EVOLUTION & CLASSIFICATION

Evolution:

Evolution: change in species over timeSpecies ADAPT (or change) in order to increase chance of survival

Variation among species can occur due to…

Recombination of traits (mating)

Mutations in DNA sequence

Evidence for Evolution-

FossilsCompare them to each other or current organisms

(Chimp) (Peking Man) (Human)

Evidence for Evolution:

Anatomical StructuresHomologous: similar structures in various organisms

EX. Similar arm and hand bones in human, bat, bird, whale

Evidence for Evolution:

Anatomical StructuresVestigal: reduced in size and function

EX. Pelvic bones in whale; appendix in humans

Evidence for Evolution:

Anatomical StructuresAnalogous: similar structure, not same ancestor

EX. Wings of bird vs. wings of butterfly

Evidence of Evolution-

Embryology: similarities in fetal development

Mouse Embryo

Human Embryo

Evidence for Evolution-

Biochemistry / DNA: similarities in the chemical compounds that make up organisms / similar DNA patterns

Ex. 80% similar to Insects

Ex. 99% similar to Chimps

THEORY of EVOLUTION

Charles DarwinNaturalist who studied the diversity of organisms Developed the concept of NATURAL SELECTION

Born Feb. 12th, 1809

in England

Charles Darwin

1831-1836 Darwin served as a naturalist on the HMS Beagle

He studied plants, animals, and fossils from various locations in and around South America

Developed several theories- one of which was the Theory of Natural Selection (aka “Survival of the Fittest”)

Darwin & the Galapagos Islands

THEORY OF NATURAL SELECTION:

Variation within populations- natural differences among same species

Some variations are favorable- improve ability to function and reproduce

Not all young survive- killed by disease, predators; only some reproduce

Survivors are those with favorable traits- offspring inherit those traits/genes

Natural Selection - Galapagos

Types of Evolution:

Divergent Evolution- isolated species evolved independently

Ex. Polar Bear / Brown Bear

Types of Evolution:

Convergent Evolution- similar adaptations in response to similar environment

Ex. Big ears on desert creatures

Types of Evolution:

Co-Evolution- adaptations affected by interaction with other organisms

Ex. Pollinators and flowers

CLASSIFICATION:

Grouping of things according to similar characteristics

WHY?Show evolutionary relationships (phylogenetic tree)

Learn about the similarities/differences of items

Discover relationships between living and non-living things

Gives a unique name to each organism, etc.

TAXONOMY:

Biological classification system of naming and organizing organisms

Binomial Nomenclature –

“two-name system of naming” developed by Carolus Linneaus

(18th century Swedish scientist)

All living things are classified into…

Kingdom ex. Animalia (Broadest)

Phylum ex. Chordata

Class ex. Mammalia

Order ex. Primates

Family ex. Hominidae

Genus ex. Homo

Species ex. sapiens (Most specific)

How to name an organism…

Binomial nomenclature uses the Genus and the species of an organism to name it

Genus is capitalized

species is NOT capitalized

Both are underlined or italicized

Ex. Homo sapiens or Homo sapiens

Dichotomous Key:

AKA Taxonomic Key- a guide designed to identify organisms; uses pairs of observable traits to pinpoint the identity of an organism

Keys to creating a “KEY”…

Use constant characteristics (something it always has) rather than variable ones. Use measurements rather than terms like "large" and "small". Make the choice a positive one - something "is" instead of "is not". If possible, start both choices of a pair with the same word. Precede the descriptive terms with the name of the part to which they apply.

Example-

1. a. wings covered by an exoskeleton …go to step 2b. wings not covered by an exoskeleton …go to step 3

2. a. body has a round shape ……ladybugb. body has an elongated shape ……grasshopper

3. a. wings point out from the side of the body …dragonflyb. wings point to the posterior of the body …housefly