance of an event that results in mortality occurring within a single individual's fate. These events at the population level result in decreases in the long-term growth rate and can only result in decreases and not increases. At the population level this is an example of a sampling error
Environmental stochasticity refers to the changes which can occur to the characteristics of the environment that the population is growing in. These may realize changes to fertility or fertility.
While environmental stochasticity has an equal effect on populations of any size, demographic stochasticity (variations in individual fates), has the greatest effect on populations of smaller size
64
What does mortality refer to?
Mortality refers to the number of individual deaths within the population. It is the counter to feundity.
65
What are the processes that add and subtract individuals from a population?
Births – New individuals germinating
Deaths – Individuals leaving the mortal coil
Imigration
Emigration
66
What is meant by the term Population Flux?
Population flux is the change that occurs in the population over time as a result of mortality and births.
67
What is meant by directional versus stochastic population flux?
Stochastic population flux is a change that occurs not due to a long term trend. These changes may be positive or negative but are occurring due to a stochastic (random) occurrence.
A directional flux is one that is occurring as a part of a longer trend, that is followed in a direction regularly from year to year. This process would create a directional vector on a representative graph.
68
What is meant by Geometric Rate of Increase (λ) and how is it calculated?
69
Be able to calculate λ from knowledge of population size at two points in time.
70
What are the differences between Type 1, Type II and Type III survivorship curves?
71
-Given a value of λ and initial populations size (N) be able to predict population size in the future. -What is population demography?
72
Be able to construct a survivorship curve from demographic data?
73
What is a life table? What are the components of a life table?
74
-What is Fecundity?
75
Be able to construct a life table from survivorship and fecundity data and calculate Net Reproductive rate (Ro).
76
What is a population projection Matrix? What is it used for?
77
What is a transition probability and how is it generally estimated in a demographic study?
78
What are the fundamental differences between stage-and age-based life cycle diagrams?
79
Given information about life history stages, transition probabilities and initial population size, be able to: a) assemble the appropriate projection matrix; b) project the population into the future: c) calculate (λ); and d) calculate the stage distribution for each iteration. -What is the stable stage distribution? What is its significance?
80
What is the stable growth rate (λs)? What is its significance?
81
Define and be able to interpret sensitivity and elasticity analyses?
82
Define Demographic and Environmental Stochasticity? Why is stochasticity such an issue for small populations?
83
What are the seven fundamental life history traits that we discussed in class?
1. Survivorship – age or stage specific probability of survival
2. Fecundity – number of offspring per reproductive episode
3. Maturity – age at first reproduction
2. Parity – number of episodes of reproduction
(Semelparity = reproduces once; Iteroparity = reproduces multiple times)
5. Lifespan
6.Body size/offspring size
7.Intrinsic capacity for growth (r; Intrinsic or maximum per capita rate
of increase; “little r”).
84
-What is fitness? What are the components of fitness?
Fitness=reproductivity output*probability of survival
85
What is the principle of allocation?
Individuals have a limited amount of energy and
resources to spend on growth, maintenance (survival) and reproduction.
Different environments “select for” different allocational strategies to
enhance fitness and maintain positive rates of population growth.
86
Life history trade-off
A trade-off exists when an increase in one life history trait (improving fitness) is coupled to a decrease in another life history trait (reducing fitness
87
What is r-K selection theory?
Posits that contrasting suites of life history adaptations will be favored in high versus low population density environments.
88
What are the general features and trade-offs of so-called “r-selected” and” K-selected” species?
R-selected= favored in unstable, low density habitats (disturbed
or ephemeral environments where N is typically much lower than K).
Natural selection favors adaptations that increase rm. Favors rapid
growth, early maturity, high fecundity.
K-selected= favored in stable, undisturbed environments where populations densities remain high. Natural selection favors adaptations that increase K and that enable individuals to survive when N≈K (in the face of low resource availability and intense resource competition). Favors efficiency of resource use (allocation to maintenance and survival instead of rapid growth and high fecundity).
89
What are the basic components and predictions of Grimes Triangular, C-S-R model?
The C-S-R Model posits that there are two key environmental axes driving plant life-strategy evolution: disturbance and environmental stress. Allocational trade-offs result in the evolution of three broad life strategies in response to different combinations of Disturbance and Stress
Disturbance: Physical damage to vegetation, that alters plant density and biomass (landslides, grazing, soil disturbance, fire, wave action, flooding, harvest/ mowing etc.).
Stress: Abiotic factors in the environment that limit plant growth, survival, and biomass. Stressors may include low nutrient and water supply, chemical inhibition (toxins, low pH etc.).
90
What are the general hypothesized characteristics of C, S and R species? In what types of habitats should you find these species?
Competitors (C-strategists): plants specialized for rapid resource
uptake and the allocation of these resources mainly to growth, making
them proficient in the competitive suppression of other species.
