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HELP..Biology Prelim - Life on Earth (1 Viewer)
- Thread starter Jensta
- Start date
Life on earth
It is believed that early earth had only some water vapour, hydrogen, hydrogen cyanide, lots of carbon dioxide, nitrogen and possibly ammonia and methane in the atmosphere. There was lots of electricity being discharged from overhead electrical storms, and no oxygen.
Theory 1: chemicals came from outer space
It is believed that early Earth was often being hit with meteorites. When some meteorites were tested, they were found to contain organic molecules (amino acids). This was evidence to organic molecules in outer space, which may have contributed to life on Earth.
Theory 2: the chemicals were already here
Haldane and Oparin hypothesised that all the chemical components necessary for life was already available on Earth. Later, Urey and Miller constructed an experiment whereby electrical impulses were discharged in a closed system with hydrogen, ammonia, methane and water vapour continuously. Results a week later showed amino acids had formed. The experiment proved that complex organic molecules could have formed from simple ones already available on Earth.
Fossils form if
• The organism is quickly buried
• The organism lies undisturbed
• The organism is prevented from decay
Evolution is the process of gradual change in a population of organisms over long periods of time that result in new species
Evolution of living things
1. Formation of organic molecules (amino acids)
2. Formation of membranes (developed to protect system of large complex organic molecules)
3. Procaryotic cells (first simplest cells)
4. Eucaryotic cells
5. Colonial cells (aggregation of similar cells to form a colony)
6. Multicellular organisms (have differentiated cells with specialised function)
Palaeontologic evidence of early life is fossil evidence. The oldest found fossils are those of the stromatolites and cyanobacteria, which have been dated to be 3400 to 3500 million years old.
Geological evidence of early life is oxidised rock. When autotrophic organisms evolved, oxygen was produced as a by-product and the change in atmosphere can be seen in the ancient banded iron and reed bedrock formations.
When the environment changed from and anoxic to an oxic atmosphere, the ozone layer formed which shielded much of the UV radiation from Earth. Anaerobic organism numbers declined, whilst aerobic organism numbers increased. With oxygen available for respiration, greater metabolic activity became possible and organisms could be more active. Organisms could increase their size and complexity and the better atmosphere allowed them to colonise the land.
With the invention of the microscope (namely, the electron microscope), it has been made possible to distinguish procaryotic cells from eucaryotic cells. Previously, it was not known that procaryotes did not have membrane bound nuclei and lacked organelles. Procaryotes play an essential role in the recycling of matter
Nitrogen-fixing bacteria are often found living symbiotically with plant roots (in nodules). They take free nitrogen from the air and convert it to nitrites and nitrates, which are used by plants. This allows plants to grow in nutrient poor soil and is an important part in the nitrogen cycle; is a type of cyanobacteria.
Classification helps:
• Scientists communicate with each other easily about organisms
• Scientists understand relationships between organisms
Kingdom (plants, animals, monera, protists, fungi), Phylum, Class, Order, Family, Species, Genus
From Kingdom down to genus, the organisms become more similar
Technology has forced scientists to re-classify and revise the classification system. Embryonic development research involves using microscopes to compare embryos.
Analysis of proteins and DNA can show relationships if two organisms have similarly proteins or bases. Mitochondrial DNA can also be used to infer at which time two related organisms had a common ancestor.
Organisms have two word names. The first is the genus, and is usually a Latin word, written with a capital first letter. The second word is the species and is always written with all small letters. Both are always written in italics.
Fossil evidence for extinct organisms may be incomplete or not show enough information for classification. The fossil may also be so old, that there are no obvious relatives alive for comparison
Comparison helps us understand the past, help with communication and help work out relationships.
that's what i have written on LOE, but it seems short, so maybe it's the main stuff...or just not enough...i don't know
It is believed that early earth had only some water vapour, hydrogen, hydrogen cyanide, lots of carbon dioxide, nitrogen and possibly ammonia and methane in the atmosphere. There was lots of electricity being discharged from overhead electrical storms, and no oxygen.
Theory 1: chemicals came from outer space
It is believed that early Earth was often being hit with meteorites. When some meteorites were tested, they were found to contain organic molecules (amino acids). This was evidence to organic molecules in outer space, which may have contributed to life on Earth.
Theory 2: the chemicals were already here
Haldane and Oparin hypothesised that all the chemical components necessary for life was already available on Earth. Later, Urey and Miller constructed an experiment whereby electrical impulses were discharged in a closed system with hydrogen, ammonia, methane and water vapour continuously. Results a week later showed amino acids had formed. The experiment proved that complex organic molecules could have formed from simple ones already available on Earth.
Fossils form if
• The organism is quickly buried
• The organism lies undisturbed
• The organism is prevented from decay
Evolution is the process of gradual change in a population of organisms over long periods of time that result in new species
Evolution of living things
1. Formation of organic molecules (amino acids)
2. Formation of membranes (developed to protect system of large complex organic molecules)
3. Procaryotic cells (first simplest cells)
4. Eucaryotic cells
5. Colonial cells (aggregation of similar cells to form a colony)
6. Multicellular organisms (have differentiated cells with specialised function)
Palaeontologic evidence of early life is fossil evidence. The oldest found fossils are those of the stromatolites and cyanobacteria, which have been dated to be 3400 to 3500 million years old.
Geological evidence of early life is oxidised rock. When autotrophic organisms evolved, oxygen was produced as a by-product and the change in atmosphere can be seen in the ancient banded iron and reed bedrock formations.
When the environment changed from and anoxic to an oxic atmosphere, the ozone layer formed which shielded much of the UV radiation from Earth. Anaerobic organism numbers declined, whilst aerobic organism numbers increased. With oxygen available for respiration, greater metabolic activity became possible and organisms could be more active. Organisms could increase their size and complexity and the better atmosphere allowed them to colonise the land.
With the invention of the microscope (namely, the electron microscope), it has been made possible to distinguish procaryotic cells from eucaryotic cells. Previously, it was not known that procaryotes did not have membrane bound nuclei and lacked organelles. Procaryotes play an essential role in the recycling of matter
Nitrogen-fixing bacteria are often found living symbiotically with plant roots (in nodules). They take free nitrogen from the air and convert it to nitrites and nitrates, which are used by plants. This allows plants to grow in nutrient poor soil and is an important part in the nitrogen cycle; is a type of cyanobacteria.
Classification helps:
• Scientists communicate with each other easily about organisms
• Scientists understand relationships between organisms
Kingdom (plants, animals, monera, protists, fungi), Phylum, Class, Order, Family, Species, Genus
From Kingdom down to genus, the organisms become more similar
Technology has forced scientists to re-classify and revise the classification system. Embryonic development research involves using microscopes to compare embryos.
Analysis of proteins and DNA can show relationships if two organisms have similarly proteins or bases. Mitochondrial DNA can also be used to infer at which time two related organisms had a common ancestor.
Organisms have two word names. The first is the genus, and is usually a Latin word, written with a capital first letter. The second word is the species and is always written with all small letters. Both are always written in italics.
Fossil evidence for extinct organisms may be incomplete or not show enough information for classification. The fossil may also be so old, that there are no obvious relatives alive for comparison
Comparison helps us understand the past, help with communication and help work out relationships.
that's what i have written on LOE, but it seems short, so maybe it's the main stuff...or just not enough...i don't know
I dont mean to be rude but your teacher thinks you are capable of doing it on your own? Notes are great help but that was your pre-assignment! Time management please! Stop playing games or watching too much tvJensta said:Thanks GREAT guys.. thanks so much for that.. melanie what you wrote was pretty straight forward so thats good lol.. thanks alot!!