B2 Flashcards
What is the order of the groups of classification?
1) Kingdom
2) Phylum
3) Class
4) Order
5) Family
6) Genus
7) Species
What happens to the number of organisms in each group as you go down the list? (Towards Species)
As you move down the groups the number of organisms in each group will get smaller?
What are the two systems of classification?
1) Natural Classification.
2) Artificial Classification.
How does the artificial system of classification work?
It is a way of grouping organisms based on their physical traits.
How does the natural system of classification work?
The natural system is based on evolutionary relationships, animals which are closely related are in the same group.
How can scientists tell how closely together organisms are related?
Scientists can compare the DNA of organisms, to see how similar they are.
What is a species?
A species is a group of organisms which can interbreed to produce fertile offspring.
What is the current classification system called?
The current classification system is called the binomial system.
How does the binomial system work?
The binomial system splits the into two parts, the genus, and the species. The first name is the genus and the second is the species.
What is the main difficulty with classifying organisms?
Some organisms can be put into multiple groups along with the discovery of new organisms.
What is the main issue with classifying organisms by species?
Bacteria produce asexually so they can not be classified as a species.
What is a Hybrid organism?
A Hybrid organism is one which is produced through interbreeding of two different species. They can not produce fertile offspring.
What is an example of a Hybrid organism?
A Donkey is a common example of a Hybrid.
What do organisms in the same group normally have in common?
They normally share a common ancestor.
What are the two type of pyramids used to represent biological environment?
1) Pyramid of number.
2) Pyramid of biomass.
What is shown in a pyramid of biomass?
A pyramid of biomass represents the dry mass of living material at each stage in a food chain.
What is shown in a pyramid of number?
The number of organisms at each level in a food chain.
What two factors may cause a pyramid of biomass to look different to a pyramid of number?
1) If a producer has a very large mass.
2) If a small parasite lives on a large animal.
Why are Pyramids of biomass difficult to construct? (Two Reasons)
1) Some organisms feed on organisms from different trophic levels.
2) Dry mass involves killing the organism.
What three things can energy be wasted on when transferring energy between trophic levels?
1) Respiration.
2) Egestion.
3) Excretion.
What happens to the wasted energy between trophic levels?
It can be used by decomposers to start a new food chain.
What is the average percentage of lost energy between trophic levels?
90% is the amount lost normally between each level in a food chain.
What is the equation for efficiency between animals in a food chain?
energy useful / total energy * 100
What are the basic steps involved in the Carbon Cycle?
1) Carbon dioxide is removed from the air by plants.
2) Burning fuels and respiration releases carbon dioxide into the air.
3) Carbon dioxide is absorbed from the air by oceans
What are the basic steps of the Nitrogen Cycle?
- Nitrogen in the air coneverted into nitrates in the soil.
- Decomposers break down proteins in rotting plants and animals, into ammonia.
- Nitrifying bacteria turn ammonia in decaying matter into nitrates.
- Nitrogen-fixing bacteria turn atmospheric N2 into nitrogen compounds plants can use.
- Denitrifying bacteria turn nitrates back into N2 gas.
What is the role of Decomposers in the Nitrogen cycle?
To convert proteins into ammonia.
What is the role of Nitrifying Bacteria in the Nitrogen cycle?
Nitrifying Bacteria convert ammonia into nitrates.
What is the role of Denitrifying Bacteria in the Nitrogen cycle?
Denitrifying Bacteria converts nitrates into nitrogen gas.
What two conditions do decomposers need to keep working?
1) Oxygen
2) A suitable PH
When does competition occur between organisms?
Competition occurs between similar species in the same habitat.
What is an example of a resource competition may occur over?
Competition occurs around resources such as food or water.
What are the two types of competition?
1) Interspecific competition.
2) Intraspecific competition.
What is interspecific competition?
Interspecific Competition occurs between organisms of different species.
What is intraspecific competition?
Intraspecific competition occurs between organisms of the same species.
Which type of competition is the most significant?
Intraspecific is the most significant as similar organisms share the same resources, leading to more competition.
What is the reason that causes the numbers of predator and prey to fluctuate?
When there is lots of prey more predators survive, causing an increase in numbers, this causes the number of prey to decrease. Although because of this the predators starve so the number declines, before the number of prey increases again as there are not as many predators.
What is mutualism?
Mutualism is a relationship in which both organisms benefit.
What is parasitism?
Parasitism is when one organism benefits (parasite ) but at the cost of the other (host).
Give an example of mutualism.
Cleaner fish remove parasites from larger fish, in return the cleaner fish gains food.
What is an example of Parasitism?
A tapeworm living inside of another organism.
How are some animals adapted to living in very cold conditions?
- Insulation to prevent heat loss. - They have a low surface area to volume ratio. - Changing behaviors. e.g. Migrating to warmer areas and hibernation. - Counter-current heat exchange systems. - Biochemical adaptations. e.g. antifreeze proteins in cells.
