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90 Cards in this Set
- Front
- Back
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What are the two types of reproduction? |
sexual and asexual |
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What is sexual reproduction? |
The fusion of the male and female gametes to form a new embryo |
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What is asexual reproduction? |
No fusion of gametes Only one individual is needed as the parent There is no mixing of genetic information There is no genetic variation The new individual is know as a clone |
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what is one way in which asexual reproduction is used to produce plants. |
By taking cuttings from a plant |
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What is tissue culture? |
Using small groups of cells from part of a plant |
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What is an embryo transplant? |
The splitting apart of cells from a developing animal embryo before the become specialized and then transplanting the identical embryos into the host mothers |
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What is adult cell cloning? |
The nucleus from an egg cell is replaced with the nucleus from and adult body cell.An electric shock causes the egg cell to divide to form embryo cells. The embryo further develops into a ball of cells and is inserted in the the womb of an adult female. |
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What happens in genetic engineering? |
The genes from the chromosomes of humans and other organisms are cut out using enzymes and transfered to cells of other organisms. |
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What can scientists do to produce animals plants or micro-organisms with desired characteristics? |
Transfer the genes to their cells |
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New genes can be transfered to crop plants, what are these type of crops called? |
Genetically modified (GM) crops |
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Give some examples of one genetically modified crops |
Herbicide resistant crops Insect attack resistant crops |
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What is one advantage having genetically modified crops? |
They generally show an increased yield |
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What are some concerns about GM crops? |
The effect on population of wild flowers and insects Uncertainty about the effects of eating GM crops on human health |
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How do genes work? |
They operate on a molecular level to produce characteristics that can be seen |
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Define Homozygous and Heterozygous |
Homozygous is having two of the same alleles Heterozygous is having two different alleles |
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Differences in characteristics of different individuals of the same species may be caused. Explain how? |
Different genes inherited Developing in different conditions Or a combination of both |
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State Charles Darwin's theory of evolution by natural selection |
Evolution occurs due to random mutation and all living things have evolved from simple life forms that first developed more than three billion years ago. |
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Why was this theory only accepted gradually? |
The theory challenged the idea the god made all living things on earth There was insufficient evidence at the time The idea of inheritance and variation was not known until 50 years after the theory was published |
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State Jean Lamarck's theory of evolution |
It was the idea that the changes made to an organism during its lifetime can be inherited. |
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Why was this theory wrong ? |
The changes were not made on a molecular level, and therefore could not be inherited. |
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How do we classify organisms? |
By studying the similarities between organisms |
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Why does variation occur? |
Due to differences in the genes that are inherited |
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What is likely to happen to individuals with characteristics most suited to their environment? |
They are more likely to survive and breed more successfully |
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What may happen to a species if a new form of gene results from rapid mutation? |
There may be relatively rapid change in the species is the environment changes aswell |
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When do the materials that are removed from the environment by living things return to the environment? |
When the living things die |
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Why do materials decay? |
They are broken down (digested) by micro-organisms |
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In what conditions are micro-organisms most active? |
In warm, moist and aerobic conditions |
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What happens to the rate of decay when micro-organisms are more active? |
It increases |
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What is one advantage for plants of the decaying process? |
It releases substances that plants need to grow |
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What happens in a stable community? |
The processes that remove the materials are balanced by processes that return materials and thus, the materials are constantly cycled |
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How is carbon dioxide removed from the environment? |
It is removed by green plants and algae for photosynthesis |
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What is that carbon then used for? |
To make carbohydrates, fats and proteins which make up the body of the pants and algae |
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What happens when green plants and algae respire? |
Some of the carbon becomes carbon dioxide and is released into the atmosphere |
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What happens when plants, algae and animals die? |
The micro-organisms feed on their bodies |
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What happens when the micro-organisms respire? |
Carbon is once again released into the atmosphere as carbon dioxide |
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What do micro-organisms do? |
they break down the waste products and dead bodies of organisms and cycle them as plant nutrients. |
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What happens to the energy originally absorbed by green plants and algae |
The energy has been transfered to the plant nutrients |
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What else (apart from the dying and respiration of plants algae and animals), releases carbon dioxide into the atmosphere? |
The combustion of wood and fossil fuels |
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How can we find out what happens to energy and biomass as it passes along a food chain? |
By observing the numbers and sizes of the organisms in food chains |
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Give one source of energy for most living organisms |
Radiation from the sun |
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In what process does the transfer of light energy to chemical energy occur? |
Photosynthesis |
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Where is this energy stored? |
In the substances that make up the cells of the plants |
