What is the effects of water stress in green plants?

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What is the effects of water stress in green plants? Storage of water in the plant tissues such as leaves Reduction of leaf sizes Loss ... Read More

What is meant by water stress in relation to plants?

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What is meant by water stress in relation to plants? Water stress is a condition in which a plant has a high tendency to lose ... Read More

Ways of keeping the pH in constant in the body.

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Ways of keeping the pH in constant in the body. Buffers such as globular protein  Rate of elimination of carbon dioxide in the lungs Selective ... Read More

Why the pH of the body fluids in human is kept constant.

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Why the pH of the body fluids in human is kept constant.  enzyme work best at optimum pH. pH influences excretion of some toxic substances. ... Read More

With reasons, give examples of animals which produce uric acid  excretory products

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With reasons, give examples of animals which produce uric acid  excretory products Uric acid is secreted by organisms adapted to live in arid areas because ... Read More

ith reasons, give examples of animals which produce ammonia as excretory products

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With reasons, give examples of animals which produce ammonia as excretory products Ammonia is excreted by fresh water animal, e.g. protozoa and hydra, this is ... Read More

What osmotic problem faced by Marine teleost ?

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What osmotic problem faced by Marine teleost  They face a danger of dehydration of their tissues. Explanation: The osmotic pressure of their body fluids is ... Read More

Explain the osmoregulatory problems fresh water teleost?

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Explain the osmoregulatory problems fresh water teleost? They face a danger of dilution of their tissues. The osmotic pressure of their body fluids is higher ... Read More

How do halophytes overcome the problem of physiological draught?

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How do halophytes overcome the problem of physiological draught? Tolerant tissue Secreting salt from salt glands can reduce the salt level in certain halophytes. In other cases, the salt is compartmentalized in certain tissues ... Read More

What physiological problems do they face halophytes?

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What physiological problems do they face halophytes? osmotic loss of water Please Subscribe to promote this website. Subscription is free Share with a friend Thank ... Read More

Give advantages and disadvantage of Marine invertebrates having body fluids which have the same solute concentration as seawater.

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Give advantages and disadvantage of Marine invertebrates having body fluids which have the same solute concentration as seawater. Advantage They do not spend energy in ... Read More

Give one example of a human abnormality caused by a gene mutation

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Give one example of a human abnormality caused by a gene mutation Sickle cell anemia Please Subscribe to promote this website. Subscription is free Share ... Read More

What are Pre-zygotic isolation mechanism or barriers to formation of zygote?

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Pre-zygotic isolation mechanism or barriers to formation of zygote. Seasonal isolation: occurs where two species mate or flower at different time of the year, e.g., ... Read More

What are Post-zygotic isolation mechanism (barrier affecting hybrid)?

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Post-zygotic isolation mechanism (barrier affecting hybrid) Hybrid inviability: Hybrid are produced but fail to develop to maturity. E.g., hybrid formed between northern and southern race ... Read More

With examples explain what is meant by a mutagen.

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With examples explain what is meant by a mutagen Mutagen is a substance that cause mutation Examples of mutagens are mustard gas, caffeic acid, colchine ... Read More

Describe the major types of gene mutation

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Describe the major types of gene mutation Substitution; one or more nucleotide is replaced with a different organic base in a gene Insertion/addition: one or ... Read More

How does the existence of homologous structures in present day vertebrates support the theory of organic evolution?

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How does the existence of homologous structures in present day vertebrates support the theory of organic evolution? Homologous structures are those which have the same ... Read More

What do you understand by the term speciation?

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What do you understand by the term speciation? Speciation is the development of new species from pre-existing one Please Subscribe to promote this website. Subscription ... Read More

What evidences is there to show that DNA is hereditary material?

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What evidences is there to show that DNA is hereditary material? chromosome analysis shows that chromosomes are made up of DNA and proteins only and ... Read More

Explain how the gene frequency of a population may be altered

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How gene frequency of a population may be altered There is non-random breeding. In such cases sexual selection occurs whenever the presence of one or ... Read More

What is meant by reproductive isolation?

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What is meant by reproductive isolation? Reproductive isolation involves failure of interbreeding among organisms of  population. This may be as a result of lack of ... Read More

What is genetic isolation?

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Genetic isolation Genetic isolation occurs when mating can occur but fertilization is not possible and/or even when it occurs, the product is a sterile or ... Read More

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What is the role fertilization in natural selection During fertilization, genes from different parents are mixed independently in different combinations. This introduces variation in the ... Read More

Describe the role of meiosis in natural selection

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Describe the role of meiosis in natural selection During prophase I of meiosis, crossing over occurs between homologous chromosomes and exchange of chromosome segments occurs. ... Read More

Describe the role of  mutation in natural selection

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Describe the role of  mutation in natural selection Mutation changes the nature of genes in an organism and causes inheritable variations. The altered genetic material ... Read More

Explain how humans influence the evolution of species?

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Explain how humans influence the evolution of species? Through artificial selection Human beings are able to select and allow breeding of animals or plants with ... Read More

How can the genetic equilibrium of a population be upset?

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How can the genetic equilibrium of a population be upset? When there is non-random mating; this increases the likelihood of some alleles in the population ... Read More

What is meant by genetic drift ?

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What is meant by genetic drift? Genetic drift is a change in the genetic makeup of a population which occurs by chance (random) events rather ... Read More

What is the role of mutation in evolution of new species

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What is the role of mutation in evolution of new species Mutations are essential to evolution because it introduces genetic variations in a population that form a ... Read More

How does the modern view on evolution differ from Darwin’s View?

