which derived character appeared first during the course of the plants evolution

Full Answer

What is the evolutionary history of plants?

Plants are thought to have evolved from a class of freshwater green algae called the charophytes.

Which modern organisms are most closely related to the earliest plants?

DNA, structural, and biochemical evidence has conclusively pinpointed a particular group of freshwater green algae known as the charophyceans as the modern organisms that are most closely related to the earliest plants, and have also revealed important steps in plant evolution.

What is the pattern of evolution in plant evolution?

The pattern in plant evolution has been a shift from homomorphy to heteromorphy. The algal ancestors of land plants were almost certainly haplobiontic, being haploid for all their life cycles, with a unicellular zygote providing the 2N stage.

What was the first plant to develop a tree-like habit?

The first plants to develop secondary growth and a woody habit, were apparently the ferns, and as early as the Middle Devonian one species, Wattieza, had already reached heights of 8 m and a tree-like habit. Other clades did not take long to develop a tree-like stature.

What is the concept of evolution in plants?

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.

What kind of data were first used to create phylogenetic trees?

Many different types of data can be used to construct phylogenetic trees, including morphological data, such as structural features, types of organs, and specific skeletal arrangements; and genetic data, such as mitochondrial DNA sequences, ribosomal RNA genes, and any genes of interest.

Which group of organisms does not form a clade?

The green subgroup is not a clade; it is a paraphyletic group, because it excludes the blue branch which has descended from the same common ancestor.

Which level of classification within a lineage has the largest number of shared derived characters?

generally within the lineage. The largest number of the offshore fields drives characters should be found amongst the two organisms that are the member of the same kingdoms class domain family. Okay, the correct answer is kingdom.

What is a derived character?

A derived character is a trait that arose in the most recent common ancestor of a particular lineage and was passed along to its descendants.

What is derived trait?

Derived traits are those that just appeared (by mutation) in the most recent ancestor -- the one that gave rise to a newly formed branch. Of course, what's primitive or derived is relative to what branch an organism is on.

What is a derived character state?

derived -- Describes a character state that is present in one or more subclades, but not all, of a clade under consideration. A derived character state is inferred to be a modified version of the primitive condition of that character, and to have arisen later in the evolution of the clade.

What kind of analysis focuses on the order in which derived characters appeared in organisms?

Section 18-2: Modern Evolutionary ClassificationABWhat kind of analysis focuses on the order in which derived characters appeared in organisms?cladistic analysis8 more rows

How do derived genetic characters help reveal evolutionary relationships?

Explanation. The derived character in organisms reveals the trait that was passed on from the common ancestor to its descendants. Scientists look for this trait in order to properly classify or group organisms into the right clade.

What sort of characters are useful in constructing phylogenetic trees?

A phylogenetic tree may be built using morphological (body shape), biochemical, behavioral, or molecular features of species or other groups. In building a tree, we organize species into nested groups based on shared derived traits (traits different from those of the group's ancestor).

Which is the correct sequence from the least to the most comprehensive of the taxonomic levels listed below?

The Correct Answer is (C) Kingdom – Phylum – Class – Order – Family – Genus – Species.

What is evolutionary classification?

Evolutionary classification is a synthesis of the phenetic and phylogenetic principles. The school therefore describes itself as synthetic, drawing on the advantages, and avoiding the shortcomings, of the two purer schools of cladism and numerical phenetics.

How are phylogenetic trees constructed?

Building a phylogenetic tree requires four distinct steps: (Step 1) identify and acquire a set of homologous DNA or protein sequences, (Step 2) align those sequences, (Step 3) estimate a tree from the aligned sequences, and (Step 4) present that tree in such a way as to clearly convey the relevant information to others ...

Which of the following features would be used to construct a phylogenetic tree?

A phylogenetic tree may be built using morphological (body shape), biochemical, behavioral, or molecular features of species or other groups. In building a tree, we organize species into nested groups based on shared derived traits (traits different from those of the group's ancestor).

