Unit 1 Biological Diversity

Biological Diversity

• A species is a group of organisms with similar characteristics that can interbreed and produce fertile offspring.
• Intraspecies variation refers to the differences within a species, such as different hair colors in humans.
• Interspecies variation refers to the differences between species, such as dogs having four legs and chickens having two legs.

Adaptations

• An adaptation is a characteristic that helps an organism survive in its environment.
• Structural adaptations include physical features such as wings, webbed feet, and elephant tusks.
• Behavioural adaptations include hibernation, migration, and nocturnal behaviour.

Speciation and Evolution

• Speciation is the formation of new and distinct species through evolution.
• Competition between species can lead to speciation.
• Charles Darwin's theory of natural selection states that favourable traits become more common in successive generations, while unfavourable traits become less common.
• Common ancestors can give rise to new species through speciation.

Niche

• A broad niche refers to an organism's ability to tolerate a variety of environmental conditions and eat a wide range of foods, such as raccoons.
• A narrow niche refers to an organism's limited tolerance for specific environmental conditions and diet, such as pandas.

Reproduction

• Sexual reproduction promotes biodiversity by producing genetically unique offspring, increasing variation within a population.
• Asexual reproduction lacks genetic variation, making offspring more vulnerable to disease.
• Types of asexual reproduction include binary fission, asexual spores, budding, and vegetative reproduction.

Inheritance

• Heritable traits are passed on from parents through sexual reproduction, such as eye colour.
• Non-heritable traits are acquired by the individual during their lifetime, such as a tattoo.
• Continuous variation results in a wide range of possible phenotypes, such as eye colour.
• Discrete variation results in only a few possible phenotypes, such as blood type or earlobe shape.

DNA and Chromosomes

• A base is one of the building blocks of DNA, including cytosine, guanine, adenine, and thymine.
• A nucleotide includes one nitrogen base, one sugar, and one phosphate.
• A chromosome is a section of DNA containing several genes.
• DNA includes all the chromosomes, which are stored in the nucleus of a cell.
• A cell is the smallest unit of life, containing all the genetic information.

Mutations and Cell Division

• A mutation is a change or variation in the structure of a gene.
• A mutagen is a substance or form of energy that causes a mutation.
• Mitosis is a type of cell division used for growth and repair.
• Meiosis is a type of cell division that results in the production of sperm and egg cells.