MSCI345 Biodiversity and Classification

Biodiversity

the variety of organisms that live in a particular location or habitat.

ecosystem services

More diverse ecosystems are better at providing “ ” to humans; things provided by nature that we often take for granted but would be very hard-pressed to produce on our own if nature wasn’t doing it for us.

economy

More diverse ecosystems are better at supporting the global “ “.

new resources

More diverse ecosystems offer more opportunities to discover “ “

resilient

More diverse ecosystems are more “ “ to disturbance

diversity index

 a number that attempts to quantify diversity in some way.

Species Richness

(R) the number of species in a particular habitat, area, or biological community.

Evenness

refers to how even the proportions of each species are.

Gini-Simpson Diversity Index

When this diversity formula is applied to biodiversity, R represents the number of different species present in the community of interest (i.e., the richness), and pi represents the probability (on a scale from 0 to 1) of getting species “i” when you randomly pick an individual organism from that community. You can also think of pi as representing the proportion of the individuals made up by species i, because the probability is equal to the proportion.

Shannon-Wiener Diversity Index

a measure of how hard it is to predict what species you’ll get if you randomly select one individual out of an ecosystem or community in which you already know how many of each species are present.

1\.3 million

Over “ “ species on earth have already been described and assigned unique species names.

8 million and 10 million

Reasonable estimates put the total number of living species (including species that have not yet been discovered or named) at something between “ “ !

World Register of Marine Species

The largest, most comprehensive, international effort to catalog all marine life species; It currently lists over 240,000 known marine species.

taxon

simply a named group or category of organisms.

Scala Naturae

In this system, everything in the world, whether natural or supernatural, was arranged in a linear fashion with God at the very top and minerals at the very bottom.

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Do Kings Play Chess On Fine Green Silk?

binomial nomenclature

assigns to each species, living or extinct, a unique 2-part name

genus

refers to a taxonomic group containing a relatively small number of very similar species

specific epithet

identifies the species within the genus

capitalized

The first letter of every genus name is __always__ “ “ .

first letter of the genus

Only the “ “ name is capitalized; nothing else in the genus or specific epithet is ever capitalized, even if the specific epithet is based on a proper noun, such as a person’s name or a place.

italicized, underline

The entire scientific name should be “ “ . If you are hand-writing it or otherwise can’t italicize, then you should “ “ the name.

dissimilar

Genus names cannot be reused for “ “ taxa.

unique, reused

The specific epithet must be “ “ within a genus, but it may be “ “ for species in different genera (the plural of genus).

first letter, once

In publications, it is common to abbreviate scientific names by using only the “ “ of the genus name after the full scientific name has already been given at least “ “ prior to the abbreviation in that publication.

sp., spp.

When the genus is known, but the species isn’t known (or doesn’t matter), it’s common to use the genus name followed by the abbreviation “ ” or “ ”

Potential ways to define a species

* Nominalistic species concept


* Typological species concept
* Morphological species concept
* Biological species concept
* Phylogenetic species concept
* Recognition species concept
* Phenetic species concept
* Ecological species concept
* Genetic species concept

Phylogenetic tree

represent our best estimates as to how new species formed from this process of repeated speciation events, starting with that ancient ancestral cell and following all the splits and branches from way back then to the present day.

Cladistics

a particular approach to generating phylogenetic trees and classifying groups of organisms based on hypotheses about their evolutionary history.

cladogram

a particular type representing the hypothesized evolutionary relationships among some groups of organisms.

testable

Like other hypotheses, cladograms are designed to be “ '“.

how long ago

Cladograms attempt to describe which taxa are most closely related, but they do not attempt to represent “ “ groups diverged.

Monophyletic

describes a taxonomic group that includes an ancestral form and ALL of its descendants and nothing else

Clade

Same thing as a monophyletic group. Birds are a “ “

Cladogenesis

the formation of a new clade through speciation.

Polyphyletic

describes a taxon that fails to include the most recent common ancestor of the group’s other members.

Paraphyletic

describes a taxon that does include the most recent common ancestor of all the organisms in the group, but is missing one or more descendants of that common ancestor.

Synapomorphy

a shared, derived, characteristic that unites a clade. It’s a feature that first appeared in the most recent common ancestor of a group, then got passed down to the other members of the group.

Convergent evolution

Sometimes characters that are shared between two species but were NOT present in the common ancestor can mislead a scientist into thinking that two species are more closely related than they actually are.

Secondary loss of synapomorphies

loss of characters that otherwise unite a group.

Sessile Organisms

organisms that live attached to rocks or other (usually) stationary objects, so they can’t move from one place to another

Motile Organisms

These are organisms that can move around; the opposite of sessile.

Plankton

aquatic or marine organisms that cannot outswim typical water currents in areas where they live. They are therefore at the mercy of those currents, and get swept along wherever the currents take them.

Nekton

aquatic or marine animals that can outswim typical current speeds; are free to go more-or-less wherever they want, regardless of which direction the currents are flowing.

Pleuston

organisms living right at the air-water interface on the surface of a water body.

Benthos

Organisms that live on the bottom of the ocean

Benthic organisms

organisms that live on the bottom of the ocean; they are part of the benthos.

Demersal Organisms

These are motile organisms that live in close association with the bottom of the ocean (or another water body), but are not in direct contact with the bottom all the time.

Pelagic Organisms

These organisms live most or all of their life in the open ocean far from land. They may live mostly above the ocean surface (e.g., albatrosses and some other marine birds), on the ocean surface, or below the ocean surface, but they are not closely associated with land or the seafloor.

Autotroph

organisms derive their energy from sunlight or inorganic chemicals. They are also known as Primary Producers.

Photoautotrophs

organisms are autotrophs that derive their energy from sunlight through photosynthesis.

Chemoautotrophs

These organisms derive their energy directly from chemical reactions involving inorganic chemicals, such as hydrogen sulfide.

Heterotroph

organisms that get their energy by eating other organisms.

Herbivores

animals that eat plants, algae, or other non-animal organisms for food.

Predators

eat living prey. The term usually is limited to animals that eat other animals, but some people consider herbivores to be a subset of this group.

Scavengers

feed on the remains of dead organisms

Parasites

feed on the tissues or body fluids of other living organisms in a way that does not kill the host quickly.

Detritivores

feed on detritus, which is a general term for little bits of scrap organic matter, such as tiny bits of poop, plant fiber, or mucus, that originally came from other organisms.

Suspension feeders

feed on food particles (including whole organisms) suspended in the water column

Filter feeders

a subset of suspension feeders that capture suspended particles by passing water through a mesh or screen that traps any particles that are too large to fit through the holes in the mesh or screen.

Deposit feeders

feed on organic material that has settled onto surfaces or is buried in sediment.