Evolution Flashcards
What is evolution?
- the way species adapt to their surroundings
- the scientific theory that describes changes in species over time
- interactions with biotic and abiotic environmental factors
What causes evolution?
- environmental challenges (severe weather, famine, competition)
- organisms that survive and reproduce can pass their traits to their offspring
Adaptation
A structural, behavioural, or physiological process that helps an organism to survive and reproduce in a particular environment
Structural Adaptation
The physical features of an organism (camouflage)
Behavioural Adaptation
The actions of an organism (migration)
Physiological Adaptation
The bodily functions of an organism (hibernation)
Variations
- the differences between individuals of a population
- helpful variations cause the individual to survive longer, produce more offspring, and the characteristic becomes more common
Peppered Moths
- before Industrial Revolution, the majority of the population was light coloured
- helped them blend into the light forests
- after the IR, the forests turned dark so dark coloured moths had an increased chance of survival
- through natural selection, this trait became more prominent
Aristotle Era
Believed the earth and all living things could not change
Buffon
Believed that species had been created in a perfect form, but had changed over time
Erasmus Darwin
Believed that all life had evolved from a single original source
Larmarck
- use and disuse, body parts that were not used would disappear and body parts that were used would become larger and stronger
- inheritance of acquired characteristics, individuals pass on characteristics to their offspring that they gained in their lifetime
Cuvier
Discovered fossils and inferred that life had evolved from simple to complex organisms (catastrophism)
Lyell
Believed geological change is slow and gradual (uniformitarianism)
Malthus
Proposed that there was competition between species
Darwin
- developed the theory of natural selection
- change is slow and gradual
- organisms compete for resources
- variations are heritable
- some characteristics are more advantageous than others
Epigenetics
The study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself
Epigenome
A multitude of chemical compounds that tell a genome what to do and modify genes by turning them on or off
Fossils
- preserved remain or trace of a once living organism
- fossils that are younger and more complex are found closer to the Earth’s surface
- fossils that are older and simpler are found deeper in the ground
Biogeography
- the study of past and present geographical distribution of organisms
- geographically close environments are populated by similar species
- animals on islands have evolved from marine migrants
Homologous Structure
structure=same
function=different
-evolved from a common ancestor
Analogous Structure
structure=different
function=same
-no common ancestor
Vestigial Structure
- a structure that no longer serves a purpose
- it used to serve a purpose before the evolution of the organism
- body hair and wisdom teeth in humans
Embryology
- embryos of different organisms can show similar stages during embryonic development
- these similar features indicate a common ancestor
DNA
- carries genetic information
- you can compare DNA to determine the relationship between organisms
- the more similar the DNA patterns, the more closely related the organisms are
Individual
One organism within a population
Population
A group of individuals within a species
Species
All members of a population that can interbreed under natural conditions
Alleles/Traits
One or two alternative forms of a gene that arise by mutation and are found at the same place on a chromosome