Chapter 17
Evoution of Life
The Origin of Life
Did Life on Earth Originate on Mars?
Early Life on Earth
Charles Darwin and The Origin of Species
How Natural Selection Works
Adaptation
Staying Warm and Keeping Cool
Evolution and Genetics
How Species Form
Evidence of Evolution
Fossils: Earth's Tangible Evidence of Evolution
The Evolution of Humans
History of Science: The Peppered Moth
Science and Society: Antibiotic-Resistant Bacteria
Cause of Diversity
Evolution
Lamarck’s Theory of Evolution
Darwin’s Theory of Evolution
Natural Selection
Evidence of Evolution
Misconceptions
References
Chapter 17
Evoution of Life
The Origin of Life
Did Life on Earth Originate on Mars?
Early Life on Earth
Charles Darwin and The Origin of Species
How Natural Selection Works
Adaptation
Staying Warm and Keeping Cool
Evolution and Genetics
How Species Form
Evidence of Evolution
Fossils: Earth's Tangible Evidence of Evolution
The Evolution of Humans
History of Science: The Peppered Moth
Science and Society: Antibiotic-Resistant Bacteria
Cause of Diversity
Evolution
Lamarck’s Theory of Evolution
Darwin’s Theory of Evolution
Natural Selection
Evidence of Evolution
Misconceptions
References
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
2. Evolution
• The processes that have transformed life on
earth from it’s earliest forms to the vast
diversity that characterizes it today.
• A change in the genes!!!!!!!!
3. Old Theories of Evolution
• Jean Baptiste Lamarck (early 1800’s) proposed:
“The inheritance of acquired characteristics”
• He proposed that by using or not using its body
parts, an individual tends to develop certain
characteristics, which it passes on to its
offspring.
4. “The Inheritance of Acquired
Characteristics”
• Example:
A giraffe acquired its long neck because its
ancestor stretched higher and higher into the
trees to reach leaves, and that the animal’s
increasingly lengthened neck was passed on
to its offspring.
5. Charles Darwin
• Influenced by Charles Lyell who published
“Principles of Geology”.
• This publication led Darwin to realize that
natural forces gradually change Earth’s
surface and that the forces of the past are still
operating in modern times.
6. Charles Darwin
• Darwin set sail on the H.M.S. Beagle (1831-1836)
to survey the south seas (mainly South America
and the Galapagos Islands) to collect plants and
animals.
• On the Galapagos Islands, Darwin observed
species that lived no where else in the world.
• These observations led Darwin to write a book.
7. Charles Darwin
• Wrote in 1859: “On the Origin of Species
by Means of Natural Selection”
• Two main points:
1. Species were not created in their present
form, but evolved from ancestral species.
2. Proposed a mechanism for evolution:
NATURAL SELECTION
8. Natural Selection
• Individuals with favorable traits are more
likely to leave more offspring better suited for
their environment.
• Also known as “Differential Reproduction”
• Example:
English peppered moth (Biston betularia)
- light and dark phases
9. Artificial Selection
• The selective breeding of domesticated
plants and animals by man.
• Question:
What’s the ancestor of the domesticated dog?
• Answer: WOLF
10. Evidence of Evolution
1. Biogeography:
Geographical distribution of species.
2. Fossil Record:
Fossils and the order in which they appear
in layers of sedimentary rock (strongest
evidence).
12. Evidence of Evolution
3. Taxonomy:
Classification of life forms.
4. Homologous structures:
Structures that are similar because of
common ancestry (comparative anatomy)
13. Evidence of Evolution
5. Comparative embryology:
Study of structures that appear during
embryonic development.
6. Molecular biology:
DNA and proteins (amino acids)
14. Population Genetics
• The science of genetic change in
population.
• Remember: Hardy-Weinberg equation.
16. Species
• A group of populations whose individuals
have the potential to interbreed and produce
viable offspring.
17. Gene Pool
• The total collection of genes in a
population at any one time.
18. Hardy-Weinberg Principle
• The concept that the shuffling of genes that
occur during sexual reproduction, by itself,
cannot change the overall genetic makeup
of a population.
