bio natural selection

What is natural selection?

The process where organisms with characteristics best suited to their environment are more likely to survive and reproduce, passing on their advantageous traits to the next generation.

What are the main steps of evolution by natural selection?

1. Variation exists within a population due to genetic mutations. 2. Organisms with advantageous characteristics are more likely to survive and breed. 3. Beneficial traits are passed to the next generation. 4. Over generations, allele frequencies for advantageous traits increase.

Who were the key scientists involved in developing the theory of evolution by natural selection?

Charles Darwin and Alfred Russel Wallace.

What types of evidence support the theory of evolution?

Fossil evidence, dating of stone tools, anatomical evidence (such as the pentadactyl limb), and emerging resistance in bacteria.

Explain the process of speciation.

1. Variation exists due to mutations. 2. Alleles with survival advantages are selected. 3. Populations become isolated. 4. Different advantageous alleles are selected. 5. Genetic variation increases over time. 6. New species form when populations can no longer breed.

What is selective breeding?

A process where humans choose which organisms to breed to produce offspring with desired characteristics.

What is genetic engineering?

Modifying an organism's genome by introducing a gene from another organism to achieve a desired characteristic.

Give examples of the applications of genetic engineering.

Creating disease-resistant crops, producing larger fruits, engineering bacteria to produce human insulin, developing Bt crops, and potential gene therapy for inherited disorders.

What are some concerns associated with genetic engineering?

Potential negative effects on biodiversity, gene spread to wild plants, uncertainties about human health effects, and ethical concerns regarding 'designer babies'.

Explain the development of antibiotic resistance in bacteria.

Mutations lead to antibiotic resistance; exposure to antibiotics creates selection pressure; resistant bacteria survive and reproduce, increasing resistance gene frequency.

What are the Five Kingdoms and Three Domains systems of classification?

Five Kingdoms: Animals, Plants, Fungi, Prokaryotes, Protists. Three Domains: Archaea, Bacteria, Eukaryota, based on genetic analysis.

What is a pentadactyl limb?

A limb with five digits found in various animals, suggesting a common ancestor and adaptations due to different selection pressures.

What was Alfred Russel Wallace's contribution to the theory of evolution?

Developed the theory of speciation and the concept of evolution by natural selection, recognized that those lacking advantageous traits would die out.

Why was there controversy surrounding Darwin's theory of evolution?

It contradicted religious beliefs and there was limited understanding of inheritance during his time.

What is significant about the fossil 'Ardi'?

Ardi is the oldest known human ancestor, exhibiting both humanoid and ape-like traits, supporting gradual evolution.

What is significant about the fossil 'Lucy'?

Lucy walked upright with a human-like posture and a chimp-like skull, representing an intermediate stage between apes and early humans.

What did Louis and Mary Leakey discover that supported the theory of natural selection?

Fossils indicating early toolmakers and Homo habilis, an important early human species.

How can we date stone tools?

Using radiometric carbon dating of associated once-living materials or stratifying rock layers.

What are the problems associated with selective breeding?

Can lead to inbreeding, a reduced gene pool, increased vulnerability to diseases, and genetic defects.

What are the benefits and risks of tissue culture in plants?

Benefits: Produces many offspring with desirable features. Risks: Reduces gene pool and may have a low survival rate.

What role do restriction enzymes and ligase play in genetic engineering?

Restriction enzymes cut out desired genes and open the vector, while ligase joins them together to form recombinant DNA.

What are some advantages of genetically modified (GM) crops?

Increased resistance to insects and herbicides, improved nutritional content, and adaptability to different conditions.

What are some disadvantages of genetically modified (GM) crops?

Potential negative impacts on biodiversity, gene spread causing infertility, and unknown health effects on humans.

How does antibiotic resistance in bacteria support Darwin's theory of natural selection?

Resistance emergence shows natural selection in action, as antibiotics create selection pressure leading to the survival and reproduction of resistant bacteria.

What is the difference between the Five Kingdoms and Three Domains systems of classification?

Five Kingdoms classifies based on visible traits, while Three Domains classifies based on genetic analysis.

Why is the pentadactyl limb considered evidence for evolution?

It suggests a common ancestor shared by diverse species that adapted the basic limb structure for different functions.