Mszaki - biologia zakres rozszerzony klasa 1 lo

Summary

The script discusses the evolution of plants, highlighting the appearance of the first plants around 420 million years ago. It explains the dominance of gametophytes in the life cycle of mosses, liverworts, and hornworts, which are resilient and can grow in various environments. The process of fertilization and the development of sporophytes from zygotes are described, along with the unique structures of these plants. The role of mosses in water retention and peat formation is also mentioned, emphasizing their importance in ecosystems.

Takeaways

• 🌿 **First Plants**: Around 420 million years ago, the first plants appeared on land, which were small, club mosses with branched stems.
• 🌱 **Generational Transformation**: Both generations of club mosses, gametophyte and sporophyte, were similar in size, hence the generational transformation in this group of plants is called isomorphic.
• 🌼 **Evolution and Dominance**: Club mosses were replaced by other plant groups, most of which are ferns and seed plants, which developed a dominance of the sporophyte in their life cycle.
• 🍃 **Independent Evolution**: Mosses, liverworts, and hornworts represent three independent lines of plant evolution, each taking their own developmental path.
• 🌳 **Gametophyte Development**: In mosses, the gametophyte generation is dominant in the life cycle, consisting of small, usually perennial plants without roots, allowing them to utilize only the upper layer of soil.
• 🌲 **Pioneer Species**: Mosses are pioneer species, often settling in places inaccessible to other plants, such as bare rocks, trees, or wood.
• 🌱 **Simplicity and Resilience**: The simplicity of moss construction makes them very resilient and capable of growing almost everywhere.
• 🌬️ **Water and Fertilization**: The fertilization process in mosses requires water, which helps the sperm reach the egg, leading to the formation of a zygote.
• 🌱 **Sporophyte Development**: From the zygote, a sporophyte develops, which eventually grows within the gametophyte, forming a foot-like structure called the seta and a capsule at the top.
• 🌿 **Life Cycle**: The mature sporophyte detaches the upper part of the seta, which turns into a capsule, protecting the young sporophyte as it grows.
• 🌳 **Environmental Adaptation**: Mosses, especially peat mosses, not only improve water conditions in an area but also participate in the creation of peat, which is still used as a growing medium in horticulture.

Q & A

How long ago did the first plants appear on Earth?

The first plants appeared on Earth around 420 million years ago.

What were the earliest plants called and what did they look like?

The earliest plants were called rhyniophytes. They were small, with dichotomously branched stems and likely both generations of rhyniophytes, gametophyte and sporophyte, were of similar size.

What is the term for the generational change in this group of plants?

The generational change in this group of plants is referred to as isomorphic.

Which plants replaced the rhyniophytes?

Rhyniophytes were replaced by other groups of plants, most of which are all ferns and seed plants.

What are the three independent lines of plant development that did not follow the same evolutionary path as ferns and seed plants?

The three independent lines of plant development are mosses, liverworts, and hornworts.

How are mosses adapted to their environment?

Mosses are adapted to their environment by being small, usually perennial plants that lack roots and can only utilize the uppermost layer of soil.

What is the function of the hydroids and leptoids in mosses?

Hydroids are specialized cells that conduct water, while leptoids are cells that form a protective organic layer. They help in the structural support and water conduction in mosses.

What is the difference between a unisexual and a bisexual gametophyte in mosses?

A unisexual gametophyte in mosses has both male and female reproductive organs, while a bisexual gametophyte has either only male or only female reproductive organs on different individuals.

How does the fertilization process in liverworts differ from other plants?

In liverworts, the fertilization process leading to the formation of a zygote occurs in the presence of water, such as from rainfall, where the archegonial neck swells and opens at the top, and raindrops splash into the archegonium, releasing sperm to unite with the egg.

What is the role of the sporophyte in the life cycle of mosses?

The sporophyte develops from the zygote through mitotic divisions and grows attached to the gametophyte by a structure called the foot. It produces spores within a capsule that are then dispersed to grow new gametophytes.

How do mosses contribute to the formation of peat?

Mosses contribute to the formation of peat by growing in wet, acidic conditions where the lower parts of the plant do not decompose easily, eventually forming peat.

What is the use of peat that is formed by mosses?

Peat formed by mosses is used as a growing medium in horticulture.