IB BIOLOGY Topic 5: Evolution and Biodiversity

Evolution

The gradual and cumulative change in the heritable characteristics of a population over many generations.

Fossil Records

Preserved remains of organisms from the past that show the gradual changes in species over time.

Selective Breeding

The process of humans selectively breeding plants and animals to enhance specific genetic traits.

Homologous Structures

Common internal structures that appear in seemingly dissimilar animals due to shared ancestry.

Vestigial Structures

Remnants of structures that no longer serve a purpose in modern organisms.

Comparative DNA Analysis

Comparing the DNA of different species to identify genetic similarities and differences.

Observable Change

The observation of species adapting to their environment or exhibiting changes over time.

Gradual Divergence

Genetic variation within populations leading to speciation when two populations become geographically separated.

Natural Selection

The process by which individuals with better adaptations are more likely to survive and reproduce.

Variation

Genetic variation among individuals within a species is necessary for natural selection to occur.

Adaptations

Characteristics that enhance an individual's suitability to its environment and way of life.

Overproduction

Species tend to produce more offspring than their environment can support.

Survival of the Fittest

Individuals with better adaptations are more likely to survive and reproduce.

Reproduction

Passing on characteristics to offspring through reproduction.

Occurrences of Natural Selection

Natural selection operates when there is genetic variation within a species.

Genetic Variation

Variation arises from mutations, meiosis, and sexual reproduction.

Struggle for Survival

Competition for limited resources leads to the survival of individuals with advantageous traits.

Antibiotic Resistance

Genetic changes in bacteria can lead to resistance against antibiotics.

Beak Changes in Finches

The shape of finch beaks changes in response to environmental food availability, illustrating natural selection.

Binomial Nomenclature

The system of naming species with a unique scientific name consisting of genus and species.

Taxonomy

The hierarchical classification system used to categorize organisms into different taxa.

Identification of Species

Organizing species into similar groups based on shared characteristics.

Dichotomous Key

A tool used to identify organisms based on observable characteristics.

Plantae Classification

Classification of plants into different groups based on characteristics like vascular tissue and reproductive methods.

Animalia Classification

Classification of animals into different groups based on characteristics like symmetry and presence of mouth and anus.

Cladograms

Tree diagrams illustrating the evolutionary relationships among species.

Clades

Groups of organisms that share a common ancestor.

Time Correlation

Genetic differences accumulate over time, allowing estimation of divergence times.

Analogous Structures

Superficially similar structures in different groups due to similar functions and habitats.

Homologous Structures

Similar structures in different organisms resulting from common ancestry.

Reclassification

Cladistics has prompted reclassification of species or groups based on molecular evidence.