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Characteristics, Evolution and Life Cycle of Plants - Coggle Diagram
Characteristics, Evolution and Life Cycle of Plants
Characteristics:
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They are eukaryotes with cell walls containing cellulose and carry photosynthesis using chlorophyll a and b.
They need sunlight, gas exchange, water and minerals.
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Gas exchange: They need it too support cellular respiration and to develop photosynthesis. They exchange it with the atmosphere and the soil.
Water and minerals: They consume water when the sun is shining. Their structure limit water loss and speed. When they absorb water they absorb minerals. Minerals are nutrients in the soil. They are distributed in the plant body.
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Evolution:
First and plants:
The demands of life made the evolution of plants to be more resistant to the rays of the sun, more capable of conserving water and reproduce without water.
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They were a few centimeters tall, without leaves and roots.
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Origins:
They were unicellular, but others were composed of multiple cells.
Algae has cell walls, reproductive cycles and photosynthetic pigments identical to those plants.
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The studies of their genomes showed that they were closely related to other plants so it should be consider part of the plant kingdom.
Life Cycle:
It has two alternating phases, diploid phase(2N) and haploid phase(N). And what makes them different is the alternation of generations.
Multicellular haploid (N). They are gametophyte also called gamete producing plant. And they carry a single set of chromosomes in their cells.
Multicellular diploid (2N). They are sporophytes also called spore producing plant. And they have two sets of chromosomes.
The first thing that happens is that a sporophyte produces haploid spores though meiosis. Then the spores grow into multicellular structures called gametophytes. Then each one produces sperm and egg cells, called reproductive cells. Then during fertilization sperms and eggs fuse between them and produce a diploid zygote. Then the zygote develops into a new sporophyte and the cycle begins again.