Topics 1 and 2: Biodiversity and Systematics Flashcards
1
Q
Why is there an urgency to study biodiversity?
A
Human activities are threatening it, the loss of biodiversity has implications for humans.
2
Q
What are some threats to biodiversity?
A
- resource exploitation
- conversion of land
- pollution
- transport of species
- global climate change
3
Q
What are some direct benefits of studying biodiversity?
A
-can be useful in the production of drugs and can have agriculture value (source of food)
4
Q
What are some indirect benefits of studying biodiversity?
A
- ecosystem services (biogeochemical cycles, nutrient cycling, H2O cycling, preventing soil erosion, regulating climate-carbon cycle)
- ecotourism
5
Q
Population
A
a group of individuals of the same species
6
Q
Community
A
several populations living together
7
Q
Ecosystem
A
-is defined as a community+physical environment
8
Q
What are the levels of biological organization?
A
- the biosphere
- ecosystems
- communities
- populations
- organisms
- organs and organ systems
- tissues
- cells
- organelles
- atoms and molecules
9
Q
Theories
A
- Unifying explanations of the natural world
- have withstood rigorous scientific testing, challenging, and debate
- does NOT mean hypothesis
eg: cell theory, gene theory, theory of evolution
10
Q
Laws
A
-is universally true and exception free (is very rare in biology)
11
Q
Proximate Questions
A
-deal with the mechanism of things and do not always require evolutionary explanations
12
Q
Ultimate Questions
A
-are concerned with the evolutionary origins and functions
13
Q
Observation (discovery science)
A
-before we make a hypothesis, we first must observe things-making observations allows us to undergo hypothesis testing
14
Q
Induction
A
- inference of a general law from specific observations
eg: all organisms are made of cells
15
Q
Natural History
A
- patterns observed that are documented
- documentation of appearance, behavior, distribution, etc of organisms
16
Q
What is a hypothesis?
A
- is a possible explanation for an observation
- knowledge-based
- testable and falsifiable (via observations and experiments)
17
Q
Scientific Method
A
-evidence-based inquiry for understanding life
-hypothetico-deductive science
-uses deductive reasoning
“if…, then…” logic eg: if spiders who match backgrounds can catch more prey, they will survive and reproduce more”
-method is flexible
18
Q
Deductive reasoning
A
-taking answers from a specific test and applying more generally
19
Q
What are the characteristics of life?
A
- order (highly organized and composed of more than 1 cell)
- regulation and energy processing (metabolism)
- growth and development
- reproduction
- response to stimuli (environment)
- evolutionary adaptation
eg: seeds before germination are not living organisms, viruses are not living because need host
20
Q
What are different ways in which we can catalog the diversity of life?
A
- Aristotle’s scala naturae
- Linnaeus
- Modern Systematics
21
Q
How did the Scala Naturae organize species?
A
- species are fixed and unchanging
- they are created perfectly matched to their environment
- organized by complexity with man on top
22
Q
What are some shortcomings with the scala naturae?
A
-if species are perfectly matched to their environment, how do they go extinct?
23
Q
Nomenclature
A
a system of rules for naming things
24
Q
Taxonomy
A
the practice of naming and classifying organisms
25
Systematics
the theory (and practice) of classifying organisms based on evolutionary history (phylogeny)
26
Problems with common names of organisms
1. there can be different names for the same species
- common names differ among countries and languages, the same geographical place an also have multiple names for the same species
2. same name for different species
3. common names can imply relationships taht do not exist
27
Main characteristics of the Linnean System
- use of Latin as the universal language of scientific nomenclature
- use of unique binomen as the name of each species
- classify and group species using hierarchical categories based on relatedness and/ or similarity
- did not believe in evolution (but there ended up being some consistency with evolution theories)
eg: birds were not classified with reptiles even though they evolved from them
28
Binomen
- a name having 2 parts (genus name and specific name)
- always italicized
- the two parts make up the species name
29
What is the Linnaean system of classification from least related to most related?
- domain is not considered in this system
- kingdom
- phylum
- class
- order
- family
- genus
- species
30
Why is the kingdom classification no longer used?