What is used to determine phylogeny?

The fossil record is often used to determine the phylogeny of groups containing hard body parts; it is also used to date divergence times of species in phylogenies that have been constructed on the basis of molecular evidence.

What is phylogeny based on?

Phylogeny attempts to trace the evolutionary history of all life on the planet. It is based on the phylogenetic hypothesis that all living organisms share a common ancestry. The relationships among organisms are depicted in what is known as a phylogenetic tree.

What is the evolution of plants?

The evolution of plants has resulted in a wide range of complexity, from the earliest algal mats, through multicellular marine and freshwater green algae, terrestrial bryophytes, lycopods and ferns, to the complex gymnosperms and angiosperms (flowering plants) of today. While many of the earliest groups continue to thrive, ...

How did land plants evolve?

The closest living relatives of land plants are the charophytes, specifically Charales; assuming that the habit of the Charales has changed little since the divergence of lineages, this means that the land plants evolved from a branched, filamentous alga dwelling in shallow fresh water, perhaps at the edge of seasonally desiccating pools. However, some recent evidence suggests that land plants might have originated from unicellular terrestrial charophytes similar to extant Klebsormidiophyceae. The alga would have had a haplontic life cycle. It would only very briefly have had paired chromosomes (the diploid condition) when the egg and sperm first fused to form a zygote that would have immediately divided by meiosis to produce cells with half the number of unpaired chromosomes (the haploid condition). Co-operative interactions with fungi may have helped early plants adapt to the stresses of the terrestrial realm.

How do trees shape their leaves?

Various physical and physiological factors such as light intensity, humidity, temperature, wind speeds etc. have influenced evolution of leaf shape and size. High trees rarely have large leaves, because they are damaged by high winds. Similarly, trees that grow in temperate or taiga regions have pointed leaves presumably to prevent nucleation of ice onto the leaf surface and reduce water loss due to transpiration. Herbivory, by mammals and insects, has been a driving force in leaf evolution. An example is that plants of the New Zealand genus Aciphylla have spines on their laminas, which probably functioned to discourage the extinct Moas from feeding on them. Other members of Aciphylla, which did not co-exist with the moas, do not have these spines.

What is the driving force of water transport in plants?

Therefore, evaporation alone provides the driving force for water transport in plants.

Why are floral structures different in plants?

There is enormous variation in floral structure in plants, typically due to changes in the MADS-box genes and their expression pattern. For example, grasses possess unique floral structures. The carpels and stamens are surrounded by scale-like lodicules and two bracts, the lemma and the palea, but genetic evidence and morphology suggest that lodicules are homologous to eudicot petals. The palea and lemma may be homologous to sepals in other groups, or may be unique grass structures.

How many generations does angiosperm have?

Further information: Alternation of generations. Angiosperm life cycle. All multicellular plants have a life cycle comprising two generations or phases. The gametophyte phase has a single set of chromosomes (denoted 1n) and produces gametes (sperm and eggs).

What was the Devonian cladogram?

The Devonian marks the beginning of extensive land colonization by plants, which – through their effects on erosion and sedimentation – brought about significant climatic change. Cladogram of plant evolution. Plants were not the first photosynthesisers on land.

How has plant evolution been shaped?

Plant evolution has been shaped by key morphological and developmental novelties that have improved plant’s fitness as terrestrial organisms . Here we describe and discuss some of these traits in an evo-devo context, emphasizing those that have allowed seed plants, and especially flowering plants, to diversify and become dominant on Earth.

Where are evolutionarily related plants from?

For instance, evolutionarily related plants from New Zealand, Nepal, and the Cape of South Africa are used to combat diseases of the same therapeutic spaces ( Saslis-Lagoudakis et al., 2012 ), which powerfully shows the self-determining discovery of the botanical value.

What is the vascular system of plants?

