General Biology I - BSC 1010C - Chapter 1: Themes in the Study of Life

What is natural selection? How does it relate to the theory of evolution?

- Natural selection is a process in which individuals with certain heritable traits survive and reproduce at a higher rate than do other individuals because of those traits. - This relates to evolution because the inherited traits are passed on through sexual reproduction until only those favorable traits exist. The traits are evolving with time through natural selection and inherited traits that allow for the organism to survive and reproduce successfully.

What are the taxonomic groups that we classify all living organisms into? Which is the most general? The least?

- The eight taxonomic groups that we classify all living organisms into are Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species. - The most general group is the Domain, and the least general is the Species.

What is an adaptation? How are adaptations passed onto subsequent generations?

- Adaptations are beneficial changes in an organism's genetic code; they give organisms an advantage in their environment. - Adaptations are passed onto subsequent generations through sexual reproduction and are determined by natural selection.

Explain what the phrase "unity and diversity of life" refers to in the context of chapter 22. How could this phrase be applied to organisms that are distantly related? Closely related?

- All living things share one common ancestor and they all descended from that one organism; however, we are all diverse and different due to the process of evolution. - "Diversity" refers to our differences in genetic traits and characteristics and the term can also be applied to organisms that are distantly related. - "Unity" refers to organisms that are closely related, ones that have common ancestry and characteristics.

What is an anatomical homology? Why does an anatomical homology serve as evidence of descent with modification and natural selection?

- An anatomical homology refers to the similarities between the structure of two organisms. Anatomically homologous organisms have similar bodies or body parts in common. - This serves as evidence of descent with modification and natural selection because it shows that at one point we were common ancestors; over time, these traits changed over time as environmental conditions differed.

What is artificial selection? How does it occur and why? Give some examples. Why does it serve as evidence of evolution?

- Artificial selection is when humans modify other species over generations by selecting and breeding individuals that possess desired traits. This occurs because people want certain things to be a certain way, so they scientifically modify it to possess those desired traits. - This serves as evidence to evolution because if organisms are "fit" and survive/reproduce after they are modified, then they reproduce and will pass their traits to future generations. - One example of artificial selection is the practice of dog breeding.

What is biogeography? How does it aid us in understanding evolution?

- Biogeography is the scientific study of the past and present geographic distributions of species. - The theory of evolution is supported by biogeography through evidence such as the species on earth being distributed around the planet based on their genetic relationships to each other.

Describe descent with modification. Why are cells, DNA, mutations, sexual reproduction, and reproductive success important to this concept?

- Descent with modification: Passing traits from parent to offspring, a line of ancestry that means change. As living organisms live and evolve they slowly change over time. - Cells: Carry the DNA - DNA: Genetic makeup; includes instructions to make proteins. Small modifications occur in DNA every time an offspring descends from its parents. These modifications happen because of replication and recombination of the parents' DNA and because of random mutations in the resulting DNA of the offspring. - Mutations: Changes in DNA. Random mutations occur when parents reproduce resulting in the DNA of the offspring changing. - Sexual reproduction: Small modifications occur in DNA every time an offspring descends from its parents. - Reproductive success: To evolve and change over time, you need to be able to reproduce. This allows the mixing of DNA and mutations to both further the existence of an organism.

Natural selection describes how the living and nonliving components of the natural environment influence the success (or lack thereof) of a population of organisms. Describe how an environment can dictate the success of a population of organisms and describe the random changes the organisms can undergo to improve their ability to survive and reproduce. Do living things will themselves or initiate adaptations to an environment?

- In a certain environment, some organisms have variations that benefit their survival over other organisms with different traits. - For example, if there are 5 black beetles and 2 blue beetles and the birds only eat the black ones, the blue ones have a better chance of surviving and passing on their genes. This is a mutation that occurred that helped the beetles survive. This is natural selection because the environment unconsciously decides what beetles are eaten and which ones are not. - Living things cannot initiate evolution themselves since the process happens over time; however, they are able to adapt to their environments if they have advantageous traits.

To test a hypothesis you need to start by designing an experiment, describe the significance of each of the following in the experiment: independent variable, dependent variable, controlled variables, treatment group, control group, and replication (In my opinion, it is easiest to do this in the context of an example.).

- Independent variable: The changing factor of an experiment. - Dependent variable: The factor being measured that is predicted to be affected by the independent variable. - Controlled variable: A variable that remains unchanged or held constant to prevent its effects on the outcome and therefore may verify the behavior of and the relationship between the independent and dependent variables. Controlled variables are important in scientific experiments to test the validity of the results. - Controlled group: In a controlled experiment, a set of subjects that do not receive the specific factor being tested. This is the group that we already know what is going to happen. - Treatment group: The group that is experiencing the change, where we collect our data from. - Replication: The ability to reproduce an experiment several times; it is determined by the number of resources you have.

Compare and contrast inductive reasoning and hypothesis-based science.

- Inductive reasoning and hypothesis-based science are both methods of explaining science and coming to conclusions. - Inductive reasoning involves generalizations through repeated observation (specific to broad). - Hypothesis-based science employs the scientific method to provide explanations to more specific questions (broad to specific).

