Evolution and the Origin of Life

Evolution

• Evolution is the process of change in living organisms over time, from generation to generation.

Origin of Life

• Aristotle, a Greek philosopher, proposed that termites originated from decaying wood and worms originated from soil.
• The theory of Abiogenesis/Generatio Spontanea, supported by Aristotle, suggests that living things arise from non-living matter spontaneously.
• Antonie van Leeuwenhoek supported Abiogenesis, stating that microorganisms come from water.
• In the 17th century, he observed microorganisms in rainwater and hay infusions using a microscope.
• Needham believed microorganisms arose from broth.
• His experiment involved boiling meat, then storing the broth in an open container, which became cloudy with microorganisms after a few days.

Biogenesis Theory

• This theory states that living things come from pre-existing living things, a conclusion drawn from experiments.
• Francesco Redi (1668), an Italian scientist, conducted experiments to prove that maggots do not appear spontaneously on decaying meat.
• Redi's experiment involved three jars containing raw meat, one left open, one tightly sealed, and one covered with gauze.
• Lazzaro Spallanzani (1765) tested spontaneous generation of microorganisms in boiled broth.
• He boiled broth in two glass bottles, leaving one open and sealing the other after boiling.
• The open bottle became filled with microorganisms, while the sealed bottle remained sterile.
• Louis Pasteur boiled broth in a flask and sealed it with an S-shaped tube, keeping the flask open to air.
• The broth remained clear and sterile, leading to the idea that "Omne Vivum ex Ovo" and "Omne Ovum ex Vivo" which means life comes from eggs, and eggs come from living things.

Chemical Evolution Theory

• Chemical evolution suggests life originated from reactions between CH4, NH3, H2, and H2O in the atmosphere with cosmic rays and lightning.
• Harold Urey proposed that life began with inorganic compounds in the atmosphere like methane (CH4), hydrogen (H2), water vapor (H2O), and ammonia (NH3).
• Atmospheric compounds, reacted with cosmic energy and electrical discharges, formed amino acids.
• Stanley Miller's experiment proved Urey's theory using a device known as the primitive atmosphere apparatus to create amino acids from inorganic compounds.
• Complex compounds such as lipids, sugars, amino acids, and nucleotides, can form under abiotic conditions.

Stages of Chemical Evolution

• Simple organic compounds form from gases using lightning energy.
• More complex compounds, like amino acids and nucleotides, develop.
• Simple molecules and polymer molecules create cellular aggregates.
• Nucleotides undergo polymerization, forming RNA.
• RNA acts as a carrier of genetic information.
• Aggregate chemical reactions become trapped in hydrophobic barriers.

Stanley Miller Experiment

• The Stanley Miller experiment's results proved that gases can form amino acids.
• Amino acids are the smallest molecules that make up proteins and are essential organic compounds, which make them foundational to life.

Biological Evolution

• Amino acids from atmospheric reactions fall to earth with rain.
• Life originated from the oceans.
• Only specific depressions in the ocean are likely places for life to thrive.
• These depressions have less water due to evaporation, and are rich in organic compounds, forming the "primordial soup."

Origin of living things.

• A sequence exists from inorganic molecules, organic monomers, organic polymers (protenoids), protobionts (primitive cells), to primitive prokaryotic cells.

Emergence of Eukaryotic Life

• Prokaryotes, anaerobic and heterotrophic, are surrounded by a plasma membrane and contain DNA (1).
• Aerobic prokaryotes use mitochondria (2).
• Invagination of the plasma membrane occurs (3).
• Proeukaryotic cells develop (4).
• Protista, fungi, and animal cells emerge, along with algae and plant cells containing chloroplasts and other organelles (5).

Microevolution

• Evolution occurs at the gene level.
• Changes in genes lead to genotypic variations.
• Genotypic variations prove microevolution.
• Microevolution does not lead to new species (macroevolution).
• Changes in genes do not necessarily lead to new species.

Darwin vs. Lamarck

• Lamarck's theory suggests that giraffes originally had short necks, but constantly stretching to reach food led to elongated necks over generations.
• Darwin's theory states that giraffe populations have different neck lengths, and those with longer necks are more likely to survive and reproduce.

Lamarack's Theory of Evolution

• According to Lamarck, all giraffes initially had short necks and high treetop food was hard to reach.
• Reaching for leaves increased neck length, passing elongations to future generations.
• Adaptations were inherited, leading to the long necks of modern giraffes.

Darwin's Theory of Evolution

• There is variations between living things.
• Living things require sufficient food and space to survive.
• Living thing populations increase geometrically, while the food supply increases arithmetically.
• Living things compete to survive.
• Living things adapt to their environments.
• Not all living things survive; some die.
• Darwin's theory of evolution is known for natural selection.

Darwin's Theory of Evolution: Giraffes

• Giraffe populations vary, with some having long necks and others short.
• Natural selection favored giraffes who were able to reach food, leading to the demise of the short-necked giraffes.
• This survival of the fittest resulted in the current generation of long-necked giraffes.

