1.6-1.8Free
Your guide: Miss AimanThinks the human body is the best-designed machine in the syllabus.
Is a virus alive? The book says it is not even an organism.
Then we count life in a forest and ask how new species form.
Three topics in one lesson.
Viruses are acellular. They are not placed in any domain or kingdom. They have a nucleic acid (DNA or RNA) inside a protein coat. They have no metabolism. They need a host cell.
The ICTV sets the rules for naming and grouping them. The basis is genetic material, replication, shape and host.
By host: animal viruses, plant viruses, bacteriophages (infect bacteria), archaea viruses.
By shape: helical, icosahedral, complex, enveloped, non-enveloped. By genetic material: DNA viruses and RNA viruses.
Prions are protein only. Viroids are circular RNA only. Both cause infectious diseases in certain plants.
Biodiversity is the variety of life in ecosystems. It covers species, genes and ecosystems.
An ecosystem is living things plus their physical environment. A niche is the role of a species in its ecosystem.
Three levels of assessment: species level, genetic level, ecosystem level.
Random sampling gives every part of the area an equal chance. Benefits: less bias, reliable estimates, easy comparison, representative samples, and support for conservation.
Distribution methods: quadrat sampling, transect sampling, aerial surveys. Abundance methods: point counts, mark-recapture, quadrat counts, capture-recapture models, remote sensing.
A species is a group that can interbreed and make fertile offspring in nature. Ernst Mayr stressed reproductive isolation.
Cryptic species look the same but are genetically different.
Speciation: new species arise from a common ancestor through genetic change and reproductive isolation.
Four modes: allopatric (a barrier splits the population; Darwin's finches), peripatric (a small edge population), parapatric (neighbouring populations on a gradient), sympatric (same area; polyploidy or niche differentiation).
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Is a virus alive? The book says it is not even an organism.
Then we count life in a forest and ask how new species form.
Three topics in one lesson.
Viruses are acellular. They are not placed in any domain or kingdom. They have a nucleic acid (DNA or RNA) inside a protein coat. They have no metabolism. They need a host cell.
The ICTV sets the rules for naming and grouping them. The basis is genetic material, replication, shape and host.
By host: animal viruses, plant viruses, bacteriophages (infect bacteria), archaea viruses.
By shape: helical, icosahedral, complex, enveloped, non-enveloped. By genetic material: DNA viruses and RNA viruses.
Prions are protein only. Viroids are circular RNA only. Both cause infectious diseases in certain plants.
Biodiversity is the variety of life in ecosystems. It covers species, genes and ecosystems.
An ecosystem is living things plus their physical environment. A niche is the role of a species in its ecosystem.
Three levels of assessment: species level, genetic level, ecosystem level.
Random sampling gives every part of the area an equal chance. Benefits: less bias, reliable estimates, easy comparison, representative samples, and support for conservation.
Distribution methods: quadrat sampling, transect sampling, aerial surveys. Abundance methods: point counts, mark-recapture, quadrat counts, capture-recapture models, remote sensing.
A species is a group that can interbreed and make fertile offspring in nature. Ernst Mayr stressed reproductive isolation.
Cryptic species look the same but are genetically different.
Speciation: new species arise from a common ancestor through genetic change and reproductive isolation.
Four modes: allopatric (a barrier splits the population; Darwin's finches), peripatric (a small edge population), parapatric (neighbouring populations on a gradient), sympatric (same area; polyploidy or niche differentiation).
Q1. Why is random sampling important in a biodiversity study?
Every part of the area gets an equal chance. This cuts bias, gives reliable estimates, allows comparison, and makes the sample represent the whole area.
✗ “Viruses are the fourth domain.”
✓ The book says viruses are acellular and not classified in any domain or kingdom.
1. Which organisation sets the rules for classifying viruses?
(a) International Committee on Taxonomy of Viruses.
2. Viruses that infect bacteria are called:
(a) Examples: T4 phage and lambda phage.
3. Which level of biodiversity is about variety of genetic information?
(a) It helps species adapt to change.
4. Darwin's finches are the book example of:
(a) Islands separate the populations.
5. A transect is used to study:
(a) A line or strip across the study area.
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