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What is biomass? |
The mass of living material |
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What happens to the biomass as we go through each stage of the food chain? |
it decreases |
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Why is the biomass in each stage less than the previous stage? |
Materials and energy is lost in the organisms waste When the organisms respire, energy is supplied for movement,some of which is lost into the surroundings |
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What factors can influence population size? |
Competition predation disease Human influences |
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What can changes in the environment affect? |
The distribution and behavior of organisms |
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What do organisms require to survive and reproduce? |
A supply of materials from their surroundings and from other living organisms |
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What 4 things do plants compete for? |
Light Space Water Nutrients |
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What 3 things do animals compete for? |
Food Mates Territory |
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What is the term for when an organism changes in order to survive in the conditions in which they normally live in? |
Adaptation |
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What is the term for an organism that is suited to survive in extreme conditions? |
Extremophiles |
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Give some examples of the conditions that extremophiles can tolerate |
High salt concentrations High temperature High pressures |
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Name some conditions in which animals and plants may be adapted for survival where they normally live? |
Desert Arctic |
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In what ways may animals adapt to survive in dry and arctic environments? |
Changes to surface area Changes to thickness of insulating coat Changes to body fat levels Camouflage |
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In what ways may plants adapt to survive in dry environments? |
Changes to surface area (especially in the leaves) Water storage tissues Extensive root systems |
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In what other ways may animals and plants be adapted to cope with specific features of their environment? |
With the use of thorns, poisons and warning colors to deter predators |
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Give an example for when a change in the environment might affect the distribution of living organisms |
The distribution of some bird species The disappearance of pollinating insects (bees) |
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What living and non-living factors may be considered as a change in environment? |
Change in competitor Average rainfall or temperature |
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What is the term for a group of organisms that are used to detect pollution in the environment? |
Indicator species |
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Give some examples of indicator species |
Lichens Invertebrate animals |
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What type of pollution are lichens used to detect? |
Air pollution (particularly sulphur dioxide levels in the atmosphere) |
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What type of pollution are invertebrate animals used to detect? |
Water pollution (particularly concentrations of dissolved oxygen in water) |
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In what way can environmental changes be measured in? |
Oxygen levels Temperature Rainfall |
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Why are medical drugs made? |
To relive illness or disease |
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Why may drugs be used recreationally? |
Some people like the effect they have on the body |
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Why may some drugs be addictive? |
They change the body's chemistry as well as causing the user to form a dependancy on them |
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Why may some athletes take drugs? |
To improve their performance |
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Why may a person not make a sensible decision about drugs? |
They may not know the full effects of the drug |
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Why do drugs have to be tested extensively? |
To test for efficiency,a safe dose side effects, toxicity and efficacy |
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What was thalidomide originally developed as? |
A sleeping pill |
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What is Thalidomide used to treat nowadays? |
Bone/blood cancer and Leprosy |
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Why was thalidomide banned? |
It was found out that its caused limb abnormalities in the babies of pregnant women |
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Before it was banned, what else was thalidomide used to treat? |
Morning sickness in pregnant women |
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How are we able to predict how drugs will behave on humans? |
We test the drugs on tissues and animal models |
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What is a double blind trial? |
A trial where neither the patient or the doctor knows whether the patient is receiving a placebo or not |
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Why do we use double blind trials? |
So the results are not biased |
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What does a statin do? |
It lowers the risk of heart and circulatory diseases |
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What is cannabis? |
It is an illegal drug |
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What are the side effects of cannabis? |
It may cause mental illness in some people |
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Why is the overall impact of legal drugs (both prescribed and non-prescribed), on health much greater than the impact of illegal drugs? |
More readily available Easier to obtain More people use them |
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Give an example of both a legal and illegal drug that can have a great impact on our health if misused |
Alcohol and paracetamol |
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What do drugs in general do to peoples' bodies? |
It changes the chemistry of the body, causing the user to form a dependancy on the drug |
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What may the user suffer from without the drug once he has formed a dependancy? |
Withdrawal symptoms |
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Give an example of some recreational and addictive drugs |
Heroin and Cocaine |
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What type of drugs may an athlete take to enhance their performance? |
Stimulants and anabolic steroids |
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What do stimulants do to the body? |
They increase the rate of bodily functions such as the heart rate |
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What do steroids do to the body? |
They stimulate muscle growth |
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What do the CNS and hormones do? |
It enables us to be able to respond to external changes and to control conditions inside our bodies |
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What are hormones used in? |
Some forms of contraception and in fertility treatments |
