A3 Adaptation and Evolution Review Flashcards
What is a habitat?
-Habitat is a place or area with a particular set of characteristics, both biotic and abiotic
-species may all live in the same habitat or not
What is range?
-The geographical area where the population or species is found
-limit is usually due to habitat restrictions
What is ecological niche?
-The role a species plays in a community
-what it eats, where it lives and how it interacts with other species
What is biodiversity?
-Variety of species
-can vary widely depending on the biotic and abiotic components
-diversity is good
What are factors that limit growth in ecosystems?
- Abiotic limiting factors: limit the distribution and size of the populations that live there (water, soil type)
- Biotic limiting factors: include competition, predators and parasites (interspecific is different, Intraspecific is same)
What is natural selection?
-Process that results when characteristics of a population of organisms change because individuals with certain inherited traits survive and reproduce
-variety in a population must exist
-populations change not individuals
What are selective pressures?
-Any reason for organisms with certain phenotypes (different observable characteristics: hair color, height) to have either a survival benefit or disadvantage
What is evolution?
-Changes to a species over time
-microevolution: change to trait frequency (small change/short time)
-macroevolution: larger changes to the organism (e.g. speciation: new species is formed)
What is Lamarck belief about evolution? (Wrong)
-Inheritance of acquired characteristics
-characteristics that an organism acquired during its lifetime could be passed on to their offspring
-e.g. giraffe’s long neck
How can Darwin’s theory of evolution by natural selection be divided?
- Overhead (to many babies)
- Competition (not all survive)
- Variation (all babies are different)
- Survival of the fittest (some differences are good)
- Speciation (the good ones get passed down)
Explain “overhead” in Darwin’s theory of evolution by natural selection
-Number of offspring produced by a species is greater than the number that can survive, reproduce and live to maturity
Explain “competition” in Darwin’s theory of evolution by natural selection
-(struggle for existence) organisms compete for limited resources such as food, water and a place to live
-competition exists between (interspecific competition) and within (Intraspecific competition) species
Explain “variation” in Darwin’s theory of evolution by natural selection
-Differences in traits among members of a species are passed on to the next generation
-no two individuals are exactly alike
Describe “survival of the fittest” in Darwin’s theory of evolution by natural selection
-(natural selection) species that have traits that give them an advantage are better able to compete, survive and reproduce
-this process naturally selects the organisms that survive
Describe “speciation” in Darwin’s theory of evolution by natural selection
-(origin of a new species) by the inheritance of successful variations: new species arise by the accumulation of inherited variations
-eventually a new type is produced that is so different from the original that it is a new species
What are fossil records?
-Fossils found in young layers of rock are much more similar to species alive today then fossils found in deeper, older layers of rock
-fossils appear in chronological order
-not all organisms appear in the fossil record at the same time
What are transitional fossils?
-Fossils that show intermediary links between groups of organisms
-e.g. Archaeopteryx showed characteristics of reptiles and birds
What is biogeography?
-Study of the past and present geographical distribution of organisms
-geographically close environments are more likely to be populated by related species than are locations that are geographically separate but environmentally similar
What is anatomy?
-Study of the structure of organisms and their parts
What’s are homologous structures?
-Those that have similar structural elements and origin but may have a different function (forelimbs of humans, frogs, bats, and dolphins)
What are analogous structures?
-Those that perform similar functions even though the organisms do not have a common evolutionary origin (wing of butterfly and bat)
What are vestigial structures?
-Body parts with function
-Must have served a role in some ancestor
What is embryology?
-Embryos of different organisms exhibit similar stages of embryonic development
What is molecular biology?
-If 2 species have similar patterns in portions of their DNA this similarity indicates that these portions of their DNA were most likely inherited from a common ancestory
-can also compare protein similarity
What is speciation?
-Formation of new species - the accumulation of small changes until new member can no longer produce with original members
1. Transformation: a new species gradually replaces an old species
2. Divergence: one or more new species arise from a parent species
What are the causes of speciation?
-Allopatric speciation
-sympatric speciation (more rare)
What is allopatric speciation?
-(Geographic isolation): occurs when populations of a species are separated by a physical barrier
What is sympatric speciation?
-Occurs without a physical barrier to mating
-mutation leading to chromosome number changes in plants
What is adaptive radiation?
-When a species spreads among isolated regions (e.g. islands) and then changes as a result of different pressures
