Speciation and Classification Where do all these different organisms come from and how are they described?

Speciation and Classification

Where do all these different organisms come from and how are

they described?

Speciation

• Change in allele frequencies in a population

• Occurs due to one of these:– Natural Selection– Sexual Selection– Drift in Small Population– Mutation

Natural Selection

• Individuals with undesirable traits are killed and produce fewer offspring

• Individuals with desirable traits survive and produce more offspring

Bacterial Resistance

Peppered Moth

Give an example for Natural Selection:

Natural Selection – When dumb people eat Hot Cheetos, they destroy their bodies and are more likely to die.

Sexual Selection

• Some individuals produce more offspring (greater opportunity to mate) so the frequency of those genes increases

– Traits may indicate healthy individuals– Traits may not serve any purpose at all

Great Frigatebird Bower Bird

BlondesAustralian Fur Seal

College Grad vs. Drop-Out• In general, the more

education humans have, the fewer offspring they tend to have…

• Which has greater fitness for natural selection?

• Which has greater fitness for sexual selection?

Give an example for Sexual Selection:

Sexual Selection – Finches think that blue leg bracelets are sexy, but not red ones.

Drift in Small Breeding Populations

• Founder Effect– Alleles from a small “founding” population are amplified

through interbreeding

• Genetic Drift– The allele frequencies in a small isolated population slowly

become different from the others

• Specializing (filling a niche)– Variation of individuals allows them to use the ecosystem

differently– Over time, breeding groups separate and traits become

amplified

Galapagos Finches (Specializing)

Aquatic Iguana (Genetic Drift)

Polydactyl Humans

(Founder)

Mutation

• New genes are introduced into a population– May be harmful, neutral or beneficial (rare)

Sickle Cell (harmful – carry oxygen less well)

Sickle Cell (beneficial – unaffected by malaria)

Albinism (neutral – marginally higher chance of sun damage)

Give an example for Drift or Mutation:

Drift – Squirrels on the top of Mt. Graham that could only breed with other squirrels on the mountain top ended up with more genes with red fur.

Mutation – Eating Hot Cheetos when pregnant causes the baby to develop weird birth defects.

Classification

• The way humans categorize organisms

• As we learn more we try to modify our classification to match genetic similarity

Cut out eight organisms.Lump them into three categories.Glue the pictures down and label each category.

does not have eyes

can’t fly

not good for snuggling

Try to make your categories genetically similar.

Hierarchical Classification

• Kingdom

• Phylum or Division (for Plantae)

• Class

• Order

• Family

• Genus

• Species

More Specific

Naming a species: Genus species

• Only one organism per “name”• Same name worldwide• Punctuation:

– Capitalize genus– Lowercase species– Italics or underlined

After people: Various species…

• Rhea darwinii (flightless bird)

• Strigiphilus garylarsonii (wingless chewing lice)

Descriptive: Mosquito species names

• punctor

• tormentor

• vexans

• horrida

• perfidiosus

• abominator

• excrucians

Need both the genus & species

• Opuntia engelmanii (prickly pear)• Echinocereus engelmanii (hedgehog cactus)• Opuntia bigelovii (teddy bear cholla)

Abbreviations• Opuntia engelmanii

• Opuntia spp. refers to any species in the genus Opuntia (flat segmented cactus)

• After it has been referred to once, the abbreviation O. engelmanii can be used

What differentiates species?

• Organisms with physical differences that cannot breed with one another

• Similar physiology and ability to have viable offspring defines a species

Issues in defining a species:

Location (how far away do they have to be?)

Physiology (how different do they have to look?)

Genetic incompatibility (what if the offspring are infertile?)

