Tag: Dr. Bbosa Science
Adaptations of a respiratory surface.
It must be permeable, so that gases can pass through. It must be thin, because diffusion is only efficient over distances of 1mm or less. ... Read More
Detection of movement and posture of the body by the vestibular apparatus of the ear
The vestibular apparatus The vestibular apparatus responsible for the sense movements in body and maintenance of dynamic equilibrium, consists of three semicircular canals in planes ... Read More
How frequence is detected by the ear/How the ear distinguishes the frequencies of sound
The analysis of sound frequencies by the basilar membrane. The fibres of the basilar membrane become progressively wider and more flexible from the base of ... Read More
The process of hearing
Sound waves impinge on tympanic membrane that vibrate accordingly. The movement of the tympanic membrane are transmitted by the three ossicles to the oval window ... Read More
Similarities and differences between human and compound eyes
Similarity both have lenses have light sensitive cells allow eye to collect data that is interpreted by brain to form images Differences Character Human eye ... Read More
What is precision/visual acuity of the eye?
The ability of the eye to distinguish between two distant points as distinct points is called precision/visual acuity. Visual acuity is due to cones. ... Read More
Why rods are more sensitive to light than cones
Rods are more sensitive to light than cones because their photochemical pigment of rods responds to very low light intensities. Numerous rods make synaptic contact ... Read More
Transduction of light in the retina
(i) Photo-transduction is the process in which light is converted into electric signal in rods and cone cells of the retina. (ii) Both rod and ... Read More
Importance of mutual or lateral inhibition in the eye
Mutual or Lateral inhibition This occurs when the activity of one cell suppresses the activity of a nearby cell or when activation of one cell ... Read More
Differences between rods and cones
Rods Cones Outer segment rod shaped Outer segment cone shaped Rods occur in large number Concentrated in fovea Have low visual acuity Have high visual ... Read More
Adaptation of desert frogs to desert condition
An adaptation is a physical or behavioural change that an animal or plant possesses to help it cope with its environment. Here are some of the ways ... Read More
How mammals living in arid areas overcome the problem of water shortage.
How mammals living in arid areas overcome the problem of water shortage. Note the key words are bolded Camel excretes high uric acid content to reduce ... Read More
Role of Kidney in pH control
Proteins, hydrogen carbonate and phosphate buffers in blood prevent excess hydrogen ions (H+), produced by metabolic activities from decreasing the pH of blood. Carbon dioxide ... Read More
Isolation mechanisms in evolution
An isolating mechanism is a mean of producing and maintaining isolation within a population. This can be brought about by mechanisms acting before or after ... Read More
How migration affects genotype frequencies
Introduces more copies of genes in the population increasing the proportion of certain gene the population Introduces new genes in the population that have risen ... Read More
Heterozygotes as a reservoir of genetic variation (the Hardy-Weinberg principle)
For a particular character in a population, the dominant form expresses itself more often that a recessive form, for example normal skin color is more ... Read More
Gene flow-meaning
It’s the movement of alleles from one population to another as a result of interbreeding between members of the two population. Please find free downloadable ... Read More
Genetic load-meaning
This is the existence within a population of disadvantageous alleles in heterozygous genotype e.g. sickle cell trait in region where malaria is endemic. Please find ... Read More
Genetic drift-meaning
This refers to the fact that variation in gene frequencies with populations can occur by chance rather than by natural selection. E.g., chance events such ... Read More
Genotype frequency-meaning
This is the fraction of organisms in a population carrying a particular genotype. The frequency of dominants and recessive allele in a population will remain ... Read More
Allele frequency
This the fraction of organisms in a population carrying a particular allele. Please find free downloadable notes, exams and marking guides of agriculture, biology, and ... Read More
Gene pool-meaning
A gene pool is the stock of different genes in an interbreeding population Please find free downloadable notes, exams and marking guides of agriculture, biology, ... Read More
Current Examples of direction selection in ecology
The gradual increase in size of a modern horse with change in environment from forest-like condition to grass land conditions. Industrial melanism; the gradual increase ... Read More
Importance of natural selection
- organisms that are best adapted to a particular environment are allowed to survive and reproduce - population size of a given environment is regulated ... Read More
Types of variations in organisms
Variation. The term variation describes the differences in characteristics shown by organism belonging to the same natural population or species. Types of variation Continuous ... Read More
The categories of enzymes
The categories of enzymes are Oxidoreductase; are involved in biological oxidation and reduction reaction. They include dehydrogenase which catalyze removal of hydrogen atoms from a ... Read More
Difference between enzyme and catalysts.
Enzymes Catalysts 1. proteins in nature inorganic chemicals e.g. Pt 2. catalyze specific reactions Such as hydrolysis of starch may catalyze more than ... Read More
Parasitic adaptations
Parasite show many different adaptations of overcoming these challenges, depending on whether they are ecto-parasites or endo-parasites. Many endoparasites show degeneration, or even total loss ... Read More
Environmental resistance in ecology
The form that the environmental resistance takes depends on the species in question. Here are the main factors that limit population growth lack of food ... Read More
Factors that affect the size of the population
The number of individuals in a population is affected by four factors; birth, deaths, immigration and emigrations. The change in the size of any population ... Read More
Precautions for capture-recapture methods
Organisms mix uniformly within the population. Sufficient time elapsed between capture and recapture to allow uniform mixing. The population is closed, i.e. there is no ... Read More
Factors to be considered to select a method to be used.
