Evolutionary Trends in Plants:
– Plant cells are totipotent, enabling asexual reproduction.
– Polyploidy is common, facilitating rapid evolution.
– Seed plants can enter dormancy, reducing extinction risk.
– Plant families are less affected by extinction events.
– Surviving plant taxa are often rare generalists thriving in vacant niches.
Polyploidy in Plants:
– 30-80% of plant species are polyploid.
– Many lineages show ancient polyploidy.
– Angiosperm and fern speciation involve ploidy increase.
– Polyploids display heterosis and novel variations.
– Novel variations in polyploids result from gene dosage effects and chromosomal rearrangements.
Photosynthesis in Plants:
– Cyanobacteria were primary producers in the Proterozoic Eon.
– Chloroplasts share similarities with cyanobacteria.
– Chloroplasts have their DNA and code for essential proteins.
– Green algae and cyanobacteria were major producers.
– Cyanobacteria remain crucial in marine ecosystems.
Plant Transcriptional Regulation Evolution:
– Transcription factors and networks drive plant development and stress responses.
– Novel transcription factor families emerged during evolution.
– Regulatory networks are vital for development and reproduction.
– Plant transcriptional regulation is crucial for stress responses.
– Stress responses play a key role in plant evolution.
Flower Evolution in Plants:
– Flowers promote cross-fertilization, masking deleterious mutations.
– Cross-fertilization leads to hybrid vigor.
– Inbreeding post-cross-fertilization can cause depression.
– Flowers enhance genetic diversity and adaptation.
– Cross-fertilization benefits noted by Charles Darwin.
Genetic Mechanisms in Plant Polyploids:
– Genetic and epigenetic mechanisms influence gene expression.
– Genomic rearrangements and gene expression changes occur in polyploids.
– Novel gene expression mechanisms are observed in polyploids.
– Active maintenance of phylotranscriptomic hourglass patterns is seen in plant embryogenesis.
– Polyploidy in flowering plants leads to advantages and disadvantages.
Plant evolution is the subset of evolutionary phenomena that concern plants. Evolutionary phenomena are characteristics of populations that are described by averages, medians, distributions, and other statistical methods. This distinguishes plant evolution from plant development, a branch of developmental biology which concerns the changes that individuals go through in their lives. The study of plant evolution attempts to explain how the present diversity of plants arose over geologic time. It includes the study of genetic change and the consequent variation that often results in speciation, one of the most important types of radiation into taxonomic groups called clades. A description of radiation is called a phylogeny and is often represented by type of diagram called a phylogenetic tree.
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