BIOL 305 - Lecture 3: Species

What is biological diversity?

consists of different “forms” of living things

What is species diversity?

a measure of all the various species within an area, community, or region

What can species diversity incorporate?

relative abundance among species (comparisons)

What does it mean when there is genetic diversity among species?

not all species are created the same/equal

tuatara

What does natural selection act on?

the individual

individual can survive, and if successful?

reproduce

individual can acclimate, but?

doesn’t adapt (in the same sense of evolution)

What is a population?

a group of individuals of the same species occupying a specific area and time

Individuals in a population have a high potential to?

interact with each other

Individuals in a population are?

All of the above

In the simplest sense, what are species?

the different kinds of organisms

individuals of the same species:

share genetic similarity and can potentially interbreed

A species has __________ range

geographic

A species is often compromised of what?

populations

What did taxonomy involve?

European age of exploration

Carolus Linnaeus 1707-1778

Binomial nomenclature

European age of exploration

18th-19th century, Europeans gained a global-scale view of the natural world, specimens around the world

Carolus Linnaeus (1707-1778)

developed binomial nomenclature; we needed a standardized, systematic scheme of taxonomy

What is binomial nomenclature/

classifies life by relatedness by a hierarchical organization of life based from most to least inclusive

What is taxonomy?

the science of naming and organizing life

Brown bear Taxonomy

D - Eukarya

K - Anamlia

P - Chordata (vertebrates; animals with a backbone)

C - Mammalia

O - Carnivora

F - Ursidae (family of bears)

G - Ursus

S - Ursus arctos

How does Brown bear taxonomy differ from Black Bear?

at the species level - Ursus americanus

How does Polar bear taxonomy differ from Brown/Black bear?

at the species level - Ursus maritimus

Wolf Taxonomy

D - Eukarya

K - Anamlia

P - Chordata (vertebrates; animals with a backbone)

C - Mammalia

O - Carnivora

F - Canidae (family of dogs)

G - Canis

S - Canis lupus

Human Taxonomy

D - Eukarya

K - Anamlia

P - Chordata (vertebrates; animals with a backbone)

C - Mammalia

O - Primates

F - Hominidae (Great apes)

G - Homo

S - Homo sapien

What does Homo sapien mean?

wise man

What does homology possess?

characters (traits) shared from common ancestors, separation via region

What is the morphological species concept?

a group of individuals that is morphologically (form/structure) or physiologically distinct from other groups in some important characteristic

What is the biological species concept?

species are groups of actually or potentially interbreeding populations which are reproductively isolated from other such groups (Ernst Mayr 1940)

What does the biological species concept depend on?

reproductive isolation

What does the fact that polar bears and brown bears can reproduce viable offspring prove?

they’re the same species

Species as evolutionary lines of descent is described by

On the Origin of Species, Charles Darwin 1859

Species have a history based on observations

originate along lines of descent from ancestral species

survive for varying periods, during which they may produce new species (speciation) before going extinct

All species go extinct, what’s left is:

descendants

Species are usually composed of groups of populations each having spatial and temporal cohesion

maintained by genetic and ecological mechanism

What does the cohesion perspective define?

a species as an evolving entity with a definitive:

• beginning or end

• place or origin and final refuge

Species are evolving units

sexual species show genetic reticulation

What is genetic reticulation?

pattern of genetic exchange often every generation

What is speciation?

process where two or more species evolve from a single ancestral population

What does speciation represent?

a process of splitting (cladogenesis) in the reticulation of the ancestral species

What do species derive?

other species

Alfred Russel Wallace

formed the theory of evolution

What did Alfred Russel Wallace claim?

'every species has come into existence coincident both in time and space with a pre-existing closely allied species’

What does speciation involves?

transition from a reticulate network of genetic exchange to different independent lineages,

each daughter species gains its own evolutionary trajectory, niche, and geographic structure,

but speciation might not be clean

What is the evolutionary species concept?

an entity, composed of organisms, that maintains its (genetic) identity from other such entities through time and over space, and that has its own independent evolutionary fate and history

What is a reticulated species?

derived from two previous species; species merge/hybridize, creating overlapping lineages

What are reticulated species most common in?

flowering plants, but are also common in animals

What is an example of reticulated species?

Woodhouse’s and Arizona toads - hybridization

• Woodhouse's toads bred Arizona toads out of existence

What is the scientific name for Woodhouse’s toads

Bufo woodhousii

What is the scientific name for Arizona toads

Bufo microscaphus

Which of the following are species concepts?

All of the above

What does the evolutionary species concept takes a long time for?

speciation; separate evolutionary lineages

Some well-differentiated populations probably do not warrant recognition as a distinct species, resulting in:

taxonomic units below the species level

What are taxonomic units below the species level, as defined by Lomolino et al. 2017?

Varity

Ecotype

Phylogroup

Evolutionary significant unit (Craig Moritz)

Subspecies

Distinct population segment

What is Varity?

used by plant taxonomists/botanists

What is Ecotype?

specialize on a particular ecosystem; used by mostly ecologists

What is a Phylogroup?

identified by genetic patterns; used by phylogeographers

What is a Evolutionary significant unit (Craig Moritz)?

differentiated by a morphological (DNA)/physiological criteria

What is a Subspecies?

group of populations geographically distinct with unique traits but can still interbreed; used by animal taxonomists/biologists

What is a Distinct population segment?

a vertebrate population (mammal, bird, reptile, amphibian, fish) or group of populations that is discrete from other populations of the species and significant in relation to the entire species

What defined a distinct population segment?

the U.S. Endangered Species Act of 1973

How is a distinct population segment described, geographically or biologically?

geographically

What can protections under the ESA can be applied to?

a populations(s) in a particular area rather than a species