Factors Related to Evolution

• Population
• Heredity/inheritance of traits
• Environment
• Ability to adapt

Definition of Evolution

• Evolution the process of change in organisms slowly, from one generation to the next, requiring long periods.

Types of Evolution

• By direction, there is progressive (survival) and regressive (extinction) evolution.
• By scale, there is macroevolution and microevolution.
• By outcome, there is divergent (many) and convergent (few) evolution.

Evidence of Evolution

• Fossils as evidence of the past
• Current variations in living organisms
• Homology of organs
• Comparative embryology
• Comparative biochemistry

Evidence of Evolution

• Variations found in a species can lead to the development of new species.
• Fossils found in different layers of the earth record change over time; like the development of the horse.

Fossils

• Fossils are the remains of dead organisms that have become petrified.
• Older fossils show that past life was different from current life.
• Fossils show that organisms have changed over time; there is a transformation of life.

Homology and Analogy

• Homologous organs share a similar basic structure but differ in function.
• An example of homologous structures is the wing of a bird and the arm of a human.
• The front leg of a horse and the fin of a whale are also homologous.
• Analogous organs have the same function but different original structures.
• An example of analogous is the wing of an insect and the wing of a bird.

Comparative Embryology

• Early embryos of vertebrates look alike.
• Close relationships between organisms have highly similar embryos.
• Ontogeny is the development of an individual from a single cell to an adult, while phylogeny is the evolutionary history of organisms.
• Some scientists think ontogeny summarizes phylogeny.

Comparative Biochemistry

• Comparing DNA structures among organisms shows how life came from the same ancestor.
• DNA is made of the same things (phosphates, sugars, and nitrogenous bases).

Evolutionary Vestiges

• Tail bone
• Appendix
• Pointed canine teeth
• Ear muscles
• Nictitating membrane of the eye

Mechanisms of Evolution

• Three grasshoppers feature different variations; the first has the ability to blend into its environment, while the other two are more visible.
• Variations make it easier or harder for predators to hunt.
• Evolution happens through variations within the same species.

Mutation

• Seedless watermelons are created through human modification for fruit size and taste.
• If seedless watermelons dominate, then mutations can cause evolution.

Mutation Facts

• Mutations happen randomly and not directed by the environment.
• Mutation happens in all species.
• Mutations tend to harm existing species.

Mutation and Evolution

• Mutation facilitates evolution.
• Gametes harbor thousands of genes.
• Individuals make millions of gametes per generation.
• A species turns out many generations over time.

Variation and Evolution

• Evolution happens through variation.
• Variation happens through genetic recombination during the formation of gametes.

Natural Selection

• Natural selection favors adaptive traits.
• Natural selection emphasizes reproduction and adaptation.
• Abundant reproduction makes things competitive.
• Progeny better at adapting survive, while others parish.

Selective Breeding

• Humans have bred certain species to ensure a certain trait is passed down.
• Selective breeding makes quick and fast changes.

Selective Breeding Examples

• Cabbage, kale, kohlrabi, cauliflower, broccoli, and mustard can all come from one source.

Mutation, Adaptation, and Speciation

• The flow of evolution can be observed in the sequence of mutations, genetic recombination, genetic variation, adaptation and speciation.

Hardy-Weinberg Principle

• States that genetics in a population stay constant from generation to generation.
• All genotypes have the same ability to survive and reproduce.
• Genotypes randomly mate.
• There are no mutations in genes.
• The population must be fairly large.
• Migration cannot happen.
• There is no natural selection.

Formulas of the Hardy-Weinberg Principle

• p + q = 1 or 100%
• (p + q)2 = 1 or 100%
• p2 + 2pq + q2 = 1 or 100%
  • where:
    • pp = homozygous allele
    • pq = heterozygous allele
    • qq = recessive homozygous allele

Example Question

• One out of 10,000 people have albinism. What are the frequencies of the normal and albino alleles, as well as their genotypes, and how many of people are normally heterozygous? Jawab : p = normal q = albino p2 + 2pq + q2 = 10.000 q2 = 1 orang a. Frekuensi q2 = 1 = 0,0001 10.000 q =√0,0001 = 0,01 p +q = 1 p = 1 − 0,01 = 0,99 b. Frekuensi genotip = p2: pq: q2 = 0,9801 : 0,0198 : 0,0001 = 9801:198:1 c. Orang normal heterozigot bergenotip 2pq = 2(0,99 X 0,01) = 0,0198 X 10.000 = 198 Jadi orang yang normal heterozigot 198 orang

Gene Frequency Change

• Gene frequency changes may happen through mutation, natural selection, migration, changes in the environment, recombination, and selection.

Speciation

• Speciation is the evolutionary process by which new biological species arise.
• Factors include geographic and reproductive isolation.