Q2 - GenBio2 🌱 Flashcards
Is the process by which different species of organisms have developed and diversified from earlier forms throughout the history of the Earth.
Evolution
Various lines of evidence support the theory of evolution, demonstrating how life on Earth has changed over time.
Evolution
Evidences of Evolution (5):
- Fossil Evidence
- Anatomical Evidence
- Geographic Distribution of Species
- Molecular Biology
- Embryology
____ are one of the most direct pieces of evidence for evolution. They provide tangible proof that organisms from the past differ significantly from those found today and illustrate a gradual progression of evolution over millions of years.
Fossils (Fossil Evidence)
By determining the age of fossils and categorizing them from various global locations, scientists can establish a timeline of when different organisms lived relative to each other.
The fossil record reveals the evolutionary history of species, including detailed evidence of the evolution of humans and horses, showing how species have adapted and evolved over time.
FOSSIL EVIDENCE
____________ provide crucial evidence for evolution, especially through the study of homologous and vestigial structures
ANATOMICAL STRUCTURES/EVIDENCE
Anatomical structures provide crucial evidence for evolution, especially through the study of ____ and ____ structures
homologous
vestigial
These are structures in different organisms that share the same basic form due to descent from a common ancestor.
Homologous Structures
For example, the bones in the limbs of humans, dogs, birds, and whales have a similar overall construction, despite differences in shape and size that evolved over time. This similarity indicates a shared evolutionary origin.
Homologous Structures
These are remnants of structures that were functional in an organism’s ancestors but have lost their original function in modern species.
Vestigial Structures
Examples include the wings of flightless birds, hind leg bones in whales, and the human appendix. ____________ serve as evidence of evolutionary change, reflecting a species’ evolutionary history.
Vestigial Structures
This occurs when unrelated species develop similar traits due to similar environmental pressures, not because of a shared ancestry.
Convergent Evolution
For instance, the arctic fox and ptarmigan both have white winter coats to blend in with snowy environments, despite not being closely related. This phenomenon demonstrates how natural selection can lead to similar adaptations in different species.
Convergent Evolution
The ____________________ supports the theory of evolution, particularly when considered alongside the movement of tectonic plates.
Geographic Distribution of Species
Geographic Distribution of Species
Species that evolved before the breakup of the supercontinent Pangaea are found across the globe, while those that evolved after its breakup are often unique to specific regions.
Global Distribution
Geographic Distribution of Species
For example, the distinct plant and animal species in Laurasia (northern continents) and Gondwana (southern continents) emerged after these landmasses separated.
Global Distribution
Geographic Distribution of Species
Australia’s long isolation, for instance, has led to the great diversification of marsupials and the absence of other mammals.
Isolation & Endemism
The abundance of endemic species—species found nowhere else—is typical of islands and isolated regions, where species evolve independently, resulting in unique evolutionary paths.
Isolation & Endemism
MOLECULAR BIOLOGY (3):
- Universal Genetic Code
- DNA Similarities
- Gene Duplication & Evolution
The universality of DNA as the genetic material, along with the near-universal genetic code and DNA replication machinery, strongly indicates a common ancestor for all life on Earth.
Universal Genetic Code
The relatedness of organisms is reflected in the similarity of their DNA sequences, which align with the patterns expected from descent with modification. Closely related species have more similar DNA, supporting their common ancestry
DNA Similarities
DNA sequences also shed light on evolutionary mechanisms, such as the evolution of new protein functions following gene duplication events. One gene copy can mutate and evolve new functions, while the other maintains its original role, facilitating evolutionary innovation.
Gene Duplication & Evolution
EMBRYOLOGY (2):
- Conserved Developmental Stages
- Vestigial Embryonic Structures
Early embryonic development tends to be conserved across different species, reflecting their shared evolutionary history. For example, all vertebrate embryos, including humans, exhibit gill slits and tails during early development. These features disappear in adult terrestrial species but are retained in adult aquatic species, such as fish and some amphibians.
