Chapter 22: Darwin View of Life Flashcards
Describe Evolution
- Darwin’s def: descent with modification (all organisms are related from descent from an ancestor)
- Can be viewed as a pattern & process
- The development of living organisms from earlier forms on Earth
What is Convergent Evolution
- Organisms are not related but develop same adaptations
- Can’t provide info about ancestry
What was the influence of fossils in Darwin’s study?
- Fossils helped lay the groundwork for Darwin’s ideas
- Fossils: traces of organismims from th past
- Appear in layers called strata
- Top stratum have more recent fossils in relation to bottom stratum
- Palentology: study of fossils
What was Lamarck’s hypothesis for Evolution?
- Hypothesis: species evolve via use/disuse of body parts and inheritance of acquired characterstics
- Not supported by evidence
What were some of Darwin’s obsrvations and inferences?
- Collected specimens during his travels on the Beagle
- Observed resemblance of fossils in same & different regions
- Via observations, perceived adaptation to the enviornment and origin of new species as closely related processes
- Wrote an essay on natural selection as mechanism of descent with modification
What is Natural Selection?
Process where individuals with favorable inherited traits are more likely to survive and reproduce
What were Darwin’s three broad and main observations?
- Unity of life
- Diversity of life
- Organismis suited to life in their environment
What is artifical selection?
- Modifcation of other species
- Through selecting and breeding individual w/ desired traits
What were the 5 key observations in Darwin’s Theory of Evolution
- Populations produce more offspring then there are adults
- Populations do not continue to grow in size
- Food/resources are limited
- Individals vary within population
- Many variations are heritable
What were the 2 key inferences in Darwin’s Theory of Evolution?
- Individuals within a population compete for resources
- Some individuals might inherit better characteristics that give them a higher chance of surviving (equal inability will lead to accumulation of favorable traits)
Whatis Darwin’s Theory of Natural Selection
- Population changes over time
- Advantageous heritable characteristics keep on becoming more common generation after generation
What are some key features of Natural Selection?
- Certain heritable traits helps individuals survive and reproduce better
- Natural selection increases frequency of adaptation in an environment
- Natural selection can give rise to new species
- Populations evolve! NOT INDIVIDUALS
- Natural selection increase/decrease hertiable traits that vary in a population
- Selects/edits for traits not create new ones
What is the difference between Darwin’s and Lamarc’s Theory?
- Darwin: changes occur by chance at birth & supports survival of the fittest (ex: amputee mom not equal to amputee child)
- Lamarc: changes occur through the organism’s lifestyle & doesn’t support survival of the fittest
(ex: amputee mom = amputee child)
What is fitness?
Ability to survive and breed to pass on genes
What are the four types of data that document the pattern of evolution?
- Direct observations
- Homology
- Fossil record - document important transitions
- Biogeography - scientific study of geographic distribution of species
