Test 1 - Genetics & Evolution

test: 2025-07-11

What is Evolution?

Evolution is the process by which a population of organisms changes over TIME.

Who was Charles Darwin? What are some of his discoveries?

Man who came up with the theory of evolution. Suggested Species change over time and all have a common ancestor. Realized there were many different types of plants and animals that were never seen before

What book did Darwin contribute to?

"Origin of Species" by Natural Selection.

What is "fitness" in the context of evolution?

Physical traits and behaviors that enable them to survive and reproduce.

What is Artificial Selection?

Humans artificially selecting the best plants for crops and the best animals for breeding.

How does Artificial Selection work? (Use Farmers as an example)

Farmers noticed natural variations in plants and animals and selected the ones with variations that best suited the farmer's needs.

What did Malthus suggest about human population? How did it influence darwin?

If populations keep growing, we will run out of space and food. This led to darwin realizing POPULATIONS ARE CONTROLLED - But he wondered what determines who dies and who survives

What is Microevolution?

Microevolution is the change in allele frequency in the gene pool of a population over a short period of time (few generations).

What is Macroevolution?

Macroevolution is the change in allele frequency of a population over a LONG period of time (many generations), resulting in new species. RESULTS IN VARIATIONS NOT NEW SPECIES

What are the 5 drivers of evolution?

1. Natural Selection, 2. Mutation, 3. Genetic Drift, 4. Gene Flow (Bottleneck Effect), 5. Non-Random Mating.

What is a mutation? What role do they play in genetic variation?

A mutation is a MISTAKE when DNA is being read. Mutations are a SOURCE of variation that helps a population adapt to new surroundings.

What is the nature of most mutations? (Are they normally good? Bad?

Most mutations are neutral, meaning they do not harm or hurt the individual and usually go unnoticed.

What is Genetic Drift?

An allele can increase in a population by CHANCE, and not because the allele codes for a trait that makes the individual better suited for its environment.

What is the Bottleneck Effect (Gene Flow)?

Migration of organisms can introduce new alleles to a population.

What is Non-Random Mating?

Occurs when individuals choose their mates compared to mating being random.

What are Genes? What do they code for?

Specific segments of DNA found in specific places on the chromosome. Genes code for how to make PROTEINS that your cells need.

What do proteins determine?

Some of these proteins determine what you will look like.

What makes a blood cell different from a muscle cell? (Or just any cell in general)

Only certain genes are used in each cell. They only read certain parts of the DNA and make those proteins ONLY

What are Enzymes?

Proteins that speed up your body's chemical reactions. catalyst

What are Hormones?

Chemical messengers that travel through the body.

What are Mutations?

Changes in DNA when it is being read.

What are the 3 types of Mutations? What is a Frameshift mutation?

1. Base deletion (one base is deleted),

2. Base addition (one extra base is added),

3. Base substitution (one base is substituted for another).
FRAMESHIFT: A base deletion or addition that affects everything after it.

What are homologous chromosomes?

Chromosome pairs where one chromosome is inherit from the mother and other the father

What is an Allele? How many alleles does an individual have for each gene?

An allele is a form of a gene that determines the type of trait.One allele on one chromosome from dad and one allele on another chromosome from mom.

What is a Homozygous/ Heterozygous pair?

HOMOZYGOUS: If the two alleles are the same.

HETEROZYGOUS: If the two alleles are different.

What is Complete Dominance?

When the dominant allele completely masks the effects of the recessive allele.

What is Incomplete Dominance?

When the dominant allele mixes with the effects of the recessive allele, thereby creating a new intermediate phenotype.

What does DNA stand for?

Deoxyribonucleic acid.

Where is DNA located in the cell?

In the nucleus.

What are the four bases in DNA?

Adenine, Thymine, Guanine, Cytosine (AT, CG).

What happens when DNA needs to reproduce?

The DNA will start to unwind.

Recite Cell Theory

1. Cells are the basic unit of life
2. All living things are made of one or more cells

3. All cells come from pre-existing cells

What is the Cell Membrane?

Outer boundary of cell; separates the cell from its environment.Controls what goes in and out of the cell; provides protection and support. It is also flexible.

What is the Nucleus?

Brain of the cell, located within the middle of the cytoplasm. Controls all of the cell's activities; controls which proteins are made.

What are the 3 parts of the Nucleus?

1. Nuclear membrane, 2. Nuclear pore, 3. Nucleolus.

What is the Cytoplasm?

