Origin of life: Creationism, Panspermia, Abiogenesis

• The origin of life is a topic with more questions than answers, studied across various fields of knowledge.

Origin of Living Beings

• How life began on Earth
• Scientists, religious figures, and philosophers have tried to answer this for a long time

Creationism and Fixism

• Creationism explains the emergence of living beings through divine creation
• It posits that living beings were created individually by one or more divinities
• Fixism is the idea that living beings have not changed over time

Panspermia and Extraterrestrial Origin

• The theory of panspermia, proposed by Arrhenius, suggests that life originated elsewhere in the Universe
• Organisms were brought to Earth via spores or resistant forms attached to meteorites
• They survived harsh conditions in space, colonized Earth, and evolved

Spontaneous Generation or Abiogenesis

• Abiogenesis suggests that living beings arise spontaneously from non-living matter
• Heat, humidity, sunlight, and even stars were believed to stimulate the generation of life

Biogenesis

• The theory of biogenesis states that living beings originate only from pre-existing living beings
• Francesco Redi conducted experiments in 1668 that involved investigating the origin of worms
• Redi observed that flies are attracted to decaying matter, lay eggs on it, and larvae emerge from these eggs

Biogenesis vs. Abiogenesis

• Anton van Leeuwenhoek's discovery of microorganisms through microscopes revived the debate
• Abiogenesis supporters argued that microorganisms could arise from non-living matter

Pasteur and the Proof of Biogenesis

• Louis Pasteur conducted experiments in the 1860s, that proved microorganisms arise from pre-existing ones
• Pasteur placed a nutrient-rich liquid in glass flasks with long, swan-shaped necks
• The necks were curved through heating and created filters, preventing contamination
• After boiling and cooling, condensation occurred in the neck tube that trapped particles from the air
• Some flasks were left intact and the liquid remained sterile. Others had their swan necks broken
• In the flasks with broken necks, the liquid became cloudy and contained microorganisms
• Intact flasks remained transparent and sterile
• Pasteur's experiment explained that the presence of microorganisms in flasks occurred because of air

How Did the First Living Being Arise?

• The experiments of Pasteur only resolved a small part of the problem
• Haldane in London an Oparin in Russia created the book The Origin of Life
• These proposed to explain the new dilemma for science of how did the first living being arise

Oparin's Theory

• Carbon atoms combined to form organic molecules
• Oparin states that protoplasm formation requires chemical elements present in the primitive atmosphere
• Constant rain led to the formation of the first seas with proteins
• The molecules joined, split, and recombined forming small coacervates

Miller and Fox Experiments

• Stanley Miller confirmed Oparin's hypothesis in 1953
• Miller built an apparatus simulating primitive Earth conditions
• Methane and ammonia circulated under electrical discharges
• After 24 hours, methane carbon converted into amino acids and other organic molecules
• The Miller experiment demonstrated the possibility of forming organic molecules in the primitive atmosphere

General Characteristics of Living Beings

• Living beings exhibit properties like reproduction, genetic variability, and heredity
• Also evolve

Chemical Composition

• Carbon is fundamental for organic substances
• Substances include proteins, carbohydrates, lipids, and nucleic acids, water, and mineral salts

Cellular Organization

• The cell is the morphological and functional unit of living beings
• Organisms can be unicellular or multicellular
• Cell types: prokaryotic and eukaryotic

Endosymbiotic Hypothesis

• Lynn Margulis proposed the endosymbiotic hypothesis
• Organelles in eukaryotic cells, like chloroplasts and mitochondria, originated from symbiotic associations between organisms
• Chloroplasts and mitochondria would have originated from autotrophic prokaryotes

Genetic Information

• Genetic information is contained in genetic material
• DNA comprises a long linear chain of nucleotides

Metabolism

• Metabolism is the set of chemical reactions that occur in the body and involves the transformation and utilization of matter and energy

Reproduction and Development

• Reproduction is an essential process for descendents
• Organisms reproduce in a way that can be sexual, through sex cells, or asexual, through the corporeal division

Environmental Interaction

• Organisms interact with their environments
• Ecology studies this interaction
• Irritability is the responsiveness of living beings to environmental stimuli