Conserved Developmental Stages
Some structures appear during embryonic development but disappear before the organism reaches adulthood. For instance, great ape embryos, including humans, develop a tail structure that is lost by birth. These vestigial embryonic structures provide insight into the evolutionary past of species.
Vestigial Embryonic Structures
Conclusion: Evidence for Evolution
The evidence for evolution is extensive and diverse, coming from multiple fields of study, including paleontology, anatomy, biogeography, molecular biology, and embryology. Fossil records, anatomical similarities, the distribution of species across the globe, molecular structures, and embryonic development all provide compelling support for the theory of evolution, illustrating how life on Earth has evolved and diversified over millions of years. These lines of evidence collectively reinforce the understanding of evolution as the fundamental process shaping the diversity of life on our planet.
Misconceptions of Evolution (6):
- Evolution is “Just a Theory”
- Evolution Proposes that Life Originated by Chance
- Humans Evolved from Monkeys
- Evolution is Goal-Oriented
- Individuals Evolve during their Lifetime
- Evolution is Incompatible with Religion
Clarification:
In scientific terms, a theory is a well-substantiated explanation of some aspect of the natural world that is supported by a large body of evidence.
The theory of evolution, like the theory of gravity or germ theory, is based on extensive research, observation, and experimentation. It has been repeatedly confirmed by evidence from various fields, including genetics, paleontology, and comparative anatomy.
Evolution is “Just a Theory”
Why “Evolution is ‘Just a Theory’” persists?
The word “theory” has different meanings in everyday language and in science, leading to confusion.
In everyday use, a theory might mean a speculative idea, but in science, it represents a comprehensive explanation of facts and observations.
Clarificaiton:
Evolution explains how life changes over time through mechanisms like natural selection, mutation, and genetic drift, but it does not address the origin of life itself (a field known as abiogenesis).
Moreover, natural selection is a non-random process where advantageous traits become more common in a population over time, guided by environmental pressures.
Evolution Proposes that Life Originated by Chance
Why “Evolution Proposes that Life Originated by Chance” persists?
The complexity of life and the concept of random mutations are often conflated, leading people to think that evolution suggests life is purely a product of chance.
However, the direction and adaptation of life are heavily influenced by natural selection, which is anything but random.
Clarification:
Humans and modern monkeys share a common ancestor that lived millions of years ago. Both lineages have evolved separately since diverging from this common ancestor.
Humans did not evolve from any species of monkey or ape alive today, but rather from an extinct species that gave rise to both.
Humans Evolved from Monkeys
Why “Humans Evolved from Monkeys” persists?
The visual similarities between humans and certain primates, along with oversimplified explanations of evolution, contribute to this misconception.
The idea of a direct lineage from monkeys to humans is easier to grasp but inaccurately represents evolutionary relationships.
Clarification:
Evolution does not have a predetermined direction or end goal. It is a process driven by natural selection, where organisms adapt to their environments.
Traits that improve an organism’s chances of survival and reproduction are more likely to be passed on, but this does not mean evolution is working toward perfection or complexity.
Many species remain relatively unchanged for millions of years if their environment remains stable.
Evolution is Goal-Oriented
Why “Evolution is Goal-Oriented” persists?
The idea of progress is deeply ingrained in human thinking, leading to the assumption that evolution must work toward an ultimate goal or higher form of life. However, evolution is about adaptation, not advancement toward a specific target.
Clarification:
Evolution occurs at the population level over many generations, not within an individual’s lifetime. While individuals can undergo changes (such as gaining muscle mass or adapting behaviorally), these changes are not passed down genetically. Evolution refers to changes in the genetic makeup of a population over time, driven by factors like mutation, natural selection, & genetic drift.
Individuals Evolve during their Lifetime
Why “Individuals Evolve during their Lifetime” persists?
The confusion often arises from conflating short-term adaptation or acclimatization with long-term evolutionary change.
Personal or immediate changes in response to an environment can seem like evolution, but true evolutionary change requires generational shifts in a population’s genetic composition.
Clarification:
Evolution and religion address different aspects of human experience—science focuses on the natural world and its processes, while religion often deals with moral, spiritual, and existential questions.