19. Hardy-Weinberg Principle
• This principle will be maintained in nature
only if all five of the following conditions are
met:
1. Very large population
2. Isolation from other populations
3. No net mutations
4. Random mating
5. No natural selection
22. Microevolution
• A change in a population’s gene pool
over a secession of generations.
• Evolutionary changes in species over
relatively brief periods of geological time.
23. Five Mechanisms of Microevolution
1. Genetic drift:
Change in the gene pool of a small
population due to chance.
• Two examples:
a. Bottleneck effect
b. Founder effect
24. a. Bottleneck Effect
• Genetic drift (reduction of alleles in a population)
resulting from a disaster that drastically reduces
population size.
• Examples:
1. Earthquakes
2. Volcano’s
25. b. Founder Effect
• Genetic drift resulting from the colonization
of a new location by a small number of
individuals.
• Results in random change of the gene pool.
• Example:
1. Islands (first Darwin finch)
26. Five Mechanisms of Microevolution
2. Gene Flow:
The gain or loss of alleles from a
population by the movement of individuals
or gametes.
• Immigration or emigration.
27. Five Mechanisms of Microevolution
3. Mutation:
Change in an organism’s DNA that
creates a new allele.
4. Non-random mating:
The selection of mates other than
by chance.
5. Natural selection:
Differential reproduction.
28. Modes of Action
• Natural selection has three modes of action:
1. Stabilizing selection
2. Directional selection
3. Diversifying selection
Number
of
Individuals
Size of individuals
Small Large
29. 1. Stabilizing Selection
• Acts upon extremes and favors the
intermediate.
Number
of
Individuals
Size of individuals
Small Large
30. 2. Directional Selection
• Favors variants of one extreme.
Number
of
Individuals
Size of individuals
Small Large
31. 3. Diversifying Selection
• Favors variants of opposite extremes.
Number
of
Individuals
Size of individuals
Small Large
33. Reproductive Barriers
• Any mechanism that impedes two species
from producing fertile and/or viable hybrid
offspring.
• Two barriers:
1. Pre-zygotic barriers
2. Post-zygotic barriers
34. 1. Pre-zygotic Barriers
a. Temporal isolation:
Breeding occurs at different times for
different species.
b. Habitat isolation:
Species breed in different habitats.
c. Behavioral isolation:
Little or no sexual attraction between
species.
35. 1. Pre-zygotic Barriers
d. Mechanical isolation:
Structural differences prevent gamete
exchange.
e. Gametic isolation:
Gametes die before uniting with gametes
of other species, or gametes fail to unite.
36. 2. Post-zygotic Barriers
a. Hybrid inviability:
Hybrid zygotes fail to develop or fail to
reach sexual maturity.
b. Hybrid sterility:
Hybrid fails to produce functional gametes.
c. Hybrid breakdown:
Offspring of hybrids are weak or infertile.
37. Allopatric Speciation
• Induced when the ancestral population
becomes separated by a geographical
barrier.
• Example:
Grand Canyon and ground squirrels
38. Adaptive Radiation
• Emergence of numerous species from a
common ancestor introduced to new and
diverse environments.
• Example:
Darwin’s Finches
39. Sympatric Speciation
• Result of a radical change in the genome that
produces a reproductively isolated sub-
population within the parent population (rare).
• Example: Plant evolution - polyploid
A species doubles it’s chromosome # to
become tetraploid.
reproductive
sub-population
Parent population
40. Interpretations of Speciation
• Two theories:
1. Gradualist Model (Neo-Darwinian):
Slow changes in species overtime.
2. Punctuated Equilibrium:
Evolution occurs in spurts of relatively
rapid change.
41. Convergent Evolution
• Species from different evolutionary branches
may come to resemble one another if they live in
very similar environments.
• Example:
1. Ostrich (Africa) and Emu (Australia).
2. Sidewinder (Mojave Desert) and
Horned Viper (Middle East Desert)
42. Coevolution
• Evolutionary change, in which one species
act as a selective force on a second
species, inducing adaptations that in turn act
as selective force on the first species.
• Example:
1. Acacia ants and acacia trees
2. Humming birds and plants with flowers
with long tubes