What role do mutations and sexual reproduction play in evolution?

- Mutations are mistakes in DNA that are passed from generation to generation; they lead to different types of proteins being made in the next generation. - In the process of sexual reproduction, the parents pass down their genes to their offspring; the offspring inherits new combinations of variations of those genes, leading to differential inheritance.

What are the characteristics of living things?

- Order: Living things spend their entire lives using energy to accumulate matter and to organize that matter. - Response to the environment: The way that organisms respond to changes in their environment often reflects how they adapt to their habitat, etc. - Reproduction: All living things emerge from a previous generation of living things through the process of reproduction. - Regulation: Living things evolved to have several methods to regulate their systems (i.e. homeostasis) as a result of their environment. - Growth and development: Unicellular and multicellular organisms have different processes of growth and development. - Energy processing: Refers to an organism's ability to take in one form of energy and change it into another. - Evolution: The overarching theme of life; explains the unity and diversity of life.

How do eukaryotic cells differ from prokaryotic cells, how are they similar, what type of organisms have prokaryotic cells, which have eukaryotic cells?

- Prokaryotic cells have no nucleus and less compartmentalization; they are generally less complex than eukaryotic cells; they are usually unicellular. - Eukaryotic cells are more complex, have membrane-bound organelles and a nucleus, and are more compartmentalized; they can be either unicellular or multicellular. - Both types of cells contain DNA and are the basic units of life. - Prokaryotes are found in the domains Bacteria and Archaea, while eukaryotes are found in the domain Eukarya.

How are reductionism and systems biology different? Similar?

- Reductionism and systems biology are both ways to figure out how an organism works and interacts with its environment. - Reductionism: The process of taking something apart to figure out how it works. - Systems biology: Focuses on complex interactions with biological systems and is generally a more holistic approach.

What is science, what is biological science?

- Science is an analytical approach to understanding the natural world; it is the way we go about establishing knowledge and information about the world around us. - Biological science is the scientific study of life, specifically dealing with the living world and organisms. In biology, the scientific method is applied to living things such as plants or animals.

Identify the different levels of biological organization; identify and describe an emergent property.

- The different levels of biological organization are atoms, molecules, organelles, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems, and the biosphere. - Emergent property: A complex property that is present at one level but not present at simpler levels; an important example of an emergent property is life itself.

What forms of natural evidence led Darwin to the development of his hypotheses? Describe other evidence that emerged after Darwin's life.

- The form of natural evidence that led Darwin to the development of his hypothesis was endemic species, animals of the same species with different traits and characteristics, different places had different organisms. - Also, the fossil record had evidence that led him to describe the "Origin of Species". He founded his hypothesis when he traveled to the Galapagos on the Beagle ship. - Evidence that emerged after Darwin's life mainly has to do with DNA, such as vestigial organs.

What are the three domains of life, give a living example of each?

- The three domains of life are Bacteria, Archaea, and Eukarya. - The domain Bacteria includes cyanobacteria, mycoplasmas, Gram-positive bacteria, and Gram-negative bacteria. - The domain Archaea includes prokaryotes that live in extreme environments, such as halophiles and methanogens. - Eukarya includes eukaryotes such as protists, fungi, plants, and animals.

What are vestigial structures? How do they come about?

- Vestigial organs are structures of living things that have lost or reduced function. - As the population changed due to natural selection and adaptations, the structures became more and more useless however they are still shown to be there, just not the same.

Identify and describe the steps of the scientific method.

1) Observe the situation. 2) Ask a question related to your observations. 3) Turn that question into a testable hypothesis (a tentative answer to that scientific question) and predict the outcome of your experiment. 4) Test the hypothesis by designing and performing an experiment. 5) Analyze the results. 6) Evaluate your hypothesis; does the data support it?

What is an acquired trait, can it be inherited?

An acquired trait is something you learned and cannot be inherited. For example, if you originally had blonde hair and dyed it brown, that trait will not be passed down to your children because it is not in your genetic code.

What is artificial selection, what is the significance of the term "artificial"?

Artificial selection is the selective breeding of domesticated plants and animals to encourage the occurrence of desirable traits. The significance of the term artificial is that it is made or produced by human beings rather than occurring naturally, often copying something natural.

What does it mean to be endemic?

Endemic means that a species is found nowhere else in the world, one that is unique to a geographical location.

Explain what it means for a hypothesis to be "falsifiable".

If a hypothesis is falsifiable, it means that the hypothesis can be tangibly proven right or wrong. A hypothesis needs a way to be measured if it is true or false because you cannot measure certain things.

How do organisms change from one generation to the next?

Organisms change from one generation to the next through natural selection, sexual reproduction, and mutations.

How are descent with modification and natural selection related?

Over time, natural selection may increase the frequency of adaptations in a population that are favorable in a given environment; this in turn leads to descent with modification because those traits are passed through many generations.

What is the "Origin of Species"?

The "Origin of Species" is Darwin's book where he amassed evidence that descent with modification by natural selection explains three broad observations about nature: the unity of life, the diversity of life, and the striking ways in which organisms are suited for life in their environments.