-protists have evolved into animals, plants, fungi, and bacteria, this means protists superede these other kingdoms (are not their own seperate kingdom), therefore the kingdom story is innacurate
31
Cladistics
A method of classifying organisms based on hypotheses of common ancestry
32
State an example of how Linneaen classifications are NOT consistent with cladistics
Under Linneaen classification birds/aves is its own different category, while using modern-day systematics, reptiles and birds would be grouped together because birds are evolved from reptiles
33
Phylogenetic Trees
- evolutionary trees that show the evolutionary relationship between organisms (past and present), between common ancestors and descendants
- are hypotheses for evolutionary relationships-reflects our current understanding of how things came to be
34
What is the goal of Phylogenetic trees?
To organize species into groups with common ancestry
35
Taxon/Taxa
Is a named group at any level of classification
36
Clade
- A valid group includes the ancestor at any node and everything above or beyond it (descendants)
- ie: anything branching from a certain node= clade
37
What do the branches of a phylogenetic tree represent?
-length of branches and show how different species are eg: number of DNA base changes over time
38
Sister taxa
- taxa that are derived from a common ancestorial node (most immediate ancestor)
- are each other's closest relatives
39
Polytomy
- is unresolved
- we don't know the history of the group, therefore there's a split into 3 or more directions from a common ancestor (equal support for all hypotheses)
40
Node
-is a branch point where a speciation event occurred
41
What sort of information is collected when building phylogenetic trees?
-morphology, behavior, DNA sequences, and biochemistry
42
In-group
Group whose relationships we are interested in untangling
43
Out-group
One or more taxa that are distantly related to the ingroup, but that have diverged from it at an earlier time
-forms a basis of comparison
44
Character
- a type of structure, behavior, DNA sequence, etc
| eg: eye color
45
State
- a manifestation of that character
| eg: eye color
46
Parsimony
-construct a set of nested relationships that minimizes the number of times a character changes state
47
Occam's Razor
- states that no more assumptions should be made than necessary (go with the simplest explanation)
- "if one must postulate a number of unknowable events (changes in character states), the best hypothesis is one requiring the fewest postulates"
48
How is parsimony related to evolution?
-choose the phylogeny that requires the fewest number of evolutionary events (because it is more probable)
49
Event
Change from an ancestral state
| eg: gaining a new trait or losing an old one
50
Synapomorphy
- is a shared, derived state
- same morphology compared to other groups (creates clades, differentiates from other clades)
- useful for reconstructing phylogenetic relationships
51
Symplesiomorphy
- is a shared, ancestral state
| - shared by all members of a clade and does not distinguish the clade from other clades
52
Homologous Character States
- look the same and have the same evolutionary origin
- character shared in present species that was also present in a common ancestor
- cladistics work best when all character states are homologous
eg: having things with no liberal function eg: whales with legs are homologous traits from evolution
53
Analogous Character States
- appear the same but actually evolved independently (convergent evolution)
- inherited from different ancestors that are often in similar environments
- if we fail to realize that states are analogous rather than homologous, this introduces error into phylogenetic reconstruction
54
How is molecular phylogenetics related to evolution?
- matching of bases in selected gene sequences
- mutations can cause changes in bases
- changes accumulate over evolutionary time
55
What is the significance of mutations in DNA?
It is the basis of variation that natural selection operates on
56
What is the relationship between DNA base pairs and the relation of a species to another?
More matches between species=more likely the species will be closely related
57
Convergent Evolution
The independent evolution of similar traits in different lineages eg: through mutation
58
Monophyletic
- Contains a common ancestor and all of its descendants and no other unrelated taxa (clade-its goal is to create monophyletic groups)
- monophyletic groups must use traits that are similar because of common ancestry
59
What is an ideal taxon?
-the goal is to organize species into groups with common ancestry that reflects ancestor-descendant relationships (only monophyletic taxa)
60
If structures have come from a common ancestor, why do they look different?
"descent with modification"
| -changes made with mutations, more desired structures are passed on in different environments, etc
61
Polyphyletic
- when taxa get lumped together even though they do not share recent ancestors
- are based on a common feature that does not exist evolutionarily eg: celebrity look-alikes (incorrectly grouped by superficial similarities-is not due to common ancestry)
62
What are the two possible characteristics of polyphyletic groups?
-more than one ancestor (possessing different ancestors)
OR
-lacking a common ancestor that unites members in a group
63
Give an example of a polyphyletic group
-including bats with birds because they would be incorrectly grouped by a similar characteristic (analogy)-is not due to common ancestry
64
Paraphyletic Group
- groups that do not contain all descendants of a common ancestor (forgetting about a branch that should be in the group-exclusion)
- usually make mistakes because some descendants appear different from other members of a clade
eg: Aves being excluded from class reptilia