How do counter-current heat exchange systems in Penguins work?
Warm blood entering the flippers warms up the cold blood leaving, to stop it cooling the body.
How are some animals adapted to living in hot conditions?
- Large surface area to volume ratio. e.g. Large ears increase surface area. - Changing behaviours. e.g. Panting and licking fur. - Movement behaviours. e.g. Some animals may seek shade during the hotter hours of the day.
How are camels adapted to living in hot and dry environments?
- They produce very concentrated urine to prevent water loss. - They have very little hair on the underside of their bodies to increase heat loss.
How are cacti adapted to living in dry environments?
- Leaves are spines to prevent water loss. - Deep roots so it can absorb as much water as possible. - Can store water in the stem.
How can some bacteria live in hot springs with temperatures as high as 100°C?
They have enzymes that do not denature at high temperatures.
What are specialists?
Organisms that are well adapted to living in specific habitats and would struggle to live elsewhere.
What are generalists?
Organisms that can live in several habitats, however will lose to specialists in certain habitats.
Describe the process of natural selection
-Within any species there is variation -Organisms produce lots of young, lots of which may not survive. There is competition for limited resources such as food. -Only those that best adapted will survive (survival of the fittest). -Those that survive pass on their genes to the the next generation which can contain successful adaptations
What is a species defined as
when the organisms can mate and produce fertile offspring, they are the same species. When they cannot, they are no longer the same species.
How can natural selection produce a new species?
If a group of species was split into two, the groups may, over time, become different enough to be classed as a different species
What sort of factors can cause a group of species to separate into two or more groups?
Geographical isolation - they live in different areas and so they cannot mate Behavioral isolation - The two groups behave differently, meaning they are prevented from mating
describe two modern examples of natural selection
-More and more bacteria are developing resistance to antibiotics -peppered moths are dark or pale in colour. Dark moths are better camouflaged in polluted areas, so more of them survive.
What was Lamarck’s theory?
The law of acquired characteristics said, for example, that giraffes acquired long necks to feed, and this characteristic was passed on. The theory was proven incorrect.
Why did people disagree with Darwin’s ideas at first?
-Some thought he lacked in evidence -Many disagreed as they thought God had created all species.
What are the different types of pollution?
-carbon dioxide, from burning fossil fuels, may increase greenhouse effect and global warming. -CFC’s from aerosols, destroy the ozone layer. -sulfur dioxide from burning fossil fuels causes acid rain.
what is the amount of pollution caused per person or organisation called
Carbon footprint
where is the greatest rise in population figures occurring?
in under-developed areas, such as Africa and India
What is exponential growth?
The name given to the growth rate of human population currently. It is growing at an ever increasing rate.
How can we measure the pollution in water or air
By using direct methods or by indicator organisms
What do direct methods include?
-oxygen probes attached to computers that measure the exact levels of oxygen in a pond. -Special chemicals can be used to indicate levels of nitrate pollution from fertilisers.
How can the presence or absence of an indicator species be used to estimate pollution levels?
-The mayfly larva can only live in clean water -The water louse, bloodworm and mussels can live in polluted water -Lichen grows on trees and rocks but only where the air is clean.
What is the advantage of using indicator species
it is cheaper, doesnt require equipment that can go wrong, monitors pollution levels over long periods of time
what is the advantage of using direct methods of measuring pollution
Can give more accurate results at any specific time
What is conservation?
An attempt to preserve the variety of plants and animals and the habitats that they live in.
Why is conservation important?
- protect our food supply -prevent any damage to food chains, which can be hard to predict -protect plants and animals that might be useful for medical uses - protect organisms and habitats that people enjoy to visit and study.
What are species at the risk of if their levels drop below critical levels?
Species are at risk of extinction if the number of individuals or habitats falls below critical levels.
What four factors need to be considered while trying to conserve a species?
-the size of the population (if the population is below a critical level there is unlikely to be enough genetic variation in the population to enable it to survive) -the number of suitable habitats that are available for the organism to live in - how much competition there is from other species.
Why is it important that whales are conserved?
Whales have been hunted for several hundred years as their body can be used to make many products. Live whales are also a tourist attraction.
Why might whales be in captivity?
1) For captive breeding 2)Research 3)Entertainment.
What issues might whale captivity cause?
Many people object to the whales being in captivity.
Why is it difficult to conserve whales?
it has been difficult to set up and police international agreements on whaling and some countries want to lift the ban on whaling.
What is sustainable development?
Sustainable development means taking enough resources from the environment for current needs, while leaving enough for the future and preventing permanent damage.
What are two examples of sustainable development?
- Fishing Quotas - Responsible cutting of trees
Why is it important to use fuel responsibly?
Because soon fossil fuels will run out, so we must manage alternate energy sources.
Why is it important to grow food responsibly?
We need to supply increasing amounts of food for growing populations without destroying large areas of natural habitats.
Why is sustainable development important?
It should help to save endangered species.
