Plant Reproduction and Ecology Quiz

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Questions and Answers

What is a potential reason that some plants produce no nectar?

They rely solely on pollinators that consume pollen.

They evolved in areas with an abundance of nectar-producing plants.

They have adapted to be pollinated by wind or water. (correct)

They have higher reproductive success due to increased animal visitation.

What does selfing refer to in plant reproduction?

Mating between different species to create hybrids.

Mating that occurs when pollen from one flower pollinates another flower.

Mating via self-pollination to produce seeds for the plant itself. (correct)

A strategy to enhance genetic diversity through multiple pollinators.

What is the selfing syndrome associated with?

An enhancement of visual display traits for attracting pollinators.

A decrease in pollen size and variety to ensure successful reproduction.

An increase in floral traits such as fragrance and nectar production.

A suite of traits linked to the transition from outcrossing to self-pollination. (correct)

How many flowering plants are typically classified as selfing species?

20% Signup and view all the answers

What is indicated by the concept of phenotypic integration in plant traits?

Changes in one trait can indirectly influence the evolution of other traits. Signup and view all the answers

What is outcrossing in plant reproduction?

Transfer of pollen from the flower of one individual to another of a different individual. Signup and view all the answers

What characteristic evolution can occur due to the traits being phenotypically integrated?

Traits from the same module evolve together due to interconnected selection pressures. Signup and view all the answers

What percentage of human infants are born with observable anatomical variants?

2% - 5% Signup and view all the answers

What is the Greek translation of the term 'teratogen'?

Monster-former Signup and view all the answers

What are congenital anomalies also known as?

Congenital anomalies Signup and view all the answers

Which of the following best describes teratogens?

Environmental agents that cause congenital variants Signup and view all the answers

What aspect of congenital anomalies can be categorized as 'functional'?

Cognitive variants Signup and view all the answers

What limitation is associated with working on monocots in plant research?

Monocots cannot be transformed easily. Signup and view all the answers

How does single-cell RNA sequencing (scRNA-seq) differ from bulk RNA sequencing?

scRNA-seq captures gene expression from individual cells, while bulk RNA is a mixture. Signup and view all the answers

What is an advantage of using scRNA-seq over bulk RNA sequencing?

scRNA-seq allows for the identification of distinct cell populations. Signup and view all the answers

What is a drawback of single-cell RNA sequencing mentioned in the content?

It loses information about cellular arrangements in tissue. Signup and view all the answers

What role do barcodes play in single-cell libraries?

Barcodes help identify the specific cell each gene came from. Signup and view all the answers

In the study of banana nectary cells, what was identified as being associated with putative nectary cell clusters?

Genes related to sucrose metabolism. Signup and view all the answers

Which method can be used in conjunction with scRNA-seq to obtain spatial information about cells?

Spatial transcriptomics. Signup and view all the answers

What is one of the proposed functions for certain genes found in the nectary cell clusters of bananas?

Production of nectar. Signup and view all the answers

What clusters were identified exclusively in the top half of the gynoecium of banana flowers?

Nectary cell clusters. Signup and view all the answers

What does sympodial branching produce in terms of aerial view?

A flat aerial view Signup and view all the answers

Which of the following types of branching maintains dominance of one tip at a time?

Monopodial branching Signup and view all the answers

In which branching type do tips split but maintain one dominant tip by alternating tips?

Pseudomonopodial branching Signup and view all the answers

Which of the following branching types allows two tips to emerge at the same time?

Dichotomous branching Signup and view all the answers

Which branching type is characterized by tips splitting while one maintains dominance?

Sympodial Signup and view all the answers

What does pseudomonopodial branching indicate concerning tip dominance?

One tip maintains dominance at all times Signup and view all the answers

How does dichotomous branching differ from monopodial branching?

It maintains dominance of two tips rather than one Signup and view all the answers

What defines the aerial view produced by alternate branching?

Flat aerial view Signup and view all the answers

Which type of branching allows for tips to split in different planes maintaining a single dominance?

Monopodial Signup and view all the answers

What is a characteristic feature of true branches in certain plants?

They keep producing new branches, flowers, or fruits. Signup and view all the answers

What is the significance of the study of branching patterns in Sargassaceae?

It builds stronger phylogenies for understanding brown algae. Signup and view all the answers

Which of the following statements regarding the genomes of brown algae species is correct?

Only a small number of brown algae genomes are known. Signup and view all the answers

How can transcriptomics be utilized in studying Sargassum?

