Biology Quiz on Evolution and Cell Theory

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Questions and Answers

What is the primary mechanism of Darwinian evolution?

Genetic drift

Natural selection (correct)

Environmental adaptations

Mutations

What does the cell theory state about all organisms?

Each organism is an independent entity, unrelated to others

All organisms are made up of both cells and tissues

All organisms are produced from non-living matter

All organisms are made up of cells (correct)

Which statement best represents a key point of modern cell theory?

New cells arise from pre-existing cells (correct)

Cells arise from spontaneous generation

Cells can be independent from tissues

All cells possess the same DNA

What is a consequence of natural selection in relation to species?

All species share a common ancestor Signup and view all the answers

What defines a cell as the smallest self-reproducing unit of life?

Cells can replicate independently and carry genetic information Signup and view all the answers

Which of the following statements about the activity of an organism is correct?

An organism's activity is influenced by the total activity of its cells Signup and view all the answers

Which characteristic is NOT part of modern cell theory?

Cells arise from non-living matter Signup and view all the answers

How does cell theory relate to evolution?

It connects all single-cell organisms through common ancestry Signup and view all the answers

Which of the following is NOT one of the basic features shared by all cells?

Chloroplasts Signup and view all the answers

What is the primary function of ribosomes in cells?

To synthesize proteins Signup and view all the answers

Which unit of measure is used to describe atomic bond lengths?

Angstrom Signup and view all the answers

Why is understanding cells important in the context of human health and disease?

Cells are the fundamental functional units of all living things. Signup and view all the answers

Which of the following is NOT a mechanism of evolution?

Environmental adaptation Signup and view all the answers

How many cells approximately are there in the human body?

37 trillion Signup and view all the answers

What is essential for natural selection to lead to evolution?

Genetic mutations Signup and view all the answers

Which concept is considered a unifying principle in biology alongside cell theory?

Evolution Signup and view all the answers

Which statement best describes differential survival and reproduction?

Some individuals produce more offspring than others due to advantageous traits. Signup and view all the answers

What is the relationship between macroevolution and microevolution?

Macroevolution is a direct result of microevolution over time. Signup and view all the answers

The structure that separates the interior of a cell from its external environment is known as what?

Plasma membrane Signup and view all the answers

How does gene flow contribute to evolution?

By facilitating the movement of traits between populations. Signup and view all the answers

Which of the following is NOT one of the broad categories of evidence supporting Darwin's theory of evolution?

Primary succession Signup and view all the answers

What does metabolism refer to in the context of cellular functions?

Chemical pathways for energy conversion Signup and view all the answers

What are traits that can be passed from one generation to the next called?

Heritable traits Signup and view all the answers

Which term describes the similarity in structure and function in different species due to common ancestry?

Homology Signup and view all the answers

What evidence of evolution describes how organisms evolve to adapt to their environments?

Natural Selection Signup and view all the answers

Why are mutations important in the process of evolution?

They serve as the raw material for genetic variation. Signup and view all the answers

What is an example of natural selection in action?

The rise of antibiotic-resistant bacteria Signup and view all the answers

Which of the following correctly reflects Darwin's concept of 'descent with modification'?

Species evolve from common ancestors with variations. Signup and view all the answers

Which factor would likely NOT influence evolutionary changes in a population?

Habitat uniformity Signup and view all the answers

Which aspect of evolution refers to the changes in inherited traits in a population over generations?

Microevolution Signup and view all the answers

What type of homology involves examining genetic sequences shared among different organisms?

Molecular homology Signup and view all the answers

Which provides evidence of evolutionary history through geographical distribution?

Biogeography Signup and view all the answers

What term describes structures that are similar due to independent evolution, not derived from a common ancestor?

Analagous Signup and view all the answers

Which of the following is an example of convergent evolution?

The wings of a bird and the wings of a bat Signup and view all the answers

What concept explains species being more closely related to other species in the same area than to those further away?

Biogeography Signup and view all the answers

The fossil record provides evidence for Darwin's theory by demonstrating:

The existence of ancient creatures that relate to modern species. Signup and view all the answers

Which major event in Earth's history greatly affected the distribution of marsupials and placental mammals?

The break up of Pangea Signup and view all the answers

Divergent evolution is primarily the result of:

Different selective pressures. Signup and view all the answers

What type of evolution illustrates similar adaptations among unrelated species in response to similar environmental challenges?

Convergent evolution Signup and view all the answers

Which of the following features is NOT characterized by convergent evolution?

Inherited from a common ancestor. Signup and view all the answers

What is the significance of stromatolites in the fossil record?