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How does the modern view on evolution differ from Darwin’s View? Darwin’s view explains evolution by inheritance of acquired variations which are favored by natural ... Read More

State three observations and two deductions from which Darwin derived this theory

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State three observations and two deductions from which Darwin derived this theory Observation 1; Individuals within a population have a great reproduction potential, e.g., American ... Read More

What may cause a gene pool of a population to be static?

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What may cause a gene pool of a population to be static? Gene pool remain static when there is no mutation, genetic drift, immigration, emigration ... Read More

What is a gene pool?

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What is a gene pool? A gene pool is the stock of different genes in an interbreeding population Please Subscribe to promote this website. Subscription ... Read More

What is the importance of natural selection?

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Importance of natural selection - organisms that are best adapted to a particular environment are allowed to survive and reproduce - population size of a ... Read More

How does natural selection occurs?

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How does natural selection occurs? Because resources are limited in nature, organisms with heritable traits that favor survival and reproduction will tend to leave more ... Read More

What is natural selection?

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What is natural selection? Natural selection the process whereby organisms better adapted to their environment tend to survive and produce more offspring. Please Subscribe to ... Read More

How do homologous structures  give evidence of evolution?

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How do homologous structures  give evidence of evolution? Presence of structures with the same basic plan or fundamentally similar in different organism, though, modified to ... Read More

How do adaptive radiation give evidence of evolution?

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How do adaptive radiation give evidence of evolution? Presence of  homologous structure which have been modified to perform different functions in apparently similar organisms to ... Read More

State the ecological importance of adaptive radiation

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State the ecological importance of adaptive radiation It enables organisms with the structures to exploit different ecological niches hence reduce competition. Please Subscribe to promote ... Read More

Using examples give the meaning of adaptive radiation of species.

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Using examples, give the meaning of adaptive radiation of species? It is specialization of homologous structures to serve different functions. For example, the fore limbs ... Read More

How may nonrandom mating lead to speciation?

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How may nonrandom mating lead to speciation? Nonrandom mating or sexual selection occur naturally when the presence of heritable characteristic increases the likelihood of bringing ... Read More

How may genetic drift lead to speciation?

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How may genetic drift lead to speciation?   Genetic drift is a mechanism of evolution in which allele frequencies of a population change over generations ... Read More

How does resistance of malarial parasite to antimalarial drugs occur?

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How does resistance of malarial parasite to antimalarial drugs occur? Failure of the parasite to absorb the drug Formation of inaccessible forms during its development ... Read More

Explain how constancy of species may be maintained through natural selection

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Species in a population show variation in characteristic. These act as the basis for genes of the next generation. Individuals with characteristic favored by the ... Read More

What is the importance of variation in a population?

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Importance of variations in the population – May lead to emergence of new species. - Increased chances of organisms to survive in different habitats. -Increased ... Read More

In what way may variation resulting from gene reshuffling differ from that caused by mutation?

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  New allele recombinations in one generation may be reversed in the following generations while variations due to mutation are permanent. Gene reshuffling  does not ... Read More

Outline the causes of gene reshuffling

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Causes of gene reshuffling Crossing over prophase 1 in meiosis Independent assortment at metaphase 1 of meiosis Random fusion of gametes from two parents during ... Read More

 State four conditions Hardy- Weinberg equilibrium principle 

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Conditions Hardy- Weinberg equilibrium principle  No mutation occurs Mating must be random The population must be large. No emigration No immigration from or into the ... Read More

Explain the meaning of the Hardy- Weinberg equilibrium principle

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Hardy- Weinberg equilibrium principle Provided there are no disruptive influence such as mutations or selection, the frequency of alleles in a population remains constant, generation ... Read More

Explain why it is difficult to eliminate recessive alleles from a population

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Reasons why it is difficult to eliminate recessive alleles from the population (i) A large proportion of the recessive alleles in a population exist in ... Read More

Explain how does  small population size may alter the gene frequency

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Explain how does  small population size may alter the gene frequency In a small population genetic drift is common because not all the allele which ... Read More

Explain how   closeness of population may alter the gene frequency

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Explain how   closeness of population may alter the gene frequency Gene flow occur between closely related population as a result of interbreeding between members of ... Read More

Distinguish between hybrid and hybrid vigour

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Differences between hybrid and hybrid vigour A hybrid is an offspring of a cross between two closely related but genetically distinct populations. A hybrid vigour, ... Read More

Briefly describe the lock and key hypothesis of enzyme action

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Lock and key hypothesis The enzyme’s active side and its substrate have complementary structure. The enzyme randomly binds with the substrate to form enzyme-substrate complex ... Read More

Differences between enzyme and catalyst

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Differences between enzyme and catalysts   Enzymes Catalysts 1. proteins in nature inorganic chemicals e.g. Pt 2. catalyze specific reactions Such as hydrolysis of starch ... Read More

What is a noncompetitive inhibitor?

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Noncompetitive inhibitor A substance with the structure different from that of the substrate irreversibly binds on the enzyme at a point different from the active ... Read More

What is meant by competitive inhibition?

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 Competitive inhibition - Substances structurally similar to enzyme substrate compete with enzyme substrate for active site on the enzyme molecule where both reversibly bind. - ... Read More

State the dangers of parasitic mode of life

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The dangers of parasitic mode of life Failure to find a host Failure to penetrate a host Failure to protect itself from host defense mechanisms. ... Read More

Why is a tape worm a successful parasite?

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Why is a tape worm a successful parasite possesses suckers and hooks for attachment produces a lot of mucus that protects it from the host ... Read More

Outline the importance of population size in different organism in a given area to ecologist

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Importance of population size in different organism in a given area to ecologist. It enables construction of food chains and webs, pyramid of numbers, biomass ... Read More