Size of the organism e.g. big organisms such elephants are easily counted directly Mode of the organism such as motility; plants and sessile or slow-moving ... Read More
Importance of estimating the population size
To be able to construct food webs and chains, pyramid of numbers, biomass and energy To understand the existing food relationship within a habitat. To ... Read More
Evidences that DNA is the hereditary material
1. DNA is a stable molecule The amount of DNA in a given species is constant for all cells. Mutation or changes in the ... Read More
The impulse-meaning
An impulse or action potential is a temporary and local reversal of the resting membrane potential, arising when an axon is stimulated. Please find free ... Read More
Systems responsible for maintenance of the acid-base balance or pH
Several systems maintain constant pH. The list below is made according to order when they act: 1) Chemical buffering systems provides immediate and short-term response ... Read More
Differences between mitochondria and chloroplasts
Chloroplast Mitochondria Structural difference 1. Contain chlorophyll Does not contain chlorophyll 2. Inner membrane form grana Inner membrane folded to form cristae 3. May contain ... Read More
Similarities between mitochondria and chloroplasts
Both have double membrane, circular DNA Inner membrane is folded to increase the surface area Contain ATPase enzyme for ATP synthesis Both occur in plant ... Read More
Adaptations of mitochondria to its function
The inner membrane is folded to form cristae that increase surface area for enzymatic activities. Contains circular DNA to produce the necessary enzymes. Has a ... Read More
The fluid mosaic model of the cell
The cell membrane is about 7nm thick It consists of a continuous phospholipid bilayer in which proteins are scattered in a mosaic manner. Proteins penetrate ... Read More
Advantages of membrane bound organelle
Many metabolic processes involve enzymes embedded in membranes, so the membrane bound organelles increase the surface area for activities like respiration and photosynthesis. Maintain enzymes ... Read More
Differences between active transport and osmosis
Osmosis Active transport Does not require energy Requires energy Transport water Transport sugars, ions and salts Does not require carrier proteins Requires carrier proteins Does ... Read More
Functions of active transport
Absorption of minerals in the stomach Absorption of minerals in ascending loop of Henle Absorption of mineral in the root hair from the soil Entry ... Read More
Evidence for active transport in living organism
It is only found in living system which are continuously producing energy by respiration. Increase in temperature and oxygen concentration increases the rate of active ... Read More
Effects of osmosis on animal cell e.g. Red blood cell
A solution of 0.9% sodium chloride is isotonic with human cells, and if red blood cells are immersed in isotonic solution, they will neither swell ... Read More
Differences between mitosis and meiosis
Mitosis meiosis 1. Homologous chromosomes remain separate Homologous chromosomes pair up 2 There no crossing over Crossing over occurs 3. No formation of chiasmata ... Read More
Significance of meiosis
Sexual reproduction: Meiosis results in half the number of chromosomes, during fertilization the nuclei of the two gametes fuse to form a zygote restore the ... Read More
Importance of mitosis
Genetic stability: It ensures that the daughter cells carry the exact genetic material as the parent cells Growth: growth results in increase in the number ... Read More
Advantages of migration behaviors-biology
Return to specialist site for breeding that does not need all year round food supply, and often no (or few) predators. Move to where food/prey ... Read More
Disadvantages of group/social behaviours
Competition for food Competition for male and some monopolize female. Intraspecific competition may be a means of regulating population size Reduces individual’s chances of being ... Read More
Importance/Advantages of social behavior
Species in large groups suffer less predators even when the predator is successful; The chance that one is picked is very low. Predators are more ... Read More
Importance of displacement activity
It may be away of releasing stress Please find free downloadable notes, exams and marking guides of agriculture, biology, and chemistry from digitalteachers.co.ug website. Dr. Bbosa Science Read More
Disadvantage of territorial behaviour
Weak animals are denied sex Limit population density and other good qualities are lost Promote spreading of diseases May lead to extinction in case of ... Read More
Functions of courtship behaviour.
Allows the male mate with female when gonads are functional It enables the mates to select opposite sex with the best quality enabling the community ... Read More
Importance of imprinting behavior
It enables the young animal to recognize its own mother from among the other adults of its species. In early childhood, human become imprinted on ... Read More
Importance of learning
Important for socialization process, as children learn how to behave and respond to others by observing how their parents and other caregivers interact with each ... Read More
Importance of habituation
Enables a young animal to understand neutral elements in the environment such as movements due to wind. It enables an animal to save energy by ... Read More
Ecological importance of taxis
Helps an organism to find food Enables an organism to avoid unfavorable environment. Enable organism to find mates Please find free downloadable notes, exams and ... Read More
Ecological importance of kinesis
It increases the chances of finding resources and favorable conditions by sheer luck. Please find free downloadable notes, exams and marking guides of agriculture, biology, ... Read More
Difference between kinesis and taxis
Kinesis is a random (non-directional) movement in response to a stimulus while taxis is a directional movement away or towards a stimuli. Please find free ... Read More