Lecture II: Connectivity and Diversity of Life Flashcards
What are the three types of interactions in an ecosystem?
Interactions between individuals of the same species
Interactions between individuals of different species
Interactions with the physical environment
name some examples of interactions between individuals of the same species
Competition for resource and mates; cooperation.
Name examples of interactions between individuals of different species:
Competition (food and resources), herbivory, predation, parasitism, mutualistic symbioses
Name some examples of interactions with the physical environment.
Weather conditions, seasons, availability of resources (water; places to live)
Summarize the ecosystem energy flow
(look at the diagram)
Energy flow is linear
Energy is lost from the system as it moves through the web in the form of heat.
All levels are connected to decomposers.
Physical environment: sun, etc.
Producers (plants): convert energy into chemical energy
Consumers (animals): eat chemical energy from producers and/or other consumers
Decomposers: Obtain energy from absorption of organic molecules from dead organisms or their tissues
Summarize the nutrient cycling in an ecosystem.
(look at the diagram)
Nutrients are never lost from an ecosystem
Physical Environment: Reservoir for water and nutrients (carbon, nitrogen, phosphorous)
Producers: Assimilate nutrients from physical environment and use it to grow and develop.
Consumers: Ingest nutrients from producers and/or other consumers to grow and develop.
Decomposers: Breakdown complex organic molecules into simpler inorganic forms
How are living organisms connected?
They are connected through shared ancestry.
When we compare different types of living organisms that exist today we find many similarities in form. These similarities often exist due to shared ancestry and the passing down of genetic traits.
What are the roles of Genes?
Specific segments of DNA are called Genes and each gene holds the instructions to make one or a few proteins. Each protein is responsible for one or more traits within the organism
What is evolution? What are the two mechanisms?
Descent with modification in characteristics. In essence, changes in genetic traits with successive generations.
- Vertical descent with mutation (over generations)
- Horizontal gene transfer (same generation)
What is vertical descent with mutation?
The traditional view of evolution proposed by Darwin.
New species evolve from pre-existing species through the accumulation of new beneficial mutations which are passed down from one generation to the next over a long period of time.
What is mutation?
Generated by a genetic error that causes an alteration of a trait
What is natural selection?
If a mutation causes an alteration to a trait that allows the organism to survive and reproduce better, it will become more prevalent and be passed down from generation to generation. This is vertical descent with modification (mutation) by a process called Natural Selection.
What is Horizontal Gene transfer?
Evolution through the exchange of genes between 2 different species.
This happens within the lifetime of the organisms (during one generation) not over multiple generations. Most commonly occurs between unicellular organisms.
Organisms such as bacteria can transfer genetic material between cells. Occasionally this occurs between different species.
Why is diversity important?
Diversity gives stability by making us better at coping with changes in our environment.
A population that is genetically diverse will have a better chance of surviving a change in the environment than one that is all the same. This is also true of ecosystems that have rich species diversity compared to those that do not.
What is Taxonomy
Branch of biology that attempts to understand the relationship between different types of living organisms in terms of their evolutionary history.
