Flashcards in Life on earth Deck (73)
What is Classification?
Similarities and differences between living things on Earth are used to put them into groups. This process is called classification. the first big division of living things in the classification system is called the five kingdoms
what is Species?
A species is a group of organisms that can breed together to produce fertile offspring.
A horse and donkey are different species - how do we know that?
The most common example to show this is with horses and donkeys. A horse and donkey can breed together: the offspring is called a mule. The mule is infertile, which shows that the horse and donkey are a different species.
what is Adaptation?
Adaptations are features that help an organism survive in the environment it lives in.
What do adaptations increase?
adaptations increase the organism’s chance of surviving. If the chances of survival are increased it also increases the chances that the organism will successfully reproduce.
What is a food web ?
A food web is simply a number of food chains joined together. It shows how the loss of one organism has an effect of other organisms in the food web. This is called the interdependence of living things
Give 4 common factors that can cause a species to become extinct?
Here are some factors that can cause a species to become extinct:
rapid changes to the environment, such as the climate
why are we very successful predators?
We compete with other living things for space, food and water, and are very successful predators
How do we know that many species have become extinct?
what is a quagga?
The quagga has a horse/zebra like face and stripes similar to a zebra.The last quagga alive in the wild was shot in the late 1870s. Some animals - such as the quagga - are extinct because of the direct activity of humans.
What is The dodo?
The dodo was a large flightless bird that lived on Mauritius, one of a group of islands in the Indian Ocean. The Dodo is extinct because of the indirect activity of humans.
why did the dodo become extinct?
The Mauritius islands were uninhabited, and the dodo had no natural predators. Then Mauritius were colonised by the Dutch in 1638. Dodos were hunted for food and easy to catch, because they were not afraid of people.
which new competitors did the Dutch bring to the Mauritus in the 17th century?
The Dutch also brought new competitors to the islands, such as pigs, cats and rats, which ate the dodos' eggs and young and were finally responsible for the extinction of the dodo.
What do plants do with energy from the sun?
Plants harness light energy to drive food production. By the process of photosynthesis,
Nearly all organisms are dependent on energy from the what ?
The Sun - Nearly all organisms are dependent on energy from the Sun
Describe the process of photosynthesis,
organic compounds like glucose are made from carbon dioxide and water using this energy. Plants only absorb a small percentage of the Sun’s energy for the process of photosynthesis. The energy is absorbed in chemicals that make up the plants’ cells
Can Animals make their own food? .
No - so they have to eat.r
Do all cells contain carbon?
Yes All cells - whether animal, plant or bacteria - contain carbon, because they all contain proteins, fats and carbohydrates. Plant cell walls, for example, are made of cellulose - a carbohydrate.
what is the carbon cycle?
Carbon is passed from the atmosphere, as carbon dioxide, to living things, passed from one organism to the next in complex molecules, and returned to the atmosphere as carbon dioxide again. This is known as the carbon cycle.
What was the first extinct species to have its DNA studied.
A Quagga - The quagga was the first extinct species to have its DNA studied. The results showed that the quagga was not a separate species as had been previously thought, but was a type of zebra.
what are the 3 parts of the carbon cycle?
1. Carbon is passed from the atmosphere, as carbon dioxide, to living things,
2. passed from one organism to the next in complex molecules, and
3. returned to the atmosphere as carbon dioxide again. This is known as the carbon cycle.
Removing carbon dioxide from the atmosphere
Green plants remove carbon dioxide from the atmosphere by photosynthesis. The carbon becomes part of complex molecules such as proteins, fats and carbohydrates in the plant
.Returning carbon dioxide to the atmosphere - this is the 3rd stage of the carbon cycle - how does it happen?
Organisms return carbon dioxide to the atmosphere by respiration. is not just animals that respire. Plants and microorganisms do, too.
The second stage of the carbon cycle is Passing carbon from one organism to the next - how does it happen?
When an animal eats a plant, carbon from the plant becomes part of the fats and proteins in the animal. Microorganisms and some animals feed on waste material from animals, and the remains of dead animals and plants. The carbon then becomes part of these microorganisms and detritus feeders.
what is Nitrogen fixation ?
Making nitrogen compounds from nitrogen in the air is called nitrogen fixation.
Nitrogen fixation happens in three ways - what are they?
1. The energy in lightning splits nitrogen molecules into individual nitrogen atoms. These react with oxygen to form nitrogen oxides. Nitrogen oxides are washed to the ground by rain, where they form nitrates in the soil
2. Nitrogen-fixing bacteria found in the soil and in the root nodules of leguminous plants, such as peas, beans and clover, fix nitrogen gas into nitrogen compounds
3. The Haber process is used by industry to produce ammonia from nitrogen and hydrogen. Ammonia is used to make nitrogen compounds that are used as fertiliser by farmers.
How are Nitrogen compounds in living things returned to the soil through?
Nitrogen compounds in living things are returned to the soil through:
excretion and egestion by animals
the decay of dead plants and animals.
Denitrifying bacteria present in soil break down nitrogen compounds and release nitrogen gas into the air.
How did life start?
no one was there to record how life began
early Earth was hotter and the atmosphere consisted mostly of carbon dioxide (with other gases such as ammonia and methane).
How old is the earth?
it is not possible to be certain how life on Earth began. We do know that the Earth is about 4,500 million years old