BIO UNIT 5 Flashcards
Evolution
The change of species over time
Evolution over time
-Organisms became more complicated
-Some organisms survived
-Some went extinct because they couldn’t adapt and change
Basic Theory of Biological Evolution
-Earth’s present day species developed from earlier, distinctly different species
How does evolution happen?
Gradual changes in organisms through time
Why did organisms evolve over time? (4 reasons)
- Potential increase in species amount
-Genetic variability from mutations + recombination of genes
-Finite resources
-Natural selection
What is individual change?
-Changes that occur during the lifetime of an organism
What is evolutionary change?
-Changes in the genes of an organism that causes changes in structure, function or behavior
-Mainly through mutations
Charles Bonnet’s Theory
-Hypothesized that major catastrophes occurred on earth
-Then new life began
-New life was better than the last life
WRONG!
Lamarck’s Theory
-Organisms strive to improve themselves
-Body structures that are used will develop, the unused waste away
-Structures inherited by offspring
August Weismann
-Proved Lamarck wrong
-Cut off tails of mice for 22 generations
-Always produced normal tails
Charles Darwin- 5 discoverings
-Geological forces are slow processes
-Not all offspring can survive because resources run out
-There must be competition between food, water, and space
-Winners survive and reproduce
-Parents with desirable characteristics raise desirable characteristics
5 Elements of natural selection
- There is variation within populations
- Some variations are favorable
- More young are produced in each generation that can survive
- Those that survive and reproduce are those with an adapted value/variation
- Over enormous spans of time, small changes accumulate and populations change
What was Charles Darwin’s theory called
Natural Selection
The environment causes change
-There is variation amongst individuals
Natural Selection leads to….
-Changing proportions of individuals with a certain trait amongst a population
What are examples of things that can evolve?
-Structures
-Functions
-Behaviors
What 4 pieces of evidence do we have for the Theory of Evolution?
- Fossil records of ancient life forms
- Molecular similarities
- Structural similarities
- Comparative Embryology (embryos of similar organisms develop in similar ways)
Vestigial structures
Inherited but unused structures
Homologous structures
-Characteristics inherited from common ancestors
Biological Species Definition
- An interbreeding population of organisms that can produce healthy and fertile offspring
Why is every organism its own species?
- They each have a NICHE- an organisms role in their environment
Biodiversity
Evolutionary processes lead to speciation, which ultimately creates a diversity of different life forms which create stability in ecosystem
What did Darwin propose could be a Model of Speciation?
-Artificial Selection
-Selective Breeding
What causes speciation?
-Natural selection
-Sexual selection
-Geographic isolation
What happens to those that do not evolve when faced with environmental change?
-EXTINCTION
Selective Breeding and Artificial Selection
-Artificial selection of qualities within an organism; then the breeding of that organism to pass those qualities onto the next generation
Binomial Nomenclature
-Two names for each organism:
Genus name and Species name
Rules of Binomial Nomenclature
- Genus name placed first and is capitalized
- Typed in italics, handwriting is underlined
- Genus name may be abbreviated with a single uppercase letter
Why not use simple common names?
-Common names vary from place to place
-False information
Taxon
-A category into which related organisms are placed
Taxonomy
-Field of biology that deals with classifying organisms
Traditional Classification
-Established by Carolus Linnaeus
-He believed all creatures created at once
-7 groups
Linnaeus System
-Based on structural similarities between organisms
-Latin based (descriptive native language)
What was Linnaeus’ system like?
-Based on a hierarchy: ranked categories from broadest to the most specific taxa
Modern Classification
- 3 Domain Classification system
3 domains
-Bacteria
-Archaea
-Eucarya
Dichotomous Key
-A tool used for identifying unfamiliar organisms
How does a Dichotomous Key work?
-Lists observable traits that eventually lead to the name of the organism
Phylogenetic Systematics/ Cladistics
-Recognizes groups of organisms that are related by common ancestor
Problems with traditional classifications
-Structural characteristics can give false impressions
-New techniques like molecular similarities aren’t accounted for
-Classification does not indicate common ancestors and evolution
Phylogenetic Tree
-Groups organisms together who share a common heritage based on shared ancestral characters
Branches, nodes, and tips
Branch= single group of organisms through time
Node= Point in the tree of a common ancestor; where branching occurs
-Tip = taxon (different groups)
Phylogenetic Trees are hypotheses….
-Scientists use structural features, molecular data, and behavioral traits to reconstruct evolutionary history
Natural selection
-Charles Darwin’s idea
- Organisms have variation, so there will be “winners” and “losers”
- Losers die and winners get to reproduce, which they over-do, and pass on their genetic variations to the next generation over a given amount of time
