4.6- Inheritance, Variation, and Evolution

These flashcards cover key concepts of inheritance, variation, and evolution in GCSE Biology for exam preparation.

What leads to unique offspring during sexual reproduction?

The combination of genetic material from two parents through meiosis.

How do gene mutations affect organisms?

They can be damaging and lead to genetic disorders or death, but occasionally they can be beneficial.

What is natural selection based on?

Variation generated by mutations and sexual reproduction.

What is selective breeding?

The process by which humans breed plants and animals for specific genetic traits.

How does meiosis differ from mitosis?

Meiosis produces non-identical cells, while mitosis produces identical cells.

What are gametes in animals?

Sperm and egg cells.

What does asexual reproduction involve?

Only one parent and no fusion of gametes, resulting in genetically identical offspring.

What is a key characteristic of gametes formed by meiosis?

They are genetically different from each other.

What does fertilization do in terms of chromosome number?

It restores the normal number of chromosomes.

What are the advantages of sexual reproduction?

It produces variation, which can provide a survival advantage in changing environments.

What are the advantages of asexual reproduction?

It requires only one parent, is more efficient, faster, and can produce many identical offspring.

What characteristic is controlled by a single gene in mice?

Fur color.

Define the term 'allele'.

Different forms of a gene.

What is a dominant allele?

An allele that is expressed even if only one copy is present.

What is a recessive allele?

An allele that is expressed only if two copies are present.

What is a homozygous organism?

An organism with two identical alleles for a trait.

What is a heterozygous organism?

An organism with two different alleles for a trait.

What is a genotype?

The genetic makeup of an organism.

What is a phenotype?

The observable characteristics of an organism.

What is polydactyly caused by?

A dominant allele.

What is cystic fibrosis caused by?

A recessive allele.

What are the sex chromosomes in females?

XX.

What are the sex chromosomes in males?

XY.

Define 'variation'.

Differences in characteristics among individuals in a population.

What can cause variation?

Genetic differences, environmental conditions, or a combination of both.

What is evolution?

A change in the inherited characteristics of a population over time.

What is selective breeding?

The process where humans breed plants and animals for desired traits.

What are genetically modified (GM) crops?

Crops that have had their genes modified for desirable traits.

What does genetic engineering involve?

Modifying an organism's genome by introducing a gene from another organism.

What is the role of enzymes in genetic engineering?

Enzymes are used to isolate and transfer genes.

What is tissue culture?

Growing identical new plants from small groups of cells.

What is cloning?

Creating genetically identical individuals from a single parent.

Who proposed the theory of evolution by natural selection?

Charles Darwin.

What is speciation?

The formation of new species due to genetic differences.

What theory challenges Darwin’s theory of evolution?

Jean-Baptiste Lamarck's theory of inheritance of acquired characteristics.

What evidence supports the theory of evolution?

Fossils, genetic data, and observable characteristics passed through generations.

What is antibiotic resistance?

The ability of bacteria to survive and reproduce despite the presence of antibiotics.

What is the binomial system?

A method of naming organisms using their genus and species names.

What is the three-domain system of classification?

Organisms are divided into Archaea, Bacteria, and Eukaryota.

What characterizes the Archaea domain?

Primitive bacteria living in extreme environments.

What should be avoided to reduce antibiotic-resistant bacteria?

Inappropriate prescriptions and failing to complete antibiotic courses.

What are fossils?

Preserved remains of organisms from the past found in rocks.

What is the significance of the fossil record?

It provides evidence for evolution and shows how species have changed over time.

What happens when a species goes extinct?

There are no remaining individuals of that species alive.

What contributes to the extinction of a species?

Natural disasters, environmental changes, and human activities.

What is the role of genetic variants in phenotype?

They can influence physical traits expressed in an organism.

What does 'punnett square' represent in genetics?

A chart used to predict the genetic outcomes of a genetic cross.

Why is the understanding of the human genome important?

It aids in searching for genes linked to diseases and understanding inherited disorders.

What is the structure of DNA?

A polymer made of two strands forming a double helix.

What are the four bases in DNA?

Adenine (A), Cytosine (C), Guanine (G), and Thymine (T).

What is the role of amino acids in proteins?

They are assembled in a specific order based on the sequence of DNA bases.

What is the importance of understanding DNA structure in biology?

It explains how genetic information is stored and transferred.

What are the disadvantages of selective breeding?

It can lead to inbreeding and increase the risk of inherited disorders.