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Pattern of evolution

The document details various evolutionary patterns, including convergent, divergent, and parallel evolution, along with coevolution and their implications on species adaptation and diversity. It explains how organisms change over time, leading to speciation and the emergence of analogous and homologous structures. Additionally, it distinguishes between macroevolution and microevolution, highlighting their roles in the broader context of biological diversity and adaptation.

Science◦
Contents Patten of Evolution  Evolution  Convergent Evolution  Analogous structures  Divergent Evolution  Homologous structures  Parallel Evolution  Coevolution  Types of Evolution • Macroevolution • Microevolution  Importance of pattern of evolution
Evolution “Evolution, or change over time, is the process by which modern organisms have descended from ancient organisms. ”  Evolution also explains how modern organisms have descended from ancient organisms.  Evolution is the Process by which organisms pass on traits from generation to generation.  Explains the origin of new species and diversity. Change over time
PATTERN OF EVOLUTION Convergent Evolution  In evolutionary biology, convergent evolution is the process whereby organisms not closely related , independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.  Animals come from different ancestral lineages  Caused by environmental changes  Also called convergence Examples i. shark and dolphin bodies, ii. vertebrate and cephalopod eyes iii. the relationship between bat and insect wings,
Analogous Structures  Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups.  Organisma have the same function but not same the structure.  Analogous structures arise from convergent evolution.
Divergent Evolution  “Divergent evolution is defined as what occurs when two groups of the same species evolve different traits within those groups in order to accommodate for differing environmental and social pressures”.  Species gradually become different from its ancestors  Evolution resulted in multiple different species, leading to speciation  Homologous structure development  Also called adaptive radiation  Caused by environmental changes, migration
Examples of Divergent Evolution • Darwin’s Finches Finches on the Galapagos islands evolved into many different species to eat different foods. • Polar bear and brown bear • Red fox and kit fox
Homologous Structue  In divergent evolution, homologous structures are structures indicating a species is diverging from its ancestor.  These structures need not have the same function as that of those of the species' ancestors.  Same structure  Different function  homologous structures arise via Divergent evolution .  Example  the forelimbs of humans and bats are homologous structures.
Parallel Evolution  Some species evolve without converging on similar traits or diverging to different traits. These species undergo change, but they maintain a constant level of similarity to each other. This process is known as parallel evolution.  Parallel evolution occurs when two species evolve independently of each other, maintaining the same level of similarity.  Parallel evolution usually occurs between unrelated species that do not occupy the same or similar niches in a given habitat
Examples  Marsupials and placental mammals most recently shared common ancestor 125- 150 million years ago.yet these similar features appeared in each of the distant relatives
Parallel Evolution
Coevolution  “The Process By Which Two Species Evolve In Response To Changes In Each Other”  Species that live in a close relationship with each other, such as a predator-prey or symbiotic relationship, often evolve adaptations to each other in a process called coevolution. Types of Coevolution i. Parasite –host coevolution ii. Mutualistic/Beneficial coevolution iii. Predatory/prey coevolution
Examples of Coevolution  Mutualistic/Beneficial coevolution I. yucca moth (Tegeticula yuccasella)A female yucca moth pushing pollen into the stigma tube of the yucca flower while visiting the flower to deposit her eggs.  Predatory-prey coevolution I. One common example is the relationship between some species of birds and butterflies.
Parasite-host coevolution  One organism lives on other organism harming it and possibly causing death.  The parasite live on or in the body of the host  Maize plant (host) and Oospores (parasite)  Cor/ Maize disease
Macroevolution  Descent with modification  The process by which modern organism have descended from ancient ancestor due to many small changes over millions years (Long time)  macroevolution describes patterns on the tree of life at a grand scale across vast time periods.  Many different patterns can be observed across the tree of life at a grand scale , including • stability • gradual change • rapid change • adaptive radiations(Divergent evolution) • extinctions • the co-evolution of two or more species • convergent evolution in traits between species
Examples of Macroevolution  The origin of eukaryotic life forms  the origin of humans  the origin of eukaryotic cells  extinction of the dinosaurs.
Microevolution  Small changes within a species’s set of genes that result in phenotypic differences  Decades or centuries (Short time)  Under certain environmental conditions,can produce new ,closely related species.  Variants in color are a form of microevolution  Microevolution describes mechanisms that alter the frequencies of alleles in gene pools within species  These mechanisms include • mutation • Migration • genetic drift • natural selection
Examples of Microevolution • Animals adjusting to camouflage is an example of microevolution.
Importance of Pattern of Evolution  Evolution also helps in promoting biodiversity.  It leads to speciation, it could lead to a wide range of different organisms thriving in diverse habitats.  Divergent evolution allows species with common ancestral origin to be able to adapt to their own habitats.
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