The matrix (fills space), inside the cell membrane but outside the nucleus. Contains all the organelles outside of the nucleus.

What are Ribosomes?

Small grain-like bodies (ribosomes are NOT covered in a membrane) attached to the ER. They make PROTEIN and get instructions for protein production from DNA.

What is the Endoplasmic Reticulum (ER)?

Folded, tube-like membrane from the nuclear membrane.Moves materials (especially proteins) around the cell; acts like a conveyor belt.

What are Golgi Bodies?

Bag of flat, membrane-covered sacs. Stores, sorts, and modifies proteins from the ER; to do different jobs.

What is the Cell Wall?

Outer boundary of cell; separates the cell from its environment. Provides protection and support for the cell. (Only found in PLANT cells).

What is the Mitochondria?

Rod-shaped structures that have a folded inner membrane within an outer membrane. Releases ATP from the sugar (glucose) in food by combining it with oxygen (cell respiration). Also called the POWERHOUSE of the cell.

What are Chloroplasts?

(Found in PLANT cells!) Contains chlorophyll and uses sunlight to make glucose via photosynthesis

What is a Vacuole?

Large, round, fluid-filled sac. that stores food, water, wastes and other materials

What are Vesicles?

Membrane covered sacs that form off the end of the ER. Transport new proteins to the Golgi body for further processing and export out of the cell.

What is Traditional Breeding?

Crossing plants and selecting offspring. (Almost all crops) Many genes affected

What is Mutagenesis?

Exposing crops to chemicals or radiation. Random changes in genome and are unpredictable

What is RNA Interference?

Switching off selected genes with RNA. Very precise.
RNA interference (RNAi) is a cellular mechanism that uses RNA molecules to silence gene expression. It's a natural process triggered by double-stranded RNA (dsRNA) and is involved in various biological processes, including defense against viruses, regulation of gene expression, and development. RNAi works by degrading or blocking the translation of messenger RNA (mRNA) molecules that match a specific DNA sequence, effectively turning off the gene that produces that mRNA. 

What are Transgenics?

Inserting selected genes using recombinant DNA methods.

How have Humans genetically modified foods for centuries? What are some examples?

Via selective breeding. Corn and species of dog.

What is Recombinant DNA? What can it be used to make?

Essentialy its a DNA that is created by combining genetic material from two different sources. It can be used to make Insulin and growth hormones

What can Hybrid Crop Species do? (GMO Crops)

Produce more disease or extreme weather resistant, increasing production of food worldwide.

Give an example of how alleles determine a trait.

Hair color is the gene; brown, black, and blonde hair are alleles. Eye color is the gene; green, hazel, brown, and blue eyes are alleles.

How many alleles does an individual have for each gene? (Think Parents)

An individual will have two alleles for each gene: one allele on one chromosome from dad and one allele on another chromosome from mom.

How would an incomplete dominance scenario differ from complete dominance in terms of observable traits (phenotypes)?

In complete dominance, the dominant allele fully masks the recessive allele, resulting in only two possible phenotypes (e.g., black or blonde hair). In incomplete dominance, the heterozygous genotype results in a third, intermediate phenotype that is a blend of the two homozygous phenotypes (e.g., a mix of colors like a red flower crossed with a white flower producing pink flowers).

Describe the basic structure of DNA

DNA structure is a double helix (like a twisted ladder). The sides are made of a sugar-phosphate backbone. The "rungs" of the ladder are made of nitrogenous bases.

What is a chromosome?

A chromosome is DNA tightly packed around proteins. Humans have 23 pairs of chromosomes, totaling 46 chromosomes.

Compare and Contrast Microevolution and Macroevolution.

Both microevolution and macroevolution describe changes in allele frequencies over time. Microevolution refers to small-scale changes within a population over a short period, potentially leading to variations within a species. Macroevolution refers to large-scale changes that occur over long periods, leading to the formation of new species.

What is Variation (even within a species!), and why is it necessary for evolution by natural selection?

The members of the population must vary from each other. They cannot all be identical. Because then they would all either survive or all die. Some of these variations will affect how well an organism is adapted to their environment.

List the two requirements for evolution by Natural Selection.

Variation (members of a population vary). 2. Heritable Trait (variations are genetically based and can be passed on).

What did Jean Baptiste de Lamarck suggest about living things? What was a key flaw in Lamarck's theory of evolution regarding trait inheritance?

Jean Baptiste de Lamarck suggested that living things CHANGE over time.

However, he was wrong when he predicted living things change because they "want" to

What did Charles Lyell suggest about the Earth? How did it influence Darwin?

