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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