Definitions
Species are defined by similar physical characteristics
Morphological Definition
An exception to the biological definition
- Hybrids
- Single Celled Organisms
(How so?)
SI slides 10/24/2024 - for 100 pooints
Hare vs. Rabbit
Two different species!
Hares are larger, faster, and have longer ears & leg.
Rabbits are smaller, fluffier, and overall "cuter".
They even have different diets and social patterns.
Known as the father of modern taxonomy
Carl Linnaeus
What is one structural difference between DNA and RNA?
Double stranded vs. single stranded, T -> U, Deoxyribose vs. Ribose sugars, etc.
Groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups
Biological Definition
An exception to the morphological definition
- Species that look similar but aren't closely related at all!
- Individuals within the species may vary widely in appearance with each other.
SI Slide 10/24/2024 - 200 points
These are two different species! The one on the left is the American alligator, and the one on the right is a crocodile.
A quote he wrote follows, "It all comes, I believe, from trying to define the undefinable".
Charles Darwin
What is the difference between genetic drift and gene flow?
Genetic drift - happens in small populations, random fixation of genes in a population.
Gene flow - migration between populations, genes are introduced into a population (prevents speciation).
A natural taxon in classification in which members of the group share an invariant generalized or idealized pattern.
Taxonomic Definition
A critique of the evolutionary definition
- Can't observe a lineage itself ... where do you draw the line?
SI Slide 10/24/2024 - 300pts
Weasel vs. Stoat
They are different species! Stoats are bigger and have long tails with fuzzy black tips - and weasels have a shorter tail that are the same color as their body. Stoats turn white in the winter - and they have different patterns of movement.
Tenrecs and Hedgehogs are an example of the criticism to which definition of species? Why?
Morphological - look similar but are actually distantly related!
A reason that a harmful mutation may continue to persist in a population!
- Homozygous recessive ... Heterozygous carriers!
A single lineage of ancestor-descendent populations of organisms that maintain their identity from other such lineages and have their own evolutionary tendencies and historical fate.
Evolutionary Definition
A criticism of the ecological definition of a species.
- Creates too many splits between what are functionally identical populations.
SI Session 10/24/2024 - 400pts
The one on the left is a Dorper sheep, and the one on the right is a Merino sheep. These two, while looking different, are two breeds of the same species!
The Hooded Pitohui - it's poisonous!
Explain what parsimony is and what it is used for!
Phylogenetic trees - are used to determine which tree is most likely to have occurred (the least amount of trait changes). Simplest = best.
A genetically distinct population which is genotypically adapted for a specific set of environmental conditions.
Ecological Definition
- Threshold of genetic similarity to split species, but who picks the amount?
- Cannot assess species divergence based through time/fossil records.
SI Session 10/24/2024 - 500pts.
They are the same species! They are both part of the Anas Platyrhynchos species, also known as mallards! Mallards are sexually dimorphic - meaning males and females look different from each other.
What is the name of Professor Schofield's pet millipede? (Hint: It was a named picked out by her son)
Billipede!
What is a niche? Give an example from class that we used to discuss the roles that niches have in biodiversity. (We will cover more about this later)
The role an organism plays/has in an environment - can be several different things.