Download Water in plants and animals

Meiosis
Know and understand the events taking place in mitosis as learned in
standard grade (sites of mitosis, chromatids, movements of chromosomes
and chromatids, chromosome number kept constant).
Know that meiosis is the type of cell division which gives rise to gametes.
Know that it takes place in reproductive organs of plants and animals.
Know that it halves the chromosome number, and understand the terms
haploid and diploid.
Understand the necessity for halving the chromosome number when
gametes are formed.
Understand that the cells produced contain one chromosome from every
homologous pair in the original cell.
Know all the movements of chromosomes and chromatids which take place
during the two divisions of meiosis.
Understand how crossing over and independent assortment of
chromosomes are important sources of variation for a species.
Be able to describe the differences between meiosis and mitosis.
Genetics
Be able to solve problems involving monohybrid crosses as learned in
Standard Grade.
Solve dihybrid cross problems involving:
(i) Working out genotype and phenotype ratios in crosses to the F2
generation.
(ii) Working out the genotypes of parents in a dihybrid cross, when
given information about their offspring.
Understand incomplete dominance and be able to solve problems involving
this type of inheritance.
Know that the two genes in a dihybrid cross may be linked on the same
chromosome, and understand how this limits the range of gametes
produced, and hence the range of genotypes in the offspring.
Given the results of suitable crosses, be able to identify cases where
genes are linked.
Understand how crossing over between linked genes can lead to
recombination of alleles in a cell undergoing meiosis.
Understand that the frequency of crossing over between a pair of linked
genes indicates the distance between them on the chromosome.
Understand how chromosome mapping can be done from crossover
frequencies.
Be able to work out the sequence of several linked genes on a chromosome
when given crossover frequencies.
Know the existence of sex chromosomes and know that the sexes may be
homogametic (XX) or heterogametic (XY).
Know that in humans and Drosophila the male is XY and the female is XX.
Understand how the inheritance of sex chromosomes determines the sex
of offspring in a cross.
Know that sex linked genes lie on the X chromosome.
Be able, using correct symbols, to solve problems on crosses involving sex
linked genes.
Know that a mutation is a sudden change in the genotype of an organism.
Understand how gene mutations involve changes in the bases in the DNA
of which a gene is composed, and be able to describe the various types of
gene mutation (insertion, deletion, inversion and substitution).
Understand how gene mutation leads to changes in phenotype through
alteration to mRNA base sequence and hence altered amino acid sequence
in proteins.
Know some examples of gene mutation e.g. sickle cell anaemia, antibiotic
resistance in bacteria.
Know that chromosome mutations may involve changes in chromosome
number or structure.
Understand how changes in chromosome number may result from
nondisjunction of homologous chromosome pairs during meiosis.
Know some examples of this type of mutation e.g. Down’s syndrome.
Understand how polyploidy can result from total nondisjunction in meiosis
or spindle failure during mitosis.
Understand how polyploidy can result from crosses between closely
related species.
Know advantageous features of polyploid crop plant species.
Be able to describe mutations involving changes in chromosome structure
(deletion of genes, duplication of genes, translocation of genes, inversion
of genes), not confusing these with base changes in gene mutation.
Know that mutation can be spontaneous or induced, and know examples of
mutagens which induce gene and chromosome mutation.
Understand how gene mutation can affect metabolism by altering
enzymes which play key roles in metabolic pathways.
Understand an example of this, e.g. phenylketonuria.
(Unit3)
Selection and Speciation
Know that variation within a species can lead to change.
Know sources of variation (mutation, crossing over, independent
assortment of chromosomes).
Know that natural selection is a mechanism of change.
Understand the following stages in natural selection :
(i)
some variants having a selective advantage, i.e. better suited
to the environment
(ii)
these surviving and having more offspring that others
(iii)
favourable alleles being passed to the next generation
(iv)
frequency of these alleles increasing as a result
Be able to explain examples of natural selection such as industrial
melanism, metal tolerant grasses, antibiotic resistant bacteria,
insecticide resistance.
