Chapter 4 - Unit 2 Flashcards
What is variation
A visible or invisible difference that helps an individual or population to survive
What is evolution
Evolution is the process of change in the genetic traits of a population over generations through mechanisms like natural selection, mutation, gene flow, and genetic drift.
There are 8 types of evolution:
1. Microevolution
2. Speciation
3. Microbial evolution
4. Macroevolution
5. Chemical Evolution
6. Coevolution
7. Divergent Evolution
8. Convergent Evolution
What is Embryology?
Closely related organisms go through similar stages in their embryonic development
What is Transformation
New species may result from accumulated changes in the population over a long period of time. A new species gradually develops as a result of mutation and adaption to changing environmental conditions, and the old species is gradually replaced
What is Divergence
One or more species arises from one parent which continues to exist
What is the difference between divergence and transformation
- Transformation happens over a long period of time (original species forms into another species)
- Divergence happens over a shorter period of time, and the original species splits into alternate species, which is caused by isolation
Pace of Evolution Comparisons
- Gradualism - slow, steady, linear change over time
- Punctuated equilibrium - long periods of equilibrium interrupted by periods of speciation
Macro vs. Micro Evolution
Micro evolution: Variation within a species (within the same species)
Macro evolution: Major groups evolving into entirely new creatures
Adaptation
Adaptation is a physical feature, behaviour, or physiological process that helps an organism survive and reproduce in a particular environment
Physical Adaptations
- Structural Differences
- Examples: sharps, talons, large ears for heat loss, webbed feet
Behavioral Adaptations
- Differences in how an organism acts
- Examples: Hibernation, migration, being nocturnal, courtship behaviors
Physiological Process
- Refers to the inner workings of an organism
- Examples: Production of venom, blood clotting, mechanism, antifreeze proteins in fish
What is selective pressure
- Selective pressure is an environmental factor or influence that affects an organism’s ability to survive and reproduce, driving natural selection by favoring certain traits over others. Organisms with beneficial traits are more likely to survive and pass on their genes, while those with less advantageous traits may struggle to reproduce or survive.
- Example:In a population of moths, if the environment becomes polluted and tree bark darkens due to soot, darker-colored moths (which are better camouflaged) are less likely to be seen and eaten by predators. Over time, this selective pressure favors dark-colored moths, leading to an increase in their population while lighter-colored moths become less common.
Homologous vs. Analogous Structures
Homologous: Structures have similar structural elements and origin but may have a different function
Analogous: Structures perform similar functions, even though the organisms do not have a common evolutionary origin
What is a mutation
Changes in the genetic material (DNA) of an organism
What is a fossil record?
Fossils that are found in different layers of the earth. These give us the following evidence:
1. Fossils in younger rock are similar to today’s species
2. Fossils are in chronological order (older laters have older fossils)
3. Not all organisms are found in the fossil record at the same time
Isolation/barriers
Keeping populations separate
- Geographical Barriers: Physically separates species from interbreeding (ex. Mountains, rivers, lava flows)
- Biological Barriers: Prevent populations from interbreeding (Bird calls, frog mating calls, or pheromones
- Reproductive Isolation: Cichlids in lake Victoria
Lamarckian Evolution
Species changed over time based on use or disuse of a feature. This theory believed that characteristics acquired through an organism’s lifetime would be passed onto the next generation (inheritance of acquired characteristics)
Natural Selection
The process by which a population of organisms changes because individuals with certain traits can better survive the local environmental conditions (selection pressures) and pass on these traits to their offspring. A wide variety of traits and selective pressure are required for natural selection to occur
Biogeography
The study of the geographical distribution of organisms, provides information about how and when species may have evolved
- Geographically close environments are most likely to contain related organisms
- Animals on islands are similar to animals on the closest continent
- Fossils of similar species are found on coastlines of neighbouring continents
- Closely related species are almost never found in exactly the same location habitat
Molecular Genetics
Molecular genetics is the study of DNA, genes, and heredity at a molecular level.
- DNA Sequencing 🧬
Definition: Comparing the DNA of different species to find genetic similarities.
Example: Humans and chimpanzees share about 98-99% of their DNA, indicating a close evolutionary relationship.
2.Homologous Genes & Proteins 🏗️
Definition: Genes and proteins that are similar across different species due to shared ancestry.
Example: The Hox genes, which control body plan development, are found in many animals, from fruit flies to humans.
3.Mutations & Genetic Variation 🌱
Definition: Mutations in DNA create genetic differences that drive evolution over generations.
Example: Mutations in antibiotic-resistant bacteria demonstrate microevolution in action.
Speciation
Long-term microevolution due to population isolation