It can use existing Sargassum data without needing genome sequencing. Signup and view all the answers

What distinguishes indeterminate true branches from determinate branches?

Indeterminate branches can keep producing indefinitely. Signup and view all the answers

Which genus among the following is part of the Sargassaceae family?

Sargassum Signup and view all the answers

What is the developmental execution of radial branching primarily concerned with?

The structural arrangement of branches. Signup and view all the answers

What type of data can provide new insights into the understanding of brown algae?

Transcriptomic data and analyses. Signup and view all the answers

What role does the study of Sargassum species play in a broader scientific context?

It helps in understanding marine ecosystem dynamics. Signup and view all the answers

Which statement accurately describes true branches in specific algae?

They may not lose their indeterminate status after events. Signup and view all the answers

Study Notes

Nectar and Nectarines: Evolution

Nectar is a nexus of plant-animal interactions, providing a habitat for microbial interactions.
Nectar contains nesocodin, a compound that makes nectar appear red.
Nectar attracts specific pollinators.
Nectar-producing organs exhibit diverse structures and mechanisms across angiosperms.

Nectar Evolution

Nectar and nectary diversity can be examined through an evolutionary developmental framework.
Nectary development involves factors that coordinate structure and function.
Gain or loss of nectaries influences nectary core components and characteristics.
Mechanisms behind nectar differences between species include:
- Some plants do not produce nectar because they are pollinated by wind or water.
- Primary pollinator rewards (e.g., oils, scents, pollen) may have shifted.
- The mating system may have shifted. (This appears to be related to self-pollination)

Shifts in Mating Systems

Outcrossing occurs between different individuals.
Selfing occurs via self-pollination.
Approximately 20% of flowering plants are self-pollinating.
Self-pollination relates to reductions in floral traits like flower size, pollen, scent, nectar, floral pigmentation, etc.
These traits often evolve together, due to phenotypic intergration
Traits from different modules can also evolve independently

Dr. Liao's Research

Investigation focuses on understanding whether reduced nectar production evolves independently from other floral traits in selfing syndrome.
Methods include: Studying Ipomea cordatotriloba (CORD) versus Ipoema lacunosa (LAC) to identify modules using recombinant inbred lines(RILS).
RILS are created via
crossed CORD and LAC parents to create F1 hybrids
selfing F1 created F2 generation
the F2 is a shuffle population of different genotypes/phenotypes
Dr. Liao selfed each F2 line, which resulted in more homozygous F3
F3 is used to identify genomic regions related to phenotypes of interest via statistical methods

Measuring Phenotypic Traits

Methods employed to measure phenotypic traits include: nectar volume, sugar content, nectary size, seed traits (length, width, mass).
Statistical comparisons are done between traits to find significant differences.
Genetic data is used to understand variance using variance-covariance components.
ddRADseg is used to find genotype and phenotype data.
The results indicate three distinct clusters, with seeds, nectar, and flowers forming their own clusers
The analysis finds that correlations within clusters are higher than between clusters

Genetic Basis of Nectary Development

Nectaries are important for flowering plant development.
Transcription factors (Crab's Claw in core eudicots & Stylish in non-core eudicots) affect nectary development.
Monocots often have septal nectaries, embedded within the gynoecium, which are visually detected through plant sectioning.

Single-cell RNA Sequencing

ScRNA-seq is used to identify clusters of cells that are associated with nectaries in bananas.
Methods
Nectary cells are located at the top half of the gynoecium in bananas "Ice Cream" (Musa)
comparison between the top/bottom halves of gynoecium
ScRNA-seq clusters are used to identify
metabolic genes associated with nectary functions (sucrose synthase, sucrose-phosphate synthase, B-fructofuranosidase)
transcription factors which include copies of AG, AGL11/STK, YABBY2
Drawbacks of this technique
Spatial information of cell placement is not available in ScRNA-seq.
Spatial information, as well as cell types, have to be inferred.
To get complete information on cells, combining it with spatial transcriptomics will allow for better understanding of the issue.

Radial Branching in Brown Algae

Brown algae, stramenopiles, are marine organisms that vary in size.
They are independently evolved from all other multicellular eukaryotes.
Similar branching patterns exist between brown algae species and A. Thaliana.
Branching patterns significantly influence the 3D structure of an organism.
Radial branching occurs in Fucales and Sargassaceae.
Growth occurs at terminal or apical meristems in stems, this trait mirrors those in higher plants.
Sympodial and monopodial are different types of branching in brown algae.