They are the oldest known fossils of cyanobacteria-like life forms. Signup and view all the answers

How long were prokaryotes the only cellular form of life on Earth?

Around 2.1 billion years. Signup and view all the answers

Which event marked a significant milestone in the evolution of life, occurring after abiogenesis?

Establishment of the RNA world. Signup and view all the answers

What was the order of key events leading to the emergence of multicellularity?

Prokaryotes, Endosymbiogenesis, Multicellularity. Signup and view all the answers

Which of the following describes the term 'endosymbiogenesis'?

The process by which eukaryotic cells originated from prokaryotic cells. Signup and view all the answers

What is a likely characteristic of the first multicellularity formed around 1.8 billion years ago?

It featured simple arrangements without true tissues. Signup and view all the answers

Which of the following entities is considered to have emerged independently as multicellular life?

Plants. Signup and view all the answers

What major event in the history of life is characterized by the increase of oxygen in the Earth's atmosphere?

Great Oxidation Event. Signup and view all the answers

Study Notes

Biology 1 - Cells, Molecular Biology and Genetics (Biol 1000)

Course offered by Dr. Michael Cardinal-Aucoin in Winter 2025
Course code is Biol 1000
Focuses on cells, molecular biology, and genetics

Evolution

Major unifying theories in biology
Darwinian evolution, including natural selection
Evidence and examples of evolution

Major Unifying Concepts of Biology

Theory of Evolution by Natural Selection
Cell Theory
Genetics
Homeostasis

Note about Theories

Everyday use: theory means a guess, or "untested speculation"
In science: a broad explanation based on many lines of evidence, aids in the generation of new hypotheses, and has withstood rigorous scientific testing

Two Major Unifying Concepts of Biology

Theory of Evolution by Natural Selection:
- Characteristics of a population change over time (pattern)
- Individuals with certain heritable traits produce more offspring than those without (mechanism)
- All species are related by descent from a common ancestor and descend from other pre-existing species
Cell Theory:
- All organisms are made up of cells (pattern)
- All cells come from pre-existing cells (mechanism)
- All single-cell organisms in a population are related to a common ancestor
- All cells in a multi-cellular organism descend from an ancestral cell and all organisms are made up of cells

Modern Cell Theory

A cell is the smallest self-reproducing unit of life
Cells make up all living things
New cells arise from pre-existing cells
The activity of an organism depends on the total activity of independent cells
Energy flow (metabolism and biochemistry) occurs within cells
Cells contain hereditary information in the form of DNA and RNA
Cells of similar organisms share similar chemical composition

Cells

All cells share certain properties, but are not identical
Plant cells (20 x 30 μm)
Animal cells (20 μm)
Bacteria (1 x 2 μm)

Different Types of Cells

Four basic features of all cells:
- Plasma membrane
- Semifluid substance called cytosol
- Genetic material (at some point)
- Ribosomes (to make proteins)
Plus metabolism (chemical pathways to convert various forms of energy into biochemical work)

Units of Measure

µm - Micrometer: 1,000,000 micrometers = 1 meter
- Strand of hair ~20-180µm in diameter
nm - Nanometer: 1,000,000,000 nanometers = 1 meter
- Wavelength of visible light (~400-700nm)
Å - Angstrom: 10,000,000,000 Angstroms = 1 meter
- Used to measure atom/bond lengths, C-H bond in methane ~1 Angstrom

Introduction to the Cell

Relative sizes of various biological entities on a logarithmic scale (e.g., atoms, viruses, bacteria, cells, eggs, humans).

Why study cells?

Cells are the fundamental functional unit of all living things
Cell theory is a unifying principle in biology
Understanding cells allows us to understand how organisms function (plants, animals, parasites, fungus, etc)
Knowledge of cells is critical to understanding human health and disease, as well as disease treatment

Nothing in biology makes sense except in the light of evolution

Evolution is a unifying theme in biology, alongside cell theory
Explains many disparate facts
All living things are the result of evolution

Other Mechanisms that drive Evolution

Artificial selection
Sexual selection
Genetic drift
Gene flow

Evolution by Natural Selection

Population differences between individuals
- Mutations, meiosis (sexual reproduction) mixes things up
Heritable traits
- Traits can be passed from one generation to the next
Differential survival and reproduction
- Some individuals leave more offspring than others
Then evolution occurs over time

Evolution by Natural Selection (alternative phrasing)

If a population has differences, traits that are heritable, and individuals leave more offspring than others, then evolution will occur over time.

It is not the strongest...

