Module 3 Flashcards
(22 cards)
What is selective pressure?
External agents which affect an organism’s ability to survive in a given environment; influences the evolution of living organisms via natural selection.
What happens to organisms when they go through natural selection? (Focus on favourable/unfavourable characteristics)
Organisms with unfavourable characteristics to survive in their environment pass away, not being able to reproduce. Contrastingly, organisms containing the favourable characteristics to survive in their environment can live for longer periods of time and can thus reproduce and produce offspring with similar favourable characteristics.
Selective pressures:
- can be negative (decreasing the occurrence of a trait)
- can be positive (increases the proportion of a trait)
Types of selection pressures include:
- Resource availability
- Environmental conditions
- Biological factors
How does resource availability affect species in an environment through selection pressures?
Resource availability can influence a species’ survival as it refers to the presence of sufficient food, habitat (shelter/territory) and mates (reproduction). Without these, the species can readily decrease in numbers.
Predict the effects of selection pressures on organisms in ecosystems, including biotic and abiotic factors.
Selection pressures are factors that alter biodiversity. Positive selection pressures increase the likelihood of a particular species or a particular variation of a species surviving to reproduce. Negative selection pressures decrease the likelihood of a particular pieces or particular variation of a species surviving to reproduce. Abiotic selection pressures: changes in gas availability, pH and access to sunlight. Biotic selection pressures include presence of predators, diseases and competition among species.
Examine the adaptations of organisms that increase their ability to survive in their environment, including structural, physiological and behavioural adaptations.
Structural: form a part of the physical features of an organism. e.g size, fur, colour, shape, etc.
Physiological: relate to how the organism works. e.g mammals produce milk for their young, funnel web spiders kill their prey by injecting poison, etc.
Behavioural: changes to an organisms behaviour in order for them to better live in their environments. e.g wombats spending most of the day in a burrow, elephants cooling themselves by immersing their bodies in water, etc.
How do environmental conditions affect species in a given environment (selection pressures)?
The temperature, weather conditions and the geographical access of an environment can affect species, as some of them may not be able to handle the temperature and the weather conditions of their ecosystem. This is going to cause selection pressures and therefore will cause evolution by natural selection.
Biotic factors impacting selection: (effect species can have on other species)
- their behavioural characteristics come from predator/prey relationships. Name the 7 organism relationships.
- Mutualism
- Commensalism
- Competition
- Paracitism
- Amensalism
- Neutralism
- Predation
What is mutualism
Mutualism : both species benefit from each other positively
Commensalism
One species benefits while the other remains neutral
Paracitism
One species benefits from this bond while the other is negatively affected (harmed)
Neutralism
Both species remain unaffected; neutrally affected
Amensalism
One species is affected negatively while the other is neutrally affected (not affected)
Competition
Both species are negatively affected by this bond.
Predation
One species is positively affected (predator) while one species is negatively affected (prey)
What is structural adaptation in both plants and animals?
Structural adaptations are the physical changes of species to suit their environment. For example, camouflage can help animals go undetected by predators in their environment. Therefore species that are better camouflaged in the environment are more likely to reproduce and that causes a favourable trait to develop in the offspring, allowing them to structurally adapt to become better at camouflaging.
Plants such as mangroves have structurally adapted to control the amount of salt that travels through their stems by adapting to have big, waxy and moist leaves that block salt from travelling upwards as well as roots that can expel the excess salt back into the water.
What are physiological adaptations in both animals and plants?
Physiological adaptation is an internal body process to regulate and maintain homeostasis for an organism to survive in the environment in which it exists, examples include temperature regulation, release of toxins or poisons and releasing antifreeze proteins to avoid freezing in cold environments.
Physiological adaptations of plants are processes which allow them to compete. An example of this is the formation of poisons for defence. The nettle plant stings us when we brush the tiny needles on its leaves, which contain poison.
What are behavioural adaptations of plants and animals?
Behavioural adaptations in animals is something an animal does usually in response to some type of external stimulus in order to survive. Hibernating during winter is an example of a behavioral adaptation.
Behavioural adaptations are something an organism does to improve its survival. An example of this in plants is how they grow towards the sun, or close their leaves during hot times in the day.
What is the impact of abiotic factors in an ecosystem as well as the relationship between abiotic and biotic factors in that ecosystem?
Abiotic factors are especially important because they directly affect how organisms survive. All living forms within an ecosystem are considered biotic factors. These organisms depend on abiotic elements since they have a direct impact on their development, survival, and procreation. One abiotic element that significantly impacts aquatic ecosystems is turbidity. High turbidity levels prevent submerged plants from growing.
What is the impact of biotic factors, (including predation, competition and symbiotic relationships) in their relationship with abiotic factors in an ecosystem?
The number of organisms in the prey and predator species has a profound effect on the landscape and other factors of the ecosystem. Too few predators means more prey and less vegetation. There may even be competition between predators for prey and land. Symbiotic relationships are important for ecosystem function because they help to maintain balance and stability. For example, mutualistic relationships can increase biodiversity by allowing different species to coexist and thrive.
How do the ecological niches occupied by species affect the relationships between biotic and abiotic factors of an ecosystem?
Ecological niches allow different species to live together. Each species knows its position in the ecosystem as well as the food chain. The number of niches in an ecosystem determines the number of species in it, that is, they define the diversity of the place.
An ecological niche is the role and position a species has in its environment; how it meets its needs for food and shelter, how it survives, and how it reproduces. A species’ niche includes all of its interactions with the biotic and abiotic factors of its environment.