During evolution, plants have acquired a vascular system, which has greatly contributed to the success of land plants. The vascular system allows plants to rapidly transport water and nutrients over long distances between roots, growing deeply in soil, and shoots, growing upward toward the sun. Importantly, it also provides mechanical support for the plant body. The vascular system consists of xylem, phloem, and the intervening procambium, which produces cambial, xylem, and phloem cells. During secondary growth, the cambium continues to give rise to xylem and phloem cells. The evolution of secondary growth has enabled the emergence of large trees and long-lived plants. Procambial and cambial cells are referred to as vascular stem cells based on their functions ( Hirakawa et al., 2008 ).

What are the two main groups of seed bearing plants?

Seed-bearing plants (spermatophytes) can be subdivided into two major groups: gymnosperms and angiosperms. The name-giving difference between these lies in the organization of the reproductive organs. Gymnosperms bear ovules on scales, which are usually in cone-like structures as, for example, in pine. Angiosperms instead have their reproductive organs arranged in flowers. Another important difference is that flowering plants feature a double fertilization step to produce the (typically) diploid embryo and the triploid extra-embryonic endosperm ( Lersten, 2004 ). Despite these differences in seed anatomy and function, the development and basic body organization of the embryo are very similar among most higher plants ( Cairney and Pullman, 2007; Johri et al., 1992 ). Accordingly, embryogenesis in both groups undergoes three common phases. Initially the fertilized egg cell (zygote) undergoes elongation and after a few cell division rounds develops an apico-basal and radial axis. During the next phase, further cell divisions occur and the primordia of the fundamental organs for post-embryonic growth are established. A final phase of desiccation prepares the mature embryo for dormancy and equips the seed with storage products that aid the seedling in the process of germination ( Bewley and Black, 1994 ).

What is the most important event in plant evolution?

The evolution of seeds and flowers was major events in land plant evolution and probably the most important factors responsible for the dominance of gymnosperms and angiosperms on land floras for the past 250 million years (Myr). Little is known regarding genetic mechanisms that guided the evolution of seeds in the Middle Devonian, but evolution of flowers has received considerable attention by developmental and evolutionary biologists.

How does evolutionary reasoning help in drug resistance?

The evolutionary reasoning can be utilized for inferring mechanisms in, for example, drug resistance in cancer and infections, which could exemplify how thinking about evolution influences the plant selection in drug lead discovery and how phylogeny knowledge may be used to evaluate predicted biosynthetic pathways.

How many phytochemicals are found in plants?

At least 20,654 phytochemicals from 16,102 plants are associated with 1592 human disease phenotypes. Only 8% of 36,932 phytochemicals are localized in certain parts of the taxonomy ( Jensen et al., 2014 ). For example, the genus Lens ( Fabaceae, Fabales), which includes lentils, and Citrus ( Rutaceae, Sapindales), which includes orange, contain 60 out of 562 compounds and 42 out of 214 compounds, respectively, that are not found anywhere else on the taxonomy. On the other hand, compounds such as β-sitosterol, palmitic acid, and catechin are spread all over the taxonomy. It is possible that the synthesis of small compounds in plants is mainly defined by short-term regulatory rather than long-term evolutionary adaptation to the environment.

Who wrote the Origin and Early Evolution of Plants on Land?

Kenrick. P., and P. R. Crane. "The Origin and Early Evolution of Plants on Land." Nature 389 (1997): 33 – 39.

Who wrote the Origin of Flowering Plants and Their Reproductive Biology?

Friedman, W. E., and S. K. Floyd. "The Origin of Flowering Plants and Their Reproductive Biology." Evolution 55 (2001): 217 – 231.

How did gymnosperms evolve?