Suggested the earth was very OLD when most people thought the Earth was only a few thousand years old.

Supported Darwin- For evolution to occur, earth needed to be millions of years old

What is the relationship between fossil layers and age?

Fossils in older layers are more primitive than those in upper layers.

What do fossil records show about evolutionary lineage? is it complete?

The fossil record can give us an idea of the evolutionary lineage of different organisms, however, it's very incomplete.

What is a fossil?

A fossil is ANY remains left behind by a living thing (not just skeleton).

What is a trace fossil?

A trace fossil are non-body remains such as footprints or animal dung (Coprolite/ animal poop)

What is Relative Dating?

Relative Dating can tell us how old Earth layers are RELATIVE to each other. ESTIMATE. the deeper the older.

What is Absolute Dating? How do we find the exact age of rock layers for absolute dating?

Absolute dating can be found using many methods:

• radiometric dating: radiocarbon dating, potassium-argon dating, etc.

• Fission tracking dating: tracking using the spontaneous fission of Uranium-238. Higher track densities of the fission tracks per unit area means older. Used for dating volcanic glasses, apatite, and other minerals found in rocks and sediments. 

• Thermoluminescence Dating: the amount of light emitted by a material when heated (they release stored energy as light) is related to the time elapsed since the material was last heated or exposed to sunlight. Used for dating pottery, ceramics, and sediments. 

• Electron Spin Resonance (ESR) Dating: measures the amount of trapped (due to exposure to natural radiation) electrons in materials. Used for dating tooth enamel, carbonates, etc. 

• Dendrochronology: uses the annual growth rings of trees to determine age.

• Ice Core Dating: Ice cores contain annual layers that can be counted to determine the age of the ice.

What is Radiometric dating?

Radiometric dating is the process of determining the absolute age of a sample based on the RATIO of parent isotope to daughter isotope.

How it works:

1. Many elements have radioactive isotopes, which are unstable and decay into other elements over time. 

2. Each radioactive isotope has a specific half-life, which is the time it takes for half of the isotope to decay. 

3. Radioactive decay often involves a series of steps, where one isotope decays into another, eventually ending with a stable isotope. 

4. Radiometric dating techniques involve measuring the amounts of parent and daughter isotopes in a sample using specialized equipment. 

5. By knowing the half-life of the isotope and the ratio of parent to daughter isotopes, scientists can calculate the age of the sample. 

How does embryology provide evidence for evolution?

Early development (embryos) are very similar; all vertebrates have gill slits and a tail in their early embryo stage.

What are Homologous Structures?

Structures in organisms that share a COMMON ANCESTRY and are similar, but adapted to do different tasks

What are Analogous Structures?

Structures without a common ancestor, but are similar in function and DIFFER IN STRUCTURE (eg. Insect and Bird Wing)

What are Vestigial Structures?

Vestigial Structures are organs or structures that had a function in an early ancestor but are useless now

What is a species?

A species is a group of populations whose members have the potential to interbreed in nature and produce fertile offspring.

What is the Biological Species Concept?

BIOLOGICAL CONCEPT: Populations are defined as two different species when individuals from each population cannot produce fertile offspring.

What is the Morphological Species Concept?

MORPHOLOGICAL CONCEPT: Grouping species based on physical structures. Important when looking back in time (e.g., fossils).

What is Allopatric Speciation?

Allopatric Speciation is the evolution of a new species from a surviving ancestral species while both inhabit DIFFERENT geographic locations.

What is Sympatric Speciation?

Sympatric Speciation is the evolution of a new species from a surviving ancestral species while both inhabit SAME geographic location. Can be due to behavioral, temporal, habitat isolation or genetic incompatibility.

What is Co-Evolution?

Process that gives rise to two (or more) species that affect each other's evolution. - Hummingbirds and ornithophilous Flowers evolve to be together

What is Adaptive Radiation?

Adaptive Radiation/Divergent Evolution is a process that gives rise to many species that appear different externally but are similar internally.

What is petrification?

A type of fossilization where the organic matter is replaced by minerals, turning it into stone

What is a niche in biology?

The role an organism plays in its ecosystem and how it interacts with stuff. (eg. Eating nuts and seeds)

What is CRISPR?

CRISPR is a gene editing tool that allows for precise and targeted modifications to DNA

Divergent Evolution

DIVERGENT - Two or more species with the same ancestor become different over time

Convergent evolution

CONVERGENT - Different species (no common ancestor) evolve similar traits because of environment