Define “species”

Deer mouse


Donkey

Horse

Mule



Hooded Crow Carrion Crow



Coyote mother + Grey wolf father = Red wolf



• Kingdom


• Class

• Order

• Family

• Genus

• Species

More Specific

Pneumonic Devices to Remember:

• Kissing Pretty Cathy On Friday Gives Satisfaction

Create an pneumonic device to help you remember the order for classification:

KP –or– DCOFGS


• Kingdom


• Class

• Order

• Family

• Genus

• Species

More Specific

Hierarchical Classification: Ex. 1• Kingdom: Animalia• Phylum: Chordata (nerve cord)

– Subphylum: Vertebrata (backbone)– Superclass: Tetrapoda (4-legs, land)

• Class: Mammalia (mammals)• Order: Carnivora (meat-eating)• Family: Felidae (cat-like)• Genus: Felis (small cats)• Species: rufus (Bobcat)

Hierarchical Classification: Ex. 2

• Kingdom: Animalia• Phylum: Chordata (nerve cord)

• Class: Mammalia (mammals)

• Order: Carnivora (meat-eating)

• Family: Felidae (cat-like)

• Genus: Felis (small cats)

• Species: rufus (Bobcat)

What would a Leopard have in common with

the Bobcat?

(In terms of classification)












• Genus: Panthera (large cats)

• Species: pardus (Leopard)








What would a Coyote have in common with

the Bobcat?












• Family: Canidae (dog-like)

• Genus: Canis (dogs)

• Species: latrans (Coyote)








What would a Rock Squirrel have in common with the

Bobcat?











• Order: Rodentia (rodents)

• Family: Sciuridae (active year-round, during the day)

• Genus: Spermophilus (“loves seeds”)

• Species: variegatus (rock squirrel)




• Order: Cetacea (fully aquatic)

• Family: Delphinidae (dolphin)

• Genus: Tursiops (debated…)

• Species: truncatus (bottlenose)

What would a Great White Shark have in

common with the Bottlenose Dolphin?


http://www.nationalgeographic.com/kids/creature_feature/0206/sharks2.html




• Order: Cetacea (fully aquatic)

• Family: Delphinidae (dolphin)

• Genus: Tursiops (debated…)

• Species: truncatus (bottlenose)


• Class: Chondrichthyes (cartilaginous fish )

• Order: Lamniformes (sharks)

• Family: Lamnidae (mackerel sharks)

• Genus: Carcharodon (white shark)

• Species: carcharias (great white)

Dichotomous Key

• Groups are always split into TWO until there is only one organism remaining

• Each line has a description

• There is only one organism at the end of each line

Phylogenetic Trees

• Groups are always split into TWO until there is only one organism remaining

• Every branch has a label

• There is only one organism at the end of each branch

Phylogenetic Tree

Phylogenetic Tree 1

plants animals

Phylogenetic Tree 1

plants animals

no backbonebackbone

Phylogenetic Tree 1

plants animals

no backbonebackbone

live birthlays eggs

Phylogenetic Tree 1

plants animals

no backbonebackbone

live birthlays eggs

aquatic

feathers

Phylogenetic Tree 1

plants animals

no backbonebackbone

live birthlays eggs

aquatic

feathers

carnivoreherbivore

flies

flightless

Dichotomous Key

Example:1a. Is a plant …………………………. Tree

1b. Is an animal ………………………. 2


1b. Is an animal ………………………. 2

2a. Has a backbone ………………. 3

2b. No backbone …………………. Bee


1b. Is an animal ………………………. 2



3a. Live birth …………………………. 4

3b. Lays eggs …………………………. 5


1b. Is an animal ………………………. 2



3a. Live birth …………………………. 4

3b. Lays eggs …………………………. 5

4a. Carnivore …………………….. Lion

4b. Herbivore ……………………. Horse


1b. Is an animal ………………………. 2



3a. Live birth …………………………. 4

3b. Lays eggs …………………………. 5



5a. Is aquatic …………………………. Frog

5b. Has feathers ………………………. 6


1b. Is an animal ………………………. 2



3a. Live birth …………………………. 4

3b. Lays eggs …………………………. 5



5a. Is aquatic …………………………. Frog

5b. Has feathers ………………………. 6

6a. Flies …………………………... Duck

6b. Flightless ……………………... Kiwi

Making your tree/key…

• It’s about HOW CLOSELY RELATED– To the best of your knowledge

• Overall traits becoming more specific

• Pick 8 organisms from the pictures

Documents

Speciation and Classification Where do all these different organisms come from and how are they described?