The gymnosperms probably evolved from an extinct phylum of seedless vascular plants, the progymnosperms, that appeared about 380 million years ago. The fossils of these plants, some of which were large trees, appear to form a link between the trimerophytes (another extinct phylum of seedless vascular plants) and true gymnosperms. Progymnosperms reproduced by means of spores like the former, but their vascular tissues were very similar to those of living conifers. The oldest true gymnosperms, which produce seeds rather than spores, first appeared about 365 million years ago. The evolution of seeds, with their hard, resilient coats, was almost certainly a key factor in the success of the group. A second factor was the evolution of pollen grains to protect and transport the male gametes. As a consequence of this, gymnosperms, unlike seedless vascular plants, were no longer dependent on water for successful fertilization and could broadcast their male gametes on the wind.

How many species of angiosperms are there?

Angiosperms. The angiosperms, or flowering plants, are all members of the phylum Anthophyta. There are at least 250,000 species, making the group easily the most diverse of all plant phyla. They share a number of features that distinguish them from other plant groups.

Why are vascular plants called eutracheophytes?

Later-appearing fossils and modern vascular plants are known as eutracheophytes because they have more complex conducting cells. Modern vascular plants are thought to be derived from a single common ancestor. The comparative study of fossil and modern vascular plants has been valuable in understanding the evolutionary origin of vascular tissues, leaves, and seeds.

What are the three domains of plant evolution?

Modern classification systems, based largely on molecular evidence, divide living organisms into three domains: Bacteria (also called Eubacteria), Archaea, and Eukarya. Plants are classified as a kingdom (Plantae) within the Eukarya; organisms that possess a nucleus , mitochondria , an internal cytoskeleton , and, ...

Why is it important to understand the origin of plants?

Understanding the origin of plants is important because early plants were essential to the development of favorable terrestrial environments and provided a source of food for animals. In addition, the earliest plants were ancestral to all of the food, fiber, and medicinal plants upon which modern humans depend.

How did plants evolve?

Likely, those areas where plants evolved was subject to periods of flooding and periods of drying, and characteristics that enabled some species to better survive during the dry periods evolved slowly. Adaptation to the drier conditions eventually enabled early plants to colonize the land. To fully appreciate the huge advantages that terrestrial migration had for plant development, it is necessary to understand the differences between aquatic and terrestrial environments with respect to requirements for plant growth.

How long have plants been around?

Fossil plant remains that clearly show features of true plants date back to at least 475 million years ago (Fig. 4). The fossil record provides small windows into the past, and it aids scientists in approximating what life forms existed during a certain period in time. Because it can take millions of years for evolutionary changes to become established and because it is more rare than common for fossilization to occur, scientists estimate that the earliest plants began to evolve prior to the first evidence of plants in the fossil record. In fact, some molecular evidence indicates that land plants could have appeared as early as 600 million years ago.

What are the closest relatives of land plants?

Modern land plants share some features with the group of green algae called charophytes, and charophytes are the closest relatives of the plant kingdom. This phylogenetc tree (Fig. 1) depicts the evolutionary relationships between charophytes and plants.

Why are ancestral plants important?

It is important to remember that ancestral plants had many more shared features with charophytes than those of modern plants. They would have been transitional between the green algae and the plants in existence today. The environment they occupied was most likely subject to periods of drying, such that they slowly evolved features that allowed them to exist in a terrestrial rather than aquatic environment. This theme of adaptation to environmental conditions, via natural selection, is very important in the study of plant evolution.

Why are plants dependent on water?

The ancestors of early plants were dependent on water, not only to maintain their moisture content but also for structural support. The buoyancy of water supports upright growth of giant marine seaweeds (e.g., kelp, Fig. 6) Consider the seaweeds that are often found washed up on the beach.

Why is it important to remember the fundamental role that plants play within an ecosystem?

Plants and other autotrophs are the basis for supporting heterotrophic life. Prior to colonization of the land by plants , there was little basis for support of animal or fungal life.

What is the dominant component of terrestrial ecosystems?

Plants are a dominant component of terrestrial ecosystems and are the source of energy for the majority of other terrestrial organisms. Modern plants descended from an ancestral plant that lived in an aquatic environment. We will study the evolutionary history of the plant kingdom to better understand the selective forces ...