What is variation in biology?
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What is variation in biology?
Variation is defined as differences between individuals in an ecosystem.
Give examples of genetic variation in humans.
Examples of genetic variation in humans include:
blood group
eye colour
biological sex
ability to roll the tongue
free or fixed earlobes
What factors contribute to environmental variation?
Environmental factors such as climate, diet, accidents, culture, and lifestyle contribute to environmental variation.
Give examples of environmental variation.
Examples of environmental variation include:
scarring from accidents
weight gain from diet and lifestyle
language and accent from being raised in a certain country
plant growing taller in the shade to reach more light
How can genes and environment together affect a characteristic?
Genes give the characteristics we inherit, but the environment affects how these inherited characteristics develop.
For example, children of tall parents have the genetic potential to be tall, but poor diet can affect their growth.
What is genetic variation?
Genetic variation refers to differences in the DNA sequences of individuals within a population, leading to different traits or characteristics.
What causes genetic variation within a species?
Genetic variation within a species is usually caused by mutations, which are random genetic changes that occur continuously.
How do most mutations affect the phenotype?
Most mutations do not affect the phenotype because the protein produced by a mutated gene may function just as well as the protein from the non-mutated gene.
Define mutation.
Mutations are random genetic changes that occur continuously.
What influences the development of the phenotype of an organism?
The genome and its interaction with the environment influence the development of the phenotype of an organism.
Define the term evolution.
Evolution is the change that occurs in populations over many generations. Natural selection is the mechanism by which this change occurs. This may result in the formation of a new species.
What does the theory of evolution state about the origin of all living species on earth?
All species of living things have evolved from simple life forms that first developed more than three billion years ago.
Define the term species.
A new species is formed when two populations of one species become so different in phenotype that they can no longer interbreed to produce fertile offspring.
What is selective breeding in plants?
Selective breeding in plants involves the intentional breeding of plants with desirable traits to produce offspring with enhanced characteristics.
What are some characteristics that plants are selectively bred for?
Plants are selectively bred for various characteristics including:
Disease resistance in food crops
The development of large or unique flowers
(The first two you need to specifically for your specification)
Increased crop yield
Tolerance to weather conditions such as drought or frost
Improved taste and nutritional quality of fruits
What are some potential problems associated with selective breeding?
Selective breeding can lead to inbreeding, which occurs when closely related individuals are bred together to perpetuate desired traits.
Inbreeding reduces the genetic diversity within a population, resulting in an increased risk of inheriting harmful genetic defects.
Additionally, the reduced genetic variation makes organisms more susceptible to new diseases, as there are fewer chances of possessing resistance alleles within the population.
What are two potential characteristics that animals are selectively bred for?
Animals are selectively bred for various characteristics, including:
High milk or meat production in livestock such as cows, goats, and sheep
Docile temperament in domestic dogs
(The first two you need to know specifically for your specification)
High-quality wool in sheep
Large egg-laying capacity in chickens
Specific physical features or performance abilities in horses
What is selective breeding in animals?
Selective breeding (also known as artificial selection), involves the intentional mating of animals with desirable traits to produce offspring that inherit those characteristics.
Through careful selection and breeding of animals over successive generations, breeders aim to develop new breeds or strains that reliably exhibit the desired characteristics.
What is the significance of maintaining genetic diversity in selectively bred animal populations?
Maintaining genetic diversity in selectively bred animal populations is crucial for :
Resilience to disease
Good health
Adaptability of breeds over time
True or False?
Selective breeding will yield success in just a few generations.
False.
Selective breeding occurs over many generations. Although, the process is much faster than natural selection as individuals with the desired characteristics are chosen to breed at the start of the process.
Define the term genetic engineering.
Genetic engineering is a process which involves modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic.
What are the main steps in the process of genetic engineering? (Higher Tier Only)
The main steps in genetic engineering are:
Enzymes are used to isolate the required gene
This gene is inserted into a vector, usually a bacterial plasmid or a virus
The vector is used to insert the gene into the required cells
Genes are transferred to the cells of animals, plants or microorganisms at an early stage in their development so that they develop with the desired characteristics
Why are plants crops genetically engineered?
Plant crops have been genetically engineered for several reasons, including to increase resistance to diseases or to produce bigger better fruits and vegetables.
Give an example of the use of bacteria in genetic engineering.
Bacterial cells have been genetically engineered to produce useful substances such as human insulin to treat diabetes.
What are the potential benefits of genetic engineering in agriculture and medicine?
The potential benefits of genetic engineering in agriculture and in medicine are:
plants can be resistant to diseases
GM crops generally show increased yields
reduced use of pesticides and herbicides
producing useful substances such as human insulin to treat diabetes
overcoming some inherited disorders
What are the potential risks of genetic engineering in agriculture and medicine?
The potential risks of genetic engineering in agriculture and medicine are:
the effect on populations of wildflowers and insects which may be reduced/reduced biodiversity
herbicide-resistant GM crops are only effective on one type of herbicide, so there is increased dependency on this herbicide
What are genetically modified (GM) crops?
Crops that have had their genes modified by introducing a gene from another organism are called genetically modified (GM) crops.
Define tissue culture.
Tissue culture is using small groups of cells from part of a plant which is used to grow identical new plants.
Why is tissue culture important?
Tissue culture is important to preserve rare plant species or for commercial benefit in nurseries.
Define the term cutting in the context of plant cloning.
A cutting is a method used by gardeners to produce many identical new plants from a parent plant. Part of a plant off is cut and used to grow a new genetically identical plant.
Define embryo transplant.
Embryo transplant is splitting apart cells from a developing animal embryo before they become specialised, then transplanting the identical embryos into host mothers.
What are the steps of adult cell cloning?
The steps of adult cell cloning are:
The nucleus is removed from an unfertilised egg cell
The nucleus from an adult body cell is inserted into the egg cell
An electric shock stimulates the egg cell to divide to form an embryo
The embryo cells contain the same genetic information as the adult body cell
When the embryo has developed into a ball of cells, it is inserted into the uterus of an adult female to develop