Many religious groups accept evolution as a mechanism through which a creator might work. The idea that evolution and religion are inherently in conflict is not a universal belief and varies widely among different religious traditions.
Evolution is Incompatible with Religion
Why “Evolution is incompatible with Religion” persists?
The perceived conflict between evolution and religion often stems from misunderstandings on both sides, as well as cultural and historical factors that have framed the two as oppositional. However, many people and religious institutions find ways to harmonize evolutionary theory with their faith.
Conclusion: Misconceptions of Evolution
Misconceptions about evolution are widespread, but understanding the scientific evidence and principles can help clarify these misunderstandings. Evolution is a well-supported scientific theory that explains the diversity of life on Earth. It is not a random process, does not propose that humans evolved from monkeys, and does not imply a goal or direction. Additionally, it occurs at the population level over generations, not within individual lifetimes, and it can coexist with various religious beliefs. Addressing these misconceptions is crucial for a more accurate understanding of biology and the natural world.
Is the branch of biology that studies genes, genetic variation, and heredity in organisms.
Genetics
It is a fundamental field that explains how traits are passed from parents to offspring and how genetic information influences the development, function, and behavior of living organisms.
Genetics
DNA
Deoxyribonucleic Acid
Is the hereditary material in almost all living organisms. It contains the instructions necessary for the development, functioning, growth, and reproduction of all known living organisms and many viruses.
DNA (Deoxyribonucleic Acid)
Structure of DNA
DNA is composed of two long strands that form a double helix. Each strand is made up of nucleotides, which include a sugar molecule, a phosphate group, & one of four nitrogenous bases: ____ (A), ____ (T), ____ (C), or ____ (G). The order of these bases determines the genetic information carried in the DNA.
STRUCTURE OF DNA:
adenine
thymine
cytosine
guanine
Function of DNA:
The sequence of bases in DNA is a code for building proteins, which are the molecules that perform most of the functions in cells. Segments of DNA that contain the instructions for making specific proteins are called genes. DNA is replicated before cell division, ensuring that each replicated before cell division, ensuring that each new cell has a complete set of genetic instructions.
The ________________ describe how genetic information is transmitted from one generation to the next.
Principles of Inheritance
Principles of Inheritance
____________, an Austrian monk, is considered the father of genetics for his work with pea plants, which led to the discovery of the fundamental laws of inheritance.
Gregor Mendel
Gregor Mendel’s Principles of Inheritance (2):
- Mendelian Inheritance
- Non-Mendelian Inheritance
Mendel’s experiments revealed that traits are inherited according to specific patterns. He identified dominant & recessive alleles, which are different versions of a gene. A dominant allele masks the expression of a recessive allele in a heterozygous individual (one who has two different alleles for a gene). Mendel’s principles of segregation & independent assortment explain how alleles are distributed into gametes (sperm & egg cells) & how traits are inherited independently of one another.
Mendelian Inheritance
While Mendel’s laws describe many patterns of inheritance, not all traits follow these simple rules. It includes phenomena such as incomplete dominance, codominance, & polygenic inheritance, where multiple genes influence a single trait.
Epigenetics, which involves changes in gene expression without altering the DNA sequence, also plays a role in inheritance.
Non-Mendelian Inheritance
Is the diversity in gene frequencies within a population. It is the raw material for evolution & is responsible for the differences among individuals in a species.
Genetic Variation
Sources of Genetic Variation
Genetic variation arises from mutations, which are changes in the DNA sequence, & from the recombination of genes during sexual reproduction.
Mutations can be caused by errors during DNA replication or by environmental factors such as radiation or chemicals. Recombination occurs during meiosis, the process that produces gametes, leading to new combinations of alleles in offspring.
Significance of Genetic Variation
- Genetic variation is essential for the survival of a species because it enables populations to adapt to changing environments.
- Natural selection acts on this variation, favoring traits that improve an organism’s chances of survival & reproduction.