Fixist Theory and Evolutionary Ideas

• The fixist theory asserts that living beings and their characteristics do not change over time

Evolutionary Ideas

• The naturalists Darwin and Wallace defend that organisms change over time and that this change is selected by the environment
• Individuals promoting better adaptation to the environment have chances for survival, transmitting to descendants advantageous characters

Evidences of Evolution

• Series of evidences corroborates the evolution theory, fossils, homology, embryology, and comparated anatomy, vestigial organs and molecular data

Fossils

• Paleontology studies fossils
• Fossils are remains or vestiges of the beings that lived in past times, conserved in layers of rocks

Homology

• homologous structures derive from already existing structures in a common ancestral
• Organs with the same embryonic origin can have different functions and be homologous

Analogous Structures

• Analogous structures are those that perform the same function, but do not derive from modifications of similar original structures
• Organs of the same function, but with different structures and embryonic origins

Comparated Embriology

• There are evidences that can be found in the embryonic development, specially of the animals

Comparated Anatomy

• The body of plants and the animals present characters that relate with their kinship
• They have the same disposal of bones, muscles, blood vessels

Vestigial organs

• Organs are reduced in size and generally not functioning with the specific living beings, they correspond to larger and functional organs in other organisms
• Presence of vestigial organs indicates common ancestry

Molecular Data

• Rate of kinship between the species can be evidenced by the comparison between molecules of DNA, RNA and of proteins
• Similarities between the sequences of nucleotides indicates that the species are more related

Lamarck's Theory or Lamarckism

• Lamarck said that the living beings had an interior impulse capable of permitting their adaptation to the environment, since they were pressed by some necessity imposed by the environment
• He said that what isn't used is atrophied and reduced and those that are being used get stronger

Use and disuse Law

• The use and disuse law propose that the use of one certain organ conducts your development and that what you don't use is atrophy
• The modifications by environmental impositions would be transmitted to the descendant by the transmission law of acquired characters

Transmission Law of Acquired Characters

• Is the concept that the modifications acquired by the organism in the adptation on life, in automatical form, aren't transmissible

The Criticisms on Lamarckism

• The "Perfection Search" , and your necessity of adaptation can't be proven

Darwin's Theory

• Darwin said that every organism descend from common ancestors
• He also proposed that the environment selected the individuals

Natural Selection

• The Organisms that are more adapted to that environment have bigger chances of survival
• Darwin sais that natural is related with what already it's related with the individuals, that are intimately related
• The individuals have and exclusive combination of traces, like size, color, resistance to the cold, heat etc

Types of Natural Selection

• Directional Selection: In situations where just one of the extremes has an advantages
• Normalization Selection: That occurs when the ambient favors the individuals of intermediate sizes
• Disruptive Selection: That occurs when the extremes are the lavored ones

Sintetic Theory of the Evolution

• Was when the genetics theory started to make more sense
• The genetic variability the species depends on what factor as the genre flow in the species, transmission of horizontal genres

Evolutionary Factors

• Mutational and Chromosomal
• Genetic recombination
• Natural Selection: The most adapted individuals to the environment is better
• Isolation reproductive

Reproductive Isolation

• Consists in the incapacity, or partial, or parts of different species to cross

Migration

• Process of the entrance or exit, if those individuals of the population
• If the group it's big, may the effect for a genetic origin

Genetic derives

• When their it's a change, in a genetic frequency, from a small Population, it's given the name of derive, or genetic oscillation
• The genetic derive it can be one: effect founder, effect neck of the Carafle

The Beginnings

• In that case it's responsible for studying life in their different levels
• The Bioquinica examines the atomics relationship
• The Ecology it's the science responsible for Studying the relations between organism

Levels of Organization

• The Population, The Community, The Ecosystem, and the Biosphere
• Population: A population if defined for the combination of organ in the same especific, that habit a determinate local

Community

• A combination of species who habit that local at that time period

Ecosystem

• an ecosystem it's that limited part of a determined region that include all the organism

Biosphere

• A biosphere comprise all the planets region

Dynamic of population

• in that ecosystem one the population is more is big, more that specific place
• there's 2 importan factors to characterize a population; the population Density and the increase rate