The Chromophyta have the shortest fossil history among the major algal groups. Some scientists believe that the group is ancient, whereas others point out that there is a lack of data to support this view and suggest that the group evolved recently, as indicated by fossil and molecular data. The oldest chromophyte fossils, putative brown algae, are approximately 400 million years old. Coccolithophores, coccolith-bearing members of the Prymnesiophyceae, date from the Late Triassic (227 million to 201.3 million years ago), with one reported from approximately 280 million years ago. Coccolithophores were extremely abundant during the Mesozoic Era (252.2 million to 66 million years ago), contributing to deep deposits such as those that constitute the white cliffs of southeast England. Most species became extinct at the end of the Cretaceous Period (145 million to 66 million years ago), along with the dinosaurs, and indeed there are more extinct species of coccolithophores than there are living species. The Chrysophyceae, Bacillariophyceae, and Dictyochophyceae date from about 100 million years ago, and despite the mass extinctions 66 million years ago, many species still flourish. In Lompoc, California, U.S., their siliceous remains have formed deposits of diatomite almost 0.5 km (0.3 mile) in depth, while at Mývatn in Iceland the lake bottom bears significant amounts of diatomite in the form of diatomaceous ooze, many metres in depth.
The Xanthophyceae may be even more recent, with fossils dating from about 20 million years ago, while fossil records of the remaining groups of algae, notably the Euglenophyceae and the Cryptophyceae, which lack mineralized walls, are negligible.
Classification of algae
Diagnostic features
The classification of algae into taxonomic groups is based upon the same rules that are used for the classification of land plants, but the organization of groups of algae above the order level has changed substantially since 1960. Early morphological research using electron microscopes demonstrated differences in features, such as the flagellar apparatus, cell division process, and organelle structure and function, that have been important in the classification of algae. Similarities and differences among algal, fungal, and protozoan groups have led scientists to propose major taxonomic changes, and those changes are continuing. Molecular studies, especially comparative gene sequencing, have supported some of the changes that followed electron microscopic studies, but they have suggested additional changes as well. Furthermore, the apparent evolutionary scatter of some algae among protozoan and fungal groups implies that a natural classification of algae as a class is impracticable.
Kingdoms are the most encompassing of the taxonomic groups, and scientists are actively debating which organisms belong in which kingdoms. Some scientists have suggested as many as 30 or more kingdoms, while others have argued that all eukaryotes should be combined into one large kingdom. Using cladistic analysis (a method for determining evolutionary relationships), the green algae should be grouped with the land plants, the chromophyte algae should be grouped with the aquatic fungi and certain protozoa, and the Euglenophyceae are most closely related to the trypanosome flagellates, including the protozoa that cause sleeping sickness. However, it is unclear where the red algae or cryptomonads belong, and the overall conclusion is that the algae are not all closely related, and they do not form a single evolutionary lineage devoid of other organisms.
Division-level classification, as with kingdom-level classification, is tenuous for algae. For example, some phycologists place the classes Bacillariophyceae, Phaeophyceae, and Xanthophyceae in the division Chromophyta, whereas others place each class in separate divisions: Bacillariophyta, Phaeophyta, and Xanthophyta. Yet, almost all phycologists agree on the definition of the respective classes Bacillariophyceae, Phaeophyceae, and Xanthophyceae. In another example, the number of classes of green algae (Chlorophyta), and the algae placed in those classes, has varied greatly since 1960. The five classes of green algae given below are accepted by a large number of phycologists, but at least an equal number of phycologists would suggest one of many alternative classification schemes. The classes are distinguished by the structure of flagellate cells (e.g., scales, angle of flagellar insertion, microtubular roots, and striated roots), the nuclear division process (mitosis), the cytoplasmic division process (cytokinesis), and the cell covering. Many scientists combine the Micromonadophyceae with the Pleurastrophyceae, naming the combined group the Prasinophyceae.
Because classes are better defined and more accepted than divisions, taxonomic discussions of algae are usually constrained at the class level. The divisions provided below, though commonly used, are by no means accepted by all phycologists.