Understand how the selective advantage of normal or sickle cell
haemoglobin is related to malaria.
Know that Darwin put forward one of the first theories of natural
selection.
Understand how, over a long period of time, natural selection may be an
important mechanism in evolution.
Understand what is meant by artificial selection.
Know that artificial selection and selective breeding have led to the
‘evolution’ of many varieties of domestic animals and crop plants from wild
ancestors, and be able to give examples of this.
Know that crosses between closely related species (hybridisation) has led
to the appearance of new species of agricultural importance.
Know that these are often polyploid and understand (from earlier notes)
how polyploidy occurs.
Know advantageous features of hybrid crop plants.
Know the definition of the term species.
Know that speciation is an evolutionary process whereby one species can
give rise to a number of new species.
Understand why this can only take place if groups within the original
species become isolated from each other.
Know the different isolating mechanisms (geographical, ecological,
reproductive) and know some examples of each.
Understand why isolated groups evolve differently from each other,
eventually becoming distinct species.
Understand how groups which have been isolated for some time are
recognised as subspecies before evolving into separate species.
Understand how several populations are recognised as one species as long
as gene flow through the different populations is possible.
Understand how geographical isolation resulting from migration and
continental drift has led to world wide differences in animal species.
Understand how ‘Darwin’s finches’ may have evolved in conditions of
extreme isolation and lack of competition from other types of birds.
Know that evolution from a common ancestor to a variety of types
occupying different ecological niches is described as adaptive radiation.
Know that species occasionally become extinct, and know some examples
of this.
Know some causes of extinction of species.
Understand how small populations are particularly vulnerable because of
their lack of genetic diversity.
Understand the importance of conserving species and know some steps
which can be taken to avoid extinction.
Know that chromosome mapping involves locating the position of genes on
chromosomes.
Know that when chromosomes are stained, bands are seen which may
represent the positions of different genes.
Understand how genes can be located by correlating different genotypes
with different banding patterns (e.g. in Drosophila X chromosome).
Understand how band changes in individuals with genetic abnormalities
may indicate the positions of faulty genes.
Know that the position of a gene on a chromosome can be located using a
gene probe.
Know that genes can be transferred from one organism to another in the
process of genetic engineering (particularly from human to bacteria).
Know examples of human proteins which can be manufactured by bacteria
as a result.
Know the benefits of manufacturing substances by this method.
Know that genes are cut from human chromosomes and bacterial plasmids
are cut by endonuclease enzymes (also called restriction enzymes).
Know that human genes are inserted into plasmids by ligase enzymes.
Know that cells from different plant species can be joined by somatic
fusion when interbreeding is impossible.
Know an example of this and the benefits that result.
Know the procedure involved in somatic fusion (enzyme digestion of cell
wall by cellulase, protoplasts, fusion).
Obtaining Food (Animals)
Know that foraging is the procedure by which animals obtain food.
Know that foraging involves expenditure of energy for finding prey, killing
prey, eating prey etc.
Know that the energy gained from food must exceed the energy required
for foraging.
Know that in optimal foraging the difference between energy gain and
energy expenditure is maximised.
Know some examples of optimal foraging.
Know that competition occurs when members of a community require the
same resource.
Know the difference between the terms interspecific and intraspecific.
Know that interspecific competition occurs when two species occupy
similar niches.
Understand how the intensity of competition can be reduced when
species adapt so that their niches overlap as little as possible.
Know that where the niches of two species are identical, the more
effective competitor will survive while the other becomes extinct.
Understand why competition for identical resources leads to intraspecific
competition being more intense than interspecific competition.
Understand how behavioural adaptations such as holding territories can
reduce intraspecific competition for food.
Know some examples of animals, which display territorial behaviour.
Know that the territory holding members of a population benefit from
having guaranteed access to limited food resources.
Know methods by which territorial animals mark and defend the
boundaries of their territories.
Know that the size of territory held will tend to increase as food
availability decreases.
