BIOL 103 Module 4 Flashcards
what is sexual selection?
A type of natural selection where individuals with traits that increase their chances of mating are more likely to pass those traits to the next generation.
What are the main costs of sexual reproduction?
Costs include finding mates, fighting for mates, achieving fertilization (especially in sedentary species), and exposure to sexually transmitted diseases (STDs).
What is the “two-fold cost of sex”?
The idea that sexual populations have a reproductive disadvantage because only females contribute to the next generation, while males are not directly involved in producing offspring.
What is recombination’s role in reducing mutation load?
Recombination helps remove harmful mutations from a population by reshuffling genetic material, which allows for selection to act against harmful mutations and preserve beneficial ones.
What is the Red Queen hypothesis?
The idea that sexual reproduction helps organisms evolve in response to constantly changing environmental pressures, such as diseases and predators, ensuring that they do not get “outpaced” by their enemies.
How does sexual selection contribute to the evolution of traits like peacock tails?
Sexual selection can favor traits that make an individual more attractive to mates, even if those traits are costly to survival, like the large and colorful tail of the peacock.
What are the four main advantages of sexual reproduction suggested by scientists?
Reducing mutation load, escaping background of origin, bet-hedging, and the
What is inclusive fitness in the context of altruism?
The concept that an organism can increase its genetic success by helping relatives survive and reproduce, as they share a portion of the same genes.
What does Hamilton’s Rule state?
Hamilton’s Rule, “Br > C” or “r > C/B,” says that an individual will act altruistically if the benefit to the recipient (B) multiplied by the relatedness (r) is greater than the cost to the actor (C).
What is the difference between cooperation, altruism, selfishness, and spite?
Cooperation: Both parties benefit.
Altruism: One sacrifices their fitness for the benefit of others.
Selfishness: One benefits at the expense of others.
Spite: Both parties suffer a fitness loss.
How do coefficients of relatedness (r) work in Hamilton’s Rule?
The coefficient of relatedness (r) reflects the genetic relatedness between individuals. For example, r = 0.5 between parent and offspring, r = 0.25 between grandparent and offspring, and r = 0.125 between cousins.
What is the paradox of altruism?
Altruistic behavior, where an individual sacrifices their fitness for others, seems to contradict Darwin’s theory of natural selection, which favors behaviors that increase individual fitness. However, altruism can be explained by inclusive fitness and kin selection.
What are the four main types of species interactions?
Competition: Both species suffer (-/-).
Predation/Parasitism: One species benefits, and the other is harmed (+/-).
Mutualism: Both species benefit (+/+).
Commensalism: One species benefits, and the other is unaffected (+/na).
What is Gause’s Law (Competitive Exclusion Principle)?
It states that two species competing for the same resources cannot coexist in the same ecological niche. One species will always outcompete the other.
What is an example of competition in nature?
The interaction between lynx and coyotes, where both species suffer due to the competition for similar resources.
What is the difference between mutualism and commensalism?
Mutualism: Both species benefit (+/+).
Commensalism: One species benefits, and the other is unaffected (+/na).
What is an example of a mutualistic relationship in nature?
The relationship between plants and pollinators, where plants benefit from pollination, and pollinators benefit from food resources
How do species in competitive relationships interact in an ecosystem?
Species compete for limited resources, such as food, shelter, or mates, leading to negative impacts on both species involved (-/-).
What is the importance of species diversity in ecosystems?
High species diversity in ecosystems promotes stability, resilience, and the ability to respond to environmental changes, reducing the likelihood of invasive species successfully establishing themselves.
What is Shannon diversity (H)?
A measure of species diversity that combines species richness (number of species) and species evenness (how evenly individuals are distributed across those species). Higher H values indicate higher diversity.
What are some factors that limit the length of food chains?
- Energetic inefficiency of energy transfer between trophic levels.
- Instability: Food chains become less stable with each additional trophic level, making them shorter.
What is the role of dominant species in ecosystems?
Dominant species have a large impact on the structure and function of ecosystems. Their presence or absence can significantly affect community composition and ecosystem processes.
What is the difference between energy flow and chemical cycling in ecosystems?
A:
Energy flow refers to the movement of energy through an ecosystem, primarily from the sun to producers and through consumers, eventually being lost as heat.
Chemical cycling refers to the cycling of nutrients and elements (like carbon, nitrogen, and phosphorus) through biotic and abiotic components of the ecosystem.
What are the main drivers of ecosystem changes in biodiversity?
Human activities, including habitat destruction, pollution, and climate change, contribute significantly to the loss of biodiversity, with impacts on species interactions and ecosystem functioning.