“Phylum” and “division” represent the same level of organization; the former is the zoological term, the latter is the botanical term. The classification of protists continues to be debated, and a standard outline of the kingdom Protista has not been established. The differences between the classification presented below and the classification presented in the article on protists (see protist: Classification) reflect the taxonomic variations that arise from individual interpretations.
paraphrase the above information in seven sentences
The Chromophyta, a major group of algae, have the shortest fossil history compared to other algal groups. There is disagreement among scientists regarding the age of the group, with some suggesting it is ancient and others pointing out a lack of data to support this view. The oldest chromophyte fossil, thought to be a brown algae, is around 400 million years old. Coccolithophores, which are coccolith-bearing members of the Prymnesiophyceae, date back to the Late Triassic period around 227 to 201.3 million years ago. They were abundant during the Mesozoic Era and many became extinct along with the dinosaurs at the end of the Cretaceous Period. The Chrysophyceae, Bacillariophyceae, and Dictyochophyceae date back to around 100 million years ago and many species within these groups still exist today. The Xanthophyceae have fossils dating back around 20 million years ago, while the fossil records for other algae groups such as the Euglenophyceae and Cryptophyceae are minimal. Overall, the classification of algae into taxonomic groups has changed over time based on morphological and molecular studies, and the algae do not form a single evolutionary lineage separate from other organisms.
multicellular marine and freshwater green algae, terrestrial bryophytes, lycopods and ferns, to the complex gymnosperms and angiosperms (flowering plants) of today plants have undergone evolution. what are the differences and similarities from the ancient compares to the present algae
The ancient algae, including the multicellular marine and freshwater green algae, had simpler structures compared to the present algae. They lacked the complex vascular systems found in modern plants and did not have true roots, stems, or leaves. Their reproduction was primarily through spores and they had less specialized reproductive structures.
In contrast, present-day algae have evolved to have more complex structures. They have developed specialized tissues for transport of water, nutrients, and sugars. They also possess more advanced reproductive structures, such as flowers and cones, allowing for more efficient pollination and seed production. Many species have adapted to live on land, evolving adaptations to withstand dry conditions and to extract nutrients from the soil.
Despite these differences, there are also some similarities between ancient and present algae. Both ancient and present algae are photosynthetic organisms, utilizing chlorophyll and other pigments to convert sunlight into energy. They both play important roles in aquatic ecosystems, producing oxygen and serving as a food source for other organisms. Additionally, both ancient and present algae contribute to the global carbon cycle, absorbing carbon dioxide from the atmosphere and incorporating it into organic matter.
Overall, the evolution of algae from ancient to present-day forms has resulted in a diversification of their structures and life strategies, enabling them to thrive in various environments and fulfill crucial ecological functions.
how can i settle my mind from the trouble and score A grade in a test and examination and practical assignment write ups
Here are some tips to help you settle your mind and improve your performance in tests, examinations, and practical assignments:
1. Create a study schedule: Plan your study time in advance and allocate specific time slots for each subject or topic. This will help you stay organized and ensure you cover all the necessary material leading up to the test or examination.
2. Break it down: Break down your study material into smaller, manageable chunks. This will prevent overwhelm and make it easier to focus and retain information.
3. Practice, practice, practice: Engage in regular practice tests or quizzes to familiarize yourself with the exam format and questions. This will help build your confidence and improve your performance.
4. Seek clarification: If you have any doubts or confusion about certain topics or assignments, don't hesitate to seek clarification from your teachers or classmates. It's essential to have a clear understanding of the material to perform well.
5. Get enough sleep: Prioritize getting sufficient sleep before the test or examination. A well-rested mind will function better and improve your ability to concentrate and recall information.
6. Stay organized: Keep your study area neat and organized, free from distractions. Having a clear space will help you maintain focus and be more productive.
7. Breaks and self-care: Take regular breaks during your study sessions to relax and recharge. Engage in activities that help you relax and reduce stress, such as exercise, meditation, or hobbies. Taking care of your physical and mental well-being is crucial for optimal performance.
8. Positive mindset: Cultivate a positive mindset by reminding yourself of your capabilities and strengths. Replace negative thoughts with affirmations and visualize yourself succeeding in your test or assignment. Positive thinking can greatly impact your confidence and performance.
Remember, achieving top grades requires consistent effort, dedication, and effective study strategies. By implementing these tips and staying committed to your studies, you can increase your chances of achieving an A grade in your tests and assignments.
if i regularly listen to music and wat to study, how it will affect my studies?
