Week 28 Flashcards
Define and describe the term biodiversity
Biodiversity consists of “bio” (life) and “diversity” (range of form and function). It represents the variety of life forms and their functions in an ecosystem.
Define and describe scales of biological organization
Life exists and interacts at multiple scales, including:
Atom
Molecule
Cell
Tissue
Organ
Organ system
Organism
Population
Community
Ecosystem
Define and describe four different types of biodiversity
Genetic Diversity : Genetic variation is a measure of the genetic differences that exist within a population. The genetic variation of an entire
species is often called genetic diversity.
Species diversity : Species diversity is a combination of two
measures:
1. The number of species in a given area. This is
called species richness. We call it N (N = number)
2. The abundance of each species in a given area.
Abundance is measured relative to the other
species, so this is called the relative abundance
of species.
3. Diversity can be calculated mathematically in
different ways, but always combines the two
such that each are taken into account.
Functional diversity : Functional diversity is a measure of biodiversity that generally
concerns the range of things that organisms do in communities and ecosystems. Functions keep an ecosystem running!
Ecosystem diversity : : Variation in ecosystems, including different community structures and environmental conditions.
Identify the scale at which different types of biodiversity exist
Genetic Diversity exists at the species and population levels.
Species Diversity is measured at the community level.
Functional Diversity occurs at the community and ecosystem levels.
Ecosystem Diversity is observed at the biome and biosphere levels.
Explain why different types of biodiversity are important to consider
Genetic Diversity ensures adaptability and resilience to environmental changes.
Species Diversity maintains ecosystem stability and interactions.
Functional Diversity supports essential ecosystem processes (e.g., nutrient cycling, pollination).
Ecosystem Diversity provides a range of habitats and conditions for various species to thrive.
Define species richness and species diversity
Species richness: the number (N) of species in the community.
Species diversity: incorporates both species richness and the evenness of species’ abundances.
Define evenness
biodiversity
the variation in the abundance of individuals per species within a community.
Define abundance and relative abundance
Abundance: the amount of each
species in the community. (e.g, # of individuals)
Relative abundance: The abundance of a species (by any measure), divided by the total abundance of all species combined.
Name the 2 modes of speciation
Allopatric speciation is initiated by a geographic barrier between individuals from two natural
populations.
Sympatric speciation takes place in a single geographic area.
What kind of **generation time **will organisms that have a more rapid evolution have ?
rapid generation time
distinguish between r vs k selection
- r = “reproductive” organisms
- Short-lived
- Few reproductive events
- Many offspring
- Low parental care
- Respond quickly to natural selection
- k = “carrying capacity” organisms
- Long-lived
- Several reproductive events
- Few offspring per event
- High parental care
- Tolerate and ‘adapt’ to change over
the lifetime of the organism.
Can speciation only be observed over millions of years ?
no
Discuss the reasons why the concept of a species is important.
- to categorize and identify organisms;
- to understand the evolutionary processes that
give rise to species.
Explain the morphological species concept (MSC).
- Species are defined based on their appearance and behavioural patterns.
- Can you really define a species based on appearance alone?
Identify cases in which the MSC is useful vs. when it is not.
Useful when: Studying fossils or species with clear physical differences.
Not useful when: There is phenotypic plasticity (variation due to environment rather than genetics) or cryptic species (species that look identical but are genetically distinct).
Define the biological species concept (BSC).
Species are defined by those populations which can interbreed; they are reproductively isolated from other groups.
Example: Happy Face Spiders (Theridion grallator) look different but are the same species because they can interbreed.
Define evolutionary species concept
- Species are defined by ancestry and evolutionary trajectory. This includes genetic isolation and uniqueness.
Compare and contrast prezygotic with postzygotic reproductive isolation mechanisms, and identify examples.
Prezygotic Isolation
* Processes that prevent two organisms from creating a zygote (no fertilization)
Temporal isolation: Species breed at different times.
Behavioral isolation: Different mating behaviors (e.g., meadowlark bird songs).
Postzygotic Isolation
* Fertilization occurs, but the zygote or offspring cannot survive or reproduce.
Example: Horses and donkeys can produce mules, but mules are infertile.
Identify at least two issues with the BSC.
Issue 1: Hybridization occurs between some species, making reproductive isolation unclear (e.g., Rainbow Trout and Cutthroat Trout interbreeding to form “Cutbows”).
Issue 2: Geographic separation can make it difficult to determine whether two populations could interbreed (e.g., frogs separated by a highway).
Explain how the ESC can be applied to differentiate between evolutionarily distinct groups.
The ESC uses genetic data (nuclear or mitochondrial DNA) to identify distinct lineages.
Example: Ensatina salamanders have different genetic clusters, which ESC uses to define species.
Hybridization
The process of producing offspring by mating two parents from different varieties or
species.
Name all the different types of biodiversity small to large
We can measure four different types of biodiversity. Small to large….
1. Genetic diversity
2. Species diversity
3. Functional diversity
4. Ecosystem diversity
Why might genetic variation within populations be low ?
- Migration, Isolation & Inbreeding (islands!)
- Natural Selection – different habitats require different
traits, so different phenotypes succeed under different
conditions. - Random chance! Genetic drift. Small populations retain
less diversity due to chance mating and death
Based on what you know about speciation, what
factor would allow you to better predict how long it
would take for speciation to occur?
A. Time passed
B. Generations produced per
unit of time
C. Number of offspring
produced per unit of time
D. Age of sexual maturity
B. Generations produced per unit of time
This is because speciation is more dependent on the number of generations that pass rather than just the absolute time that has elapsed. Faster generation turnover provides more opportunities for genetic variation, natural selection, and mutations to accumulate, which can drive populations to diverge into separate species over time.
r vs k selection
- r = “reproductive” organisms
- Short-lived
- Few reproductive events
- Many offspring
- Low parental care
- Respond quickly to natural selection
- k = “carrying capacity” organisms
- Long-lived
- Several reproductive events
- Few offspring per event
- High parental care
- Tolerate and ‘adapt’ to change over
the lifetime of the organism.
