biol 2200 final exam

range

• determines where organisms are found

• where organisms are found are determined by their ability to persist or perish in different environments

factors that affect range:

• abiotic: temperature, humidity, water/light availability

  • Basic properties of a habitat that will influence where an organism can/cannot live

• biotic: food, habitat requirements, species interactions (e.g. competition, predation)

  • Organisms need food and space to sleep and/or have offspring

  • Interactions can be positive or negative (e.g. competition, predation)

    • Important for determining if an organism can live there

range expansion

new habitat becomes available but old habitat is still occupied

range shift

old habitat becomes unsuitable

ecology

study of organisms’ relationships with their environment

includes:

• distribution and abundance

  • where they are found and how many there are

• biotic and abiotic factors of the environment

what is the relationship between ecology and evolution?

• ecology looks at how organisms interact w/ their environment

• evolution (by natural selection) looks at how populations adapt to their environment over generations

• ecology influences evolution by:

  • organisms that have traits better suited for their environment have higher fitness → drives selection to favor that trait → trait becomes more common

• evolution influences ecology by:

  