Know the benefits of cooperative hunting and some examples of animals
which use cooperative hunting.
Know what a dominance hierarchy is and some examples of animals, which
have this type of social organisation.
Know the benefits of dominance hierarchies.
Know some examples of dominant and subordinate behaviour.
Coping with Dangers (Animals)
Know examples of mechanisms which individual animals use to defend
themselves against predators (escape responses, distraction displays,
chemical defences etc. )
Know that escape responses may be subject to habituation and
understand the benefits of this.
Know that habituation is an example of short term modification of
response.
Know that learning involves longer term modification of responses, where
an animal learns to associate a particular response with a reward.
Know and understand examples of learned behaviour.
Know some examples of social mechanisms by which groups of animals can
defend themselves against attack by predators.
Obtaining Food (Plants)
Know that plants compete for light, water, and soil nutrients.
Know that interspecific and intraspecific competition exist in plant
communities and understand why intraspecific competition is more
intense.
Know some ways in which certain plants are adapted to cope with
competition (including sun / shade adaptations).
Know and understand how the numbers of plant species in a community
are affected by different levels of grazing intensity.
Know that leaf mosaic arrangement is an adaptation to cope with light as
a limiting factor.
Understand what is meant by compensation point.
Know that shade plants have low compensation point and understand why
this is advantageous to them.
Understand how the different pigmentation of shade plants is a useful
adaptation.
Coping with Dangers (Plants)
Know some examples of structural adaptations which deter herbivores
(thorns, spines, stings).
Know how the growth form of some plants allows them to tolerate
continual grazing (grasses, dandelion rosette etc.)
Water in plants and animals
Know the structures and understand the processes involved in uptake of
water by the root and movement of water to the xylem tissue.
Know the structures and understand the processes involved in movement
of water from leaf xylem to the stomata.
Understand the processes involved in movement of water up the stem of
a plant (root pressure, adhesive forces, cohesive forces).
Understand the mechanism by which guard cells control stomatal
aperture.
Know that transpiration is the loss of water from the leaves of a plant.
Know environmental factors which affect transpiration rate and
understand their effects.
Understand the importance of the transpiration stream to a plant.
Know the procedure for measuring transpiration rate using bubble and
mass potometers, including precautions which are necessary to ensure
that accurate results are obtained.
Understand the use of atmometers in transpiration experiments.
Know that osmoregulation is the control of water balance by plants and
animals.
Know that osmoregulation is an example of homeostasis.
Know that homeostasis is the maintenance of constant conditions in an
organism.
Know that plants are classified as mesophytes, xerophytes and
hydrophytes according to their habitat.
Know that xerophytes have xeromorphic features which allow them to
maintain their water balance in dry or windy habitats.
Know and be able to recognise xeromorphic adaptations for reducing
water loss, maximising water uptake, and storing water.
Know the adaptations of hydrophytes which ensure buoyancy and gas
exchange in an aquatic environment.
Know the methods by which a mammal gains and loses water, and that
balance is achieved by controlling urine volume.
Know why it is important that water concentration of the blood and tissue
fluids is maintained within limits.
Know the structure of the human kidney, paying particular attention to
the structure of the nephron.
Understand the working of a nephron in terms of ultrafiltration, followed
by reabsorption of water and required dissolved materials into the blood.
Know that reabsorption of dissolved materials involves energy - requiring
active transport.
Know that the ADH secreted by the pituitary gland stimulates water
reabsorption from the collecting duct at the end of the nephron.
Understand the process by which changes in ADH production keep the
water concentration of the blood stable.
(Unit 3)
Understand the water balance problems faced by freshwater and salt
water fish.
Know the adaptations which allow them to maintain water balance in these
environments (kidney adaptations; chloride secretory cell function).
Know the changes in filtration and chloride secretory cell activity
required when salmon and eel migrate between salt and fresh water.
Know the physiological adaptations to conserve water which are found in
small desert mammals.
Know behavioural adaptations by which small desert mammals conserve
water.