Adaptation to change is crucial for survival

How Natural Selection Works

Environmental resources are limited
- Organisms compete for space, food, mates, etc
Members of a population differ in their characteristics
Some characteristics provide an advantage in competition
- Individuals with these traits live longer and produce more offspring.

Evolution by natural selection

If a population has differences between individuals, those traits are heritable and the result is differential survival and reproduction, then evolution occurs over time. This is a restatement that's a bit more concise.

Natural selection acts "sees"

Genotype: The genetic makeup of an organism
Phenotype: Observable characteristics of an organism

Evolution = Genotype Phenotype Environment

Explains how genotype, phenotype, and environment interact in evolution.

Macroevolution = Microevolution x Time

Cumulative effects of small changes over millions of years lead to major evolutionary changes

The Vastness of Evolutionary Time

Earth is 4,600,000,000 years old
Multiple timescales (human generations, mouse generations, fly generations, bacteria generations) are presented in relation to Earth's age.

Macroevolution=Microevolution x time

Over time, phenotypic differences accumulate producing major transitions in evolution
Even complex organisms evolve from single cells over millions of years

Evidence for Evolution by Natural Selection

Lots of examples of evidence demonstrating evolutionary change are provided, but the specific details are not summarized here, primarily due to the significant amount of image data displayed.

Evidence for Darwin's Theory (Homology)

Homology: Similarity resulting from a common ancestry
- Anatomical, Embryological/developmental, Genetic/Molecular examples including vestigial traits

Homology: Vestigial Genetic/Molecular

Icefish example: a species of fish that lives in frigid Antarctic waters and lacks hemoglobin, yet retains part of the hemoglobin gene. This is a vestigial characteristic.
Example of different types of hemoglobin genes from various species on phylogenetic tree that also shows evolutionary relationships.
Complete loss of the 24th pair of chromosomes in humans from great ape ancestry is a possible example of this concept

Convergent Evolution

When characters are similar but are not derived from a common ancestor.
Analogous characters develop due to adaptation to similar environments in unrelated groups

Biogeography

Species distributions can be explained by evolution
Species tend to be more closely related to those in the same area
Common ancestors adapting to nearby habitats
Pangea example of continental drift leading to isolation and the evolution of different species, including marsupials in Australia

Fossil Record

Oldest fossils from 4 billion years ago
Cyanobacteria (blue-green algae) and Precambrian fossils
Oldest cyanobacteria-like fossils are 3.5 billion years ago
Cyanobacteria are larger than most bacteria - secrete a thick cell wall
Often form layered structures (stromatolites) or round ones (oncolites)

Fossil record examples of multicellularity

First single-celled eukaryotes from 1.8 billion years ago (Parfreya et al. 2011)
Prokaryotes were the only cells for over 2 billion years
True multicellularity appeared around 1.8 to 1.5 billion years ago
Many independent origins of life forms (plants, animals, fungi, red algae, brown algae, myxomycetes etc)

How is evolution relevant to cell biology?

Explain how cells evolved
Detail the structure/function of cells
Explain how cells adapt to different environments/circumstances.

Main Events in the Evolution of Cells

Abiogenesis
Protocells
RNA world
Prokaryotes
Endosymbiosis
Eukaryotes
Multicellularity

Abiogenesis

Prebiotic synthesis: formation of life's molecules under prebiotic conditions
No fossil records, but laboratory experiments can replicate early Earth conditions.
Living things are composed of carbohydrates, lipids, proteins, and nucleic acids

Protocells

Formation of lipids (phospholipids) in aqueous environments (water) result in the instant creation of micelles and liposomes

RNA world

RNA's properties of storing information (similar to DNA) and acting as enzymes (similar to protein)
Current scientific evidence (experiments) supports the idea that RNA came before DNA in early life forms.

Prokaryotes

Small, simple cells without internal compartments
Evolved most of the biochemistry present in all life forms
- DNA replication, the genetic code, protein synthesis via transcription/translation, photosynthesis, anaerobic/aerobic respiration
Evolved into eubacteria and archaea

Endosymbiosis

Ancestral organelles (e.g., mitochondria, chloroplasts) were free-living prokaryotes
These prokaryotes were engulfed by larger cells and became incorporated into the host cells

Eukaryotes

Compartmentalization (membrane-bound organelles)
Cellular trafficking (endomembrane system)
Larger cells, true multicellularity
Mitosis/meiosis (increased genetic diversity for natural selection)

Multicellularity

First came about 2.7 billion years ago and took off around 1 billion years ago
Key advantage is size
Competition for resources (food)
Defense against predators
Division of labor