Competition: The attempt of neighboring
plants to use the same resources
```
C-strategists
Rapid growth rate
High productivity
High resource uptake rates
High resource requirement
Highly plastic growth
Often clonal
Often tall, casting shade
Intolerant of stress
```
```
Stress Tolerators (S-strategists): Resource-conservative species
S strategist
Slow growth rate
Low productivity
Low resource uptake rates
Low resource requirements
Long-lived
Poor competitors
```
Ruderals (R-strategists): Resource-conservative species (Weeds)
```
R strategist
Fast growth rate
Rapid life cycle
High reproductive rates
Large seed crops
Good dispersers
Poor competitors
```
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Summer annuals
- Seed are dormant over the winter
- Germinate in the spring
- Set seed in summer or fall
92
Winter Annuals
- Common in places with moist winters and dry summers
- Germinate in the fall,
- Over winters vegetatively as a rosette
- Flowers and sets seed in spring before the onset of summer drought (monocarpic)
93
Monocarpic (semelparous) Perennials
-Reproduces once and then dies, but can exist vegetatively from 1-many years before
reproducing
-Biennials are monocarpic perennials that flower and die in the second growing season
-Other monocarpic perennials live as long as it takes to accumulate the resources
necessary to set seed
94
Polycarpic (iteroparous) Perennials
- Typically live more than one growing season
| - reproduce more than once (polycarpic)
95
Herbaceous Polycrpic Perennials
-Shoots die back to ground level during winter (different than for woody plants)
-Meristems (growing points) are at the surface or below-ground
Advantages of the herbaceous habit (compared to woody habit):
-not vulnerable during the unfavorable season (winter or drought)
-does not have to allocate resources to structural support (wood)
Disadvantages:
-an individual’s position in the canopy must be re-established every year
-below-ground storage organ is vulnerable to herbivores and pathogens
96
Polycarpic Trees and shrubs
-High allocation to structural support (wood)
-Shoots maintain their position in the canopy during the unfavorable season
**a strategy for competing for light?
-Delayed investment in reproduction (compared to most Herbaceous Perennials)
to ensure survival
97
What is reproductive effort?
has two components: energy invested by the female and the way that energy is proportioned into individual offspring.
98
Smith and Fretwell (1974) model for predicting seed size
Smith and Fretwell (1974) developed a model predicting that when environmental conditions are predictable there should be a single optimal size for seeds.
99
Intraspecific
competition among individuals of the same species; Negative Intra-specific density-dependence, driven by resource competition; because individuals of the same species have identical/very similar resource requirements (share the same resource niche), we expect that intraspecific competition to be especially intense
100
Interspecific
competition between individuals of two or more species
101
Interference
competition that involves direct or aggressive interactions among individuals (e.g. allelopathy in plants, territory in animals
102
Exploitative
competition that involves indirect negative interactions that occur via the joint consumption of a shared resource in short supply
103
Apparent
indirect negative interaction mediated by a natural enemy (herbivory, predation, pathogen)
104
-What is the law of Constant Yield?
Plants in monoculture will grow to a constant yield regardless of initial density. Final Yield (biomass K) is determined by total resource level, not initial density
105
-With respect to plants growing in monoculture, what is meant by a size asymmetry? What causes it?
The initial size distribution of plants are the same but over time the size distribution between individuals is variable and disproportional. The reasons for this are small differences in local growth environment, micro-heterogeneity, slightly larger plants might get a larger share of resources, genetic variability in germination timing (e.g. early emerging plants can lead to higher seedling weight). You can control for everything but the slightest differences can lead to disproportional sizing in plants.
106
Be able to define and discuss the process of self-thinning?
In densely-planted populations, thinning mortality begins earlier and at smaller average individual plant sizes. The self-thinning line predicts the mean plant size at which a monoculture of a given initial density will start to thin and the trajectories exhibited once thinning starts
107
-What is the DeWitt Replacement series?
The de Wit replacement series is a widely used technique to assess the resource use and productivity in systems with competing species (especially plants). It is also very useful to evaluate the interspecific and intraspecific competition in different species.
See shrepoint for example
108
-What is the Competitive Exclusion Principle?
The competitive exclusion principle says that two species can't coexist if they occupy exactly the same niche (competing for identical resources). Two species whose niches overlap may evolve by natural selection to have more distinct niches, resulting in resource partitioning.
109
-What is R*
R* = Minimum concentration of resource needed for a population to
survive
R* = Resource concentration in monoculture where population birth =
death; biomass gain = biomass loss (N = K)
R* = Resource concentration when the rate of resource uptake
matches the rate of supply
R* can be viewed as an emergent trait that can differ
among competing species and reflecting differences in
their resource needs and their ecological traits related to
resource acquisition – providing a basis for prediction
