B6: Life on earth - past, present and future

How was the theory of evolution developed?

The theory of evolution was developed through observations of variation, inheritance, and natural selection, with contributions from scientists like Charles Darwin, Alfred Russel Wallace, and Jean-Baptiste Lamarck.

How does evolution of a species occur?

Evolution occurs through random DNA mutations, some of which are advantageous. These mutations increase survival and reproductive success, are passed to offspring, and increase in frequency over generations via natural selection. Over time, multiple mutations can lead to a new species.

What is selective breeding and speciation?

Selective breeding is humans breeding plants or animals for desirable traits. Speciation occurs when populations become reproductively isolated and evolve differently, forming new species.

What is evidence for evolution?

Evidence includes fossils showing gradual complexity changes, selective breeding producing new varieties, differences in isolated populations (e.g., Galapagos tortoises), and similar anatomy (e.g., pentadactyl limb).

What are modern examples of evolution?

Examples include antibiotic resistance in bacteria and DNA comparison showing genetic similarities between species.

What are differing views on evolution?

Some people reject evolution due to religious beliefs or lack of understanding, but new evidence continues to support natural selection and evolution.

How does asexual reproduction affect evolution?

Asexual reproduction produces clones with no genetic diversity. Advantages: only one parent needed, rapid reproduction, less energy. Disadvantages: lack of diversity, prone to extinction, cannot adapt, overpopulation risk.

How does sexual reproduction affect evolution?

Sexual reproduction requires two parents, producing genetically unique offspring. Advantages: genetic diversity, promotes survival, allows adaptation via natural selection. Disadvantages: requires two parents, fewer offspring, more energy.

How does biology help classify organisms?

Taxonomy classifies organisms into a hierarchy: Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species. Modern classification uses DNA and genome sequencing to reveal evolutionary relationships.

How is biodiversity threatened?

Human activities reduce biodiversity via chemicals/pesticides, habitat destruction, pollution, and introduction of invasive species (e.g., cane toads in Australia).

How can biodiversity be protected?

Through nature reserves, sustainable farming, fishing and logging management, and international treaties like the Kyoto Protocol.

What is human food security?

Food security is sustainable and accessible food supply. Threats include increasing population, changing diets, new pests/pathogens, and environmental change.

How can food security be maintained?

Conserving biodiversity, sustainable farming practices, soil fertility management, GM crops/animals, selective breeding, and optimizing growing conditions (e.g., greenhouses) help maintain food security.