Genetics & Human Health (3):
- Genetic Disorders
- Multifactorial Disorders
- Pharmacogenomics
Some diseases are caused by mutations in a single gene, leading to genetic disorders such as cystic fibrosis, sickle cell anemia, & Huntington’s disease. These conditions are often inherited according to Mendelian principles, although some may involve more complex inheritance patterns.
Genetic Disorders
Many common diseases, such as heart disease, diabetes, & cancer, are influenced by multiple genes as well as environmental factors. These multifactorial disorders are more complex to study & predict because they do not follow simple patterns of inheritance.
Multifactorial Disorders
This field studies how an individual’s genetic makeup affects their response to drugs. By understanding a person’s genetic profile, healthcare providers can tailor treatments to improve efficacy & reduce adverse effects, leading to personalized medicine.
Pharmacogenomics
Advances in Genetic Technology (3):
- Genetic Engineering
- CRISPR-Cas9
- Genomic Sequencing
Involves directly altering an organism’s DNA to achieve desired traits. This technology is used in agriculture to produce genetically modified crops that are resistant to pests & diseases. In medicine, genetic engineering is being explored for gene therapy, which aims to treat or prevent disease by correcting defective genes.
Genetic Engineering
One of the most significant breakthroughs in genetics is the development of ________, a tool that allows scientists to edit genes with unprecedented precision. ________ has the potential to treat genetic disorders, improve crop yields, & even eliminate diseases such as malaria by altering the genes of disease-carrying organisms.
CRISPR-Cas9
Advances in ________________ have made it possible to sequence entire genomes quickly & affordably. This technology is used in research to identify genetic variations associated with diseases, trace ancestry, & study the genetic diversity of populations. In clinical settings, genomic sequencing can provide insights into a patient’s risk of certain diseases & guide personalized treatment plans.
Genomic Sequencing
Conclusion: Genetics
Genetics is a dynamic & rapidly evolving field that is fundamental to our understanding of biology & the diversity of life. The study of genetics has provided profound insights into how traits are inherited, how genetic variation drives evolution, & how our genes influence health & disease. Advances in genetic technology are opening up new possibilities for medicine, agriculture, & research, offering the potential to address some of the most pressing challenges facing humanity. Understanding genetics is crucial for making informed decisions about health, policy, & the future of our species.
Is a powerful tool used in genetics to study the inheritance patterns of traits & genetic disorders within families.
By constructing & analyzing family trees, geneticists can trace the transmission of specific traits across generations, identify carriers of genetic disorders, & predict the likelihood of genetic conditions in future generations.
Pedigree Analysis
Is a diagram that depicts the genetic relationships between individuals in a family over several generations. It is a valuable tool for visualizing inheritance patterns & is used to track the occurrence of specific traits or genetic disorders.
Pedigree
Components of Pedigree (2):
Symbols
Generations
Types of Pedigrees (2):
- Standard Pedigree
- Genetic Pedigree
Shows the basic family relationships & inheritance of traits
Standard Pedigree
Includes additional information such as genetic testing results & carriers status.
Genetic Pedigree
Methods of Pedigree Analysis (7):
- Identifying Inheritance Patterns
- Autosomal Dominant Inheritance
- Autosomal Recessive Inheritance
- X-linked Dominant Inheritance
- X -linked Recessive Inheritance
- Calculating Risk
- Genetic Counseling
Applications of Pedigree Analysis (4):
- Diagnosis of Genetic Disorders
- Genetic Research
- Family Planning
- Disease Management
Limitations of Pedigree Analysis (4):
- Incomplete Data
- Complex Traits
- Genetic Heterogeneity
- Genetic Testing
Conclusion: Pedigree Analysis
Pedigree analysis is a fundamental tool in genetics that helps track the inheritance of traits & genetic disorders within families. By examining patterns of inheritance, geneticists can diagnose conditions, estimate risks, & provide valuable information for genetic counseling & family planning. Despite its limitations, pedigree analysis remains a crucial method for understanding genetic inheritance & advancing our knowledge of genetic disorders. With the integration of genetic testing & advances in genomic research, pedigree analysis continues to play a vital role in both clinical practice & scientific discovery.
