lesson 12 Flashcards
(46 cards)
Behavioral Isolation
Males perform species-specific courtship ritual recognized by females that belong to the same species.
Hybrid breakdown
Hybrid (F1) is viable and not sterile, but progeny of hybrid (F2) and subsequent generations (F3, F4, F5, etc.) have lower fitness.
Reduced hybrid viability/fertility
Hybrid o!spring develops successfully, but usually unfit, dies before reproductive age, or is sterile.
Possible to create a humanzee?
no
Issues with Biological Species Concept
- Reproductive isolation may not be the only force maintaining species integrity.
- Interspecific hybridization.
- 50% of California plant species, in one study, not well defined by genetic isolation.
- 10% of world’s 10,000+ bird species known to hybridize in nature.
- Difficult to apply the concept to populations that are geographically separated in nature
- Many species that do not hybridize in the wild will do so in captivity
- Many organisms are asexual
- Possible that different processes maintain species identity in di!erent organisms
Ecological species concept
- Each species adapted to its environment
- Distinctions among species are maintained by natural selection.
- Stabilizing selection maintains the species’ adaptations.
- Hybrids are quickly eliminated from gene pool.
- In some cases, strong selection overwhelms gene flow.
Lisa of things that can go wrong during reproduction
- in fertilization
- gametic isolation: games are not compatible
- reduce hybrid viability
mechanical isolation
- Imcomplatible reproductive organs
- members of the same species
each specie is adopted to……
its own enviroment
punctuated equilibrium
fossil record- equilibrium is broken
if change gradually
expects gradually
- Evolutionary theory implies that life evolved (and continues to evolve) randomly, or by chance
is not random- by chance
- Evolution results in progress; organisms are always getting better through evolution.
yes, to increase their fitness and adopt to its ecological condition
- Individual organisms can evolve during a single lifespan
Evolution appears at the rate of population
- Evolution only occurs slowly and gradually.
no, it changes a lot, mutation, efficient rate, genetic diversity
- Because evolution is slow, humans cannot influence it.
sometimes occurs quickly. And since humans often cause major changes in the environment, we are frequently the instigators of evolution in other organisms.
- Genetic drift only occurs in small populations.
Genetic drift has a larger effect on small populations, but the process occurs in all populations
- Natural selection is not operating on humans currently.
no
- Species are distinct natural entities that can be easily recognized by anyone
Many of us are familiar with the biological species concept, which defines a species as a group of individuals that actually or potentially interbreed in nature. That definition of a species might seem cut and dried — and for many organisms (e.g., mammals), it works well — but in many other cases, this definition is difficult to apply. F8. Species are distinct natural entities that can be easily recognized by anyone
- Natural selection involves organisms trying to adapt.
environmental pressure- natural selection does not give it to them
- Natural selection acts for the good of the species.
no, fitness organism
- The fittest organisms in a population are those that are strongest, healthiest, fastest, etc.
no, the one who survives is the fitness
12.Natural selection is about survival of the very fittest individuals in a population.
you have to be the fitness- higher chance of survival
- Natural selection produces organisms perfectly suited to their environments.
no, if true there will not be variation (mutation and SR)