Mapping Branching in Sargassaceae

Research suggests that 5000 brown algae species exist.
Transcriptomics (without needing a full genome) is used to examine the genomes of these species.
New data was combined with existing data to understand CA Stephanocystis and Sargassums.

Studying Branching Developments

Dichotomous (sympodial) branching is hypothesized to stem from a singular apical cell.
The apical cell periodically splits to create two dichotomous branches.
In terms of radial branching, apical cell division patterns influence the overall branching patterns and eventually organismal form.

Plasticity

Plasticity is the ability of a genotype to express different phenotypes depending on environmental conditions.
Examples include
Bicyclus Ananya butterfly eyespots vary based on the wet/dry seasons.
Mouse lines might have differences in size or whisker length given the same genome
This can be related to nutrient levels, genetic mutation, etc,

Why Plasticity Impacts Evolution

Plasticity can allow populations to survive in new or changing environments.
This "buying time" allows beneficial mutations to occur (plasticity can lead to evolution).
Plastic responses enable early expressions of adaptive phenotypes.
Plasticity is sometimes critical for phenotypic changes, which may eventually lead to genetic changes and mutations, enabling adaptation.
It can help ensure the survival of a species enabling its existence through challenging conditions within the niche.

Case Study of Tomato Hornworms

Temperature affects the pigmentation of tomato hornworm.
Lower temperatures result in black pigmentation.
Higher temperatures result in green pigmentation.
Heat shocking plastic hornworms can lead to either the retention of a monophenic black color, or a polyphenic green color.
Through breeding, they were able to increase and decrease plasticity over generations of the black and green polyhenic variations.
The results indicate that the green polyphenic line is more plastic and the black monophenic line has no plasticity.

Case Study: Side-Blotched Lizards

These lizards can change color to match their environment.
This plasticity enables them to adapt to different environments.
This results in genetic mutations that allow for adaptive responses, given that they were ancestrally plastic.

How Plasticity-Led Evolution Works

Environmental changes trigger phenotypic changes in organisms through phenotypic plasticity.
Selection favors variation leading to heritable changes (genetic accommodation/selection).
Resulting in adaptive refinement of favored phenotypes (e.g., larger size in blue tadpoles).
Resulting in novel polyphenisms.
Selection may cause the loss of plasticity, via genetic assimilation. A novel phenotype results regardless of environmental triggers.

Case Study: Spadefoot Toads

Spadefoot toads normally develop as omnivorous tadpoles, but they can develop into carnivorous tadpoles (if they eat larger prey).
Carniverous forms can eat larger animal prey leading to faster metamorphosis, which can result in larger adult sizes, and better reproduction
Carniverous forms are advantageous in drought conditions when ponds dry up quickly
This shows plasticity for a single species in environmental conditions.

Case Study: Fetal Alcohol Syndrome

Ethanol is a devastating human teratogen.
Human exposure to ethanol (during gestation) can affect the frequency of offspring defects in the short-term or long-term.
Fetal alcohol syndrome results from exposure to ethanol during pregnancy.
Severity and types of alcohol-induced variants depend on the alcohol dosage and the developmental stage at the time of prenatal exposure (Wilson's 2nd and 6th principle)
Most critical period of development is the first trimester, which is when most major defects arise.
The effect of ethanol on the developing organism is complex and includes its effects on neuron migration.
Animal models have shown that ethanol exposure can cause cell death in cranial neural crest cells, which are important for facial development.

Developmental Origins of Disease

Non-adaptive responses to injury or toxins can result in phenotypic malformations.
Adaptive responses to environmental variation can be advantageous for survival.
Immediate responses for offspring survival (acute plasticity) may have future costs but these can be an advantage in the short run.

Predictive Adaptive Response

Response to environmental cues acting early in the life cycle
Induced by early environmental factors, and used by environmental plasticity, to modify the phenotype where the advantage of the induced phenotype is primarily in a later phase of the life cycle
Results in permanent change of the physiology/anatomy, in response to environmental conditions.
This is in response to a range of developmental environments, and not just extreme ones.
Some examples are the response to metabolic syndrome (Type II diabetes), obesity, high blood pressure.

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Description

This quiz explores key concepts in plant reproduction and ecology, including nectar production, selfing, and outcrossing. Dive into the intricacies of plant traits and their evolutionary implications. Test your knowledge on how these factors contribute to plant biodiversity.