Chapter 4 - Evolution Flashcards
Fossil Record
Organizing fossils by age. Shows gradual change in organisms.
Homologies
Different organisms have similarities in body structures, DNA sequences, and development.
Biogeography
Similar but unique organisms exist in similar environments around the world.
Common Ancestry
The theory that related organisms evolved from a shared ancestor.
Cladogram
Diagram that used shared characteristics to show how organisms are related.
Natural Selection
Organisms possessing certain genotypic characteristics that make them better adjusted to an environment tend to survive, reproduce, increase in number or frequency, and therefore, are able to transmit and perpetuate their essential genotypic qualities to succeeding generations
Artificial Selection
The breeding of plants and animals to produce desirable traits.
Variation in Traits
Slight differences within the same species. E.g. Moth - Dark/Light wings.
Differential Survivability
One version of the trait must provide a greater chance of survival.
Adaptation Pressure Examples
Cactus - Sharp Spines - Improves survivability by providing protection against being eaten.
Cheetah - Fast - Improves survivability by increasing successful hunting.
Birds - Elaborate/Colourful Plumage in Males - Increases desirability to be a mating partner.
Selection Pressure Examples
Limited Sources - Food Supply, Clean Water, Living Space, Suitable Mates - In an environment where food is scarce throughout winter and animal may develop the adaptation of hibernation.
Environmental Threats - Predators, Human Activity, Disease - In an environment where predators hunt by sight, a species may develop the adaptation of camouflage.
Speciation
When a new species evolves from an existing species. E.g. Galapagos Finches.