The effect of listening to music while studying can vary among individuals. Some people find that certain types of music can enhance their focus and concentration, while others may find it distracting. Here are a few factors to consider:
1. Type of music: Instrumental or ambient music without lyrics, such as classical or instrumental soundtracks, is generally considered less distracting. It can provide a soothing and background atmosphere that may enhance concentration. On the other hand, music with lyrics or catchy rhythms can grab your attention and interfere with your ability to focus on studying.
2. Personal preference: Everyone has different preferences when it comes to studying with music. Some people require complete silence, while others find music to be helpful in creating a conducive study environment. It's important to understand your own preferences and experiment with different types of music to see what works best for you.
3. Task complexity: The impact of music on studying may also depend on the nature of the task. If you're engaging in more demanding, cognitively challenging tasks that require deep concentration and critical thinking, it may be best to avoid music that could divert your attention.
4. Background noise: In some cases, listening to music can help drown out distracting background noises. If you're studying in a noisy environment, carefully selected background music could serve as a buffer against external distractions.
It's important to note that while music can have positive effects on mood and motivation, it may not always be beneficial for complex study tasks or subjects that require undivided attention. It's recommended to assess your own productivity and concentration levels when studying with music and make adjustments based on what enhances your focus and comprehension.
In conclusion, the impact of listening to music while studying can vary from person to person and depends on factors such as the type of music, personal preferences, and the nature of the study task. It's essential to find a balance that helps you stay focused and productive without hindering your ability to comprehend and retain information.
write me a excellent and outstanding lyrics on the information provided below.
i always faithful to my girl frien for the two years by giving my best to her but she broken my heart and find a boy to marry him. i don't know the true reason why she left me but i suspect that her people from mother side influence her to find someone better than me.
(Verse 1)
For two long years, I was faithful and true,
Giving my all, my love just for you,
But now my heart's shattered, broken in two,
Left wondering why, wondering what I should do.
(Pre-Chorus)
You found another, a love to call your own,
Leaving me behind, feeling so alone,
Questions haunt my mind, like a thunderstorm's groan,
Did they influence you, every word they have sown?
(Chorus)
I trusted in our love, believed it was strong,
But now I'm left here, singing a different song,
My heartache is real, I've been led astray,
But I'll rise above it all, find a brighter day.
(Verse 2)
The whispers of doubt, the secrets they've shared,
Did they convince you that I couldn't compare?
But I stood by your side, through thick and through thin,
Now I'm left here, picking up the pieces again.
(Bridge)
I'll find my strength, rise above the pain,
Even though it feels like pouring rain,
I'll heal my heart, mend what's been torn,
For I deserve a love that's true and reborn.
(Chorus)
I trusted in our love, believed it was strong,
But now I'm left here, singing a different song,
My heartache is real, I've been led astray,
But I'll rise above it all, find a brighter day.
(Outro)
So farewell, my love, as I bid you goodbye,
I'll find my own path, spread my wings and fly,
You may have moved on, found someone new,
But I'll find my happiness, and it won't be with you.
give me the tone of the song lyrics provided below in sad voice and sounds
(Verse 1)
For two long years, I was faithful and true,
Giving my all, my love just for you,
But now my heart's shattered, broken in two,
Left wondering why, wondering what I should do.
(Pre-Chorus)
You found another, a love to call your own,
Leaving me behind, feeling so alone,
Questions haunt my mind, like a thunderstorm's groan,
Did they influence you, every word they have sown?
(Chorus)
I trusted in our love, believed it was strong,
But now I'm left here, singing a different song,
My heartache is real, I've been led astray,
But I'll rise above it all, find a brighter day.
(Verse 2)
The whispers of doubt, the secrets they've shared,
Did they convince you that I couldn't compare?
But I stood by your side, through thick and through thin,
Now I'm left here, picking up the pieces again.
(Bridge)
I'll find my strength, rise above the pain,
Even though it feels like pouring rain,
I'll heal my heart, mend what's been torn,
For I deserve a love that's true and reborn.
(Chorus)
I trusted in our love, believed it was strong,
But now I'm left here, singing a different song,
My heartache is real, I've been led astray,
But I'll rise above it all, find a brighter day.
(Outro)
So farewell, my love, as I bid you goodbye,
I'll find my own path, spread my wings and fly,
You may have moved on, found someone new,
But I'll find my happiness, and it won't be with you