Speciation and Classification

Species- a group of organisms capable of interbreeding and producing fertile offspring

Forming a new species ◦ Each population of a single species lives in a

different place.

◦ In each place, natural selection acts on the population and tends to result in offspring that are better adapted to the environment.

◦ If the environments differ, the adaptations may differ.

◦ As the populations of the SAME species differ, divergence occurs, can lead to the formation of a new species.

Occurs when the effects of evolutionary forces result in a population that has unique features and is reproductively isolated.

Reproductive Isolation: Two populations can no longer interbreed. ◦ Geographic Isolation: a population becomes

specialized for a specific environment

◦ Habitat Isolation: Living in the same general area, but having different habitats

◦ Temporal Isolation: Reproducing at different times

◦ Behavioral Isolation: Courtship patterns change so as to attract different mates

Extinction occurs when a species fails to produce any more descendants.

Extinction is as much a part of evolution as speciation is.

99% of all species that have ever lived on Earth have become extinct.

Usually, extinction happens for the reason that Darwin proposed.

Species compete for resources, and the environments change. Some species adapt and survive, while others gradually become extinct.

Several times in Earth’s history, mass extinctions wiped out entire ecosystems.

A. Temporal Isolation

B. Geographic Isolation

C. Behavioral Isolation

D. Habitat Isolation

A. Temporal Isolation

B. Geographic Isolation

C. Behavioral Isolation

D. Habitat Isolation

A diagram that is used to show relationships between organisms

A. K

B. F

C. D

D. G

A. C

B. H

C. J

D. B

A. They live in different areas

B. They look slightly different

C. Their diet primarily consists of different plants

D. They can no longer interbreed

A. Stabilizing selection

B. Disruptive selection

C. Directional selection

D. Abrupt selection

A. Stabilizing selection

B. Directional selection

C. Abrupt selection

D. Disruptive selection

A. Homologous structures

B. Vestigial structures

C. Analogous structures

D. Embryological structures

A. Homologous structures

B. Analogous structures

C. Fossil record

D. DNA comparison

A. True

B. False

Sympatric Speciation: ◦ The process by which new species evolve from a

single ancestral species while inhabiting the same geographic area.

◦ Thought to be rare in multicellular eukaryotic organisms

Occupy different NICHES within the same area

Behavior of one type of organism changes

Ploidy Change

Niche ◦ The position or function of an organism in a

community of plants and animals.

Ploidy ◦ The number of sets of chromosomes in a cell

◦ The haploid number for humans is 23, the diploid number for humans is 46.

Allopatric Speciation ◦ The process by which new species evolve from a

single ancestral species after isolation due to geographic interruption.

EXAMPLE: Squirrels in the Grand Canyon

Species have 2 types of names: ◦ Common name- This is the name by which you

most often hear an organism called (i.e. human, dog, etc.)

◦ Scientific name- This is the 2 word Latin name which scientists use to classify organisms (Homo sapiens, Canus lupus, etc.).

The reason scientists don’t use common names is because multiple common names exist for 1 organism.

Scientific names provide a standard by which all scientists can communicate.

shadbush, serviceberry, sarvisberry, juneberry, Saskatoon, shadblow, shadwood, sugarplum, and wild-plum

This can cause much confusion because not all people are familiar with every common name so scientists started using scientific names.

Scientific names cut down on confusion because every organism has only 1 scientific name.

Bacteria (prokaryotes) ◦ Eubacteria - unicellular

Archaea (prokaryotes) ◦ Archaebacteria – unicellular, tend to live in extreme

environments

Eukarya (eukaryotes) ◦ Protista – generally single-cellular

◦ Fungi – multicellular, have cell wall, heterotrophic, non-mobile

◦ Plantae – multicellular, have cell wall, autotrophic

◦ Animalia – multicellular, no cell wall, heterotrophic, mobile

A system to classify all plants and animals.

Kingdom, Phylum, Class, Order, Family, Genus, Species! ◦ King Philip Came Over From Germany Singing!

Human Example ◦ Kingdom: Animalia

◦ Phylum: Chordata

◦ Class: Mammalia

◦ Order: Primates

◦ Family: Hominidae

◦ Genus: Homo

◦ Species: sapiens

Homo sapiens

The first word in a scientific name is the genus to which an organism belongs. ◦ Humans belong to the genus “Homo”

The second word is the organism’s species. ◦ Humans belong to the species “sapiens”.

Notice the scientific name is always italicized, the genus name is capitalized and the species name is not. ◦ Amelanchier canadensis (binomial nomenclature)

◦ Scientists use dichotomous keys to help them figure out the name of organisms which have already been classified and named.

1. Is it green or does it have green parts? A. Yes - go to 2

B. No - go to 3

2. How many cells make up the organism? A. Single-celled? Protista.

B. Multicellular? Plantae.

3. How many cells make up the organism? A. Single-celled - go to 4

B. Multicellular - go to 5

4. Can you see any detail inside the cell? A. Yes - Protista.

B. No - Monera.

5. Is it moving? A. Yes - Animalia.

B. No - Fungus.

A. Class

B. Family

C. Kingdom

D. Order

A. Family

B. Genus

C. Kingdom

D. Phylum

A. They are genetically similar

B. They are the same species

C. They are in different genera

D. They are in different kingdoms

A. Squid and Octopus (same class)

B. Lobster and eel (same kingdom)

C. Chimpanzee and gorilla (same family)

D. Iguana and mouse (same phylum)

A. Give the beetle new genus and family names

B. Give the beetle a new species name not used in the genus Tenebrio

C. Name the beetle after the species it is most similar to.

D. Discard the beetle because it is not found in existing taxonomy.

A. Anamlia

B. Plantae

C. Fungi

D. Eubacteria

A. Bacteria

B. Plantae

C. Virus

D. Protista

A. Cell membrane

B. Chloroplast

C. Mitochondrion

D. Ribosome

A. Anamalia

B. Fungi

C. Protista

D. Plantae