Last week we saw how the first living things, cyanobacteria, appeared about 3.5 billion years ago. These are the precursors to a wide range of multicellular marine organisms, including algae, which altered the atmosphere through photosynthesis, and allowed the evolution of the plants And wild animals.
Mine: Algae, Earth’s first lungs
We do not know how to migrate Sea plants Earthed, however It is believed that some algae evolved and thrived after they stayed on the surface of the earth and conquered the air, that is, they developed properties that allowed them to live outside the water and protect themselves from the elements. The oldest fossils of non-aquatic plant life, dating back to the Silurian period (438 to 408 million years ago), are algae or algae.
Algae are plants that grow at ground level, on average no more than 5 cm high, because they lack a vascular system that carries water and minerals through the plant (stems, roots, or veins that distinguish leaves). Most algae species are only preserved in the fossil record, but some algae still thrive.
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Some algae developed primitive shapes of roots, leaves, and stems, but they were not significantly differentiated or developed. They were the most important innovations that allowed their grandchildren to thrive Embryogenesis (with spores and then seeds), and three innovations in its organic tissues: cuticle, stomata, and vascular bundles.
The epidermis protects the leaves from the sun, wind and heat; They prevented drought and other damage from the lack of water to protect them. Stomata are small airways that allow gas exchange – the entry of carbon dioxide and the exit of oxygen – in a controlled manner. The ability to open or close these air gates allowed for the plants Adapting to internal and external conditions, such as the availability of external gas or increased internal gas, or preventing dehydration, as is the case with aloe vera.
Vascular bundles refer to the tubular structures that allow water and material to flow, which is equivalent to our veins and arteries. The first is vascular structures Ground plants Allow for root development that allowed access to water and nutrient sources from the soil.
The emergence of the vascular system Allow for the development of ferns and horsetails (“Horse’s tail”, in Greek). these the plants, Whose first ancestral forms appeared in the Devonian period, between 408 and 360 million years ago, and are abundant today, especially in humid and warm regions such as our forests.
“The emergence of the vascular system gave way to the development of ferns and horsetails.”
Flat-leaved ferns were more successful than horsetail, with leaves like small rollers attached to a central stem. Most of the horsetails, which had stems or trunks up to 10 meters in height, are extinct in the Carboniferous zone. This period of 60 million years is called the carboniferous because of the abundance of vegetation, which later formed the main layers and deposits of coal that are mined today.
The Greek Aristotle (384-322 BC) was the first to distinguish between plants, in that he distinguished between living things that are both animate and inanimate. A more accurate classification was made only after the Swedish Carlos Linnaeus (1707-1778) established the scientific classification. Linnaeus established three kingdoms: plant, mineral and animal. Today we know that this distinction between the plant kingdom is more complex. It is no longer listed under the same definition the plant Many algae and fungi: It is understood that plants are multicellular organisms whose cells contain walls of cellulose, which produce these and other nutrients through the process of photosynthesis.
This does not mean that some the plants Parasitism phase (Where they extract a portion of their nutrients from another plant), fungal nutrition (where they coexist with the fungi that produce food for them) and even capture and digest insects.
Mine: Aloe Vera, Beautiful Succulents
The simplest reproduction is asexual, as there is no exchange of cells with genes from different ancestors. For example, In some the plants Parts of the main body are separated by cloning method. Vegetative reproduction initially developed in algae, after which spores were produced that also adapted to some of the first land plants.
Algae have developed a reproduction different from their aquatic ancestors: sexual reproduction. Here the cells carry the genetic material to exchange and integrate with that of the other samples. The evolutionary advantage of sexual reproduction is that it ensures that offspring inherits the genetic material from individuals who, due to genetic changes or mutations, have been able to adapt and survive under different conditions. Hence, the exact same form, which will be outdated and unable to thrive, is not reproduced.
This does not negate the success of asexual reproduction, which can also result in variations. For example, Some plants use their root system to store nutrients along with their reproductive nodules, each of which can lead to new emergence the plant. This is the case for tubers like potatoes, which contain hundreds of varieties and have a common ancestor.
Variety of flowers
Explaining flower development may take several pages. But over millions of years, its evolution in parallel with the emergence of insects and other animals led to the success of those that could attract transportation that carried pollen (genetic material) or seeds (the final product) to plants and other places. Transporting pollen and seeds up to hundreds of kilometers and in very diverse environments has given an enormous boost to species diversification.