IB Biology Topic 4 Cram sheets

Explore the role of base sequences, selective breeding, reproductive isolation, speciation, homologous and analogous structures in changing a population’s heritable characteristics.

Explore the factors affecting speciation, including reproductive isolation, hybridization, sterility, and polyploidy.

Discover the variety of life, considering how extinction, ecosystem loss, and biodiversity crisis influence this. Explore the differences between past and present species on Earth, understanding the need for conservation programmes.

Explore habitats, considering how limiting factors and abiotic environment adaptation affects species distribution. Understand how this relates to the characteristics of terrestrial biomes, including coral reefs, deserts, and tropical rainforests.

Discover the role of a species in an ecosystem. Explore oxygen and nutrition adaptations amongst species, considering how these contribute to fundamental niches.

Explore the interaction between species, considering the role of resource availability, competition, negative feedback, and mutualism in influencing this. Discover the use of tools, including chi-squared tests and population curves, in representing this relationship.

Discover energy transfer in ecosystems, considering the role of organic and inorganic material in enabling this. Explore the use of food chains, energy pyramids, and carbon-cycle diagrams in representing energy flow and its limitations. 

Explore the drive for evolutionary change, understanding the role of sexual reproduction, mutations, and natural selections in selecting population characteristics.

Discover gene pools, the combined characteristics of populations. Consider the role of allele and genotype frequency, as well as genetic equilibrium and trait selection in influencing this.

Discover the properties of natural ecosystems, considering the conditions required to maintain this stability. Understand the importance of sustainability and the consequences of ecosystem stability disruption.

Explore the features of ecological succession, considering how this process differs based on environmental and community changes.

Explore the causes and mechanism of climate change, considering the consequences of this on species, habitats, and ecosystems. Discover methods for carbon sequestration as a means of tackling climate change.

Discover phenology, the timing of biological events. Consider the role of climate change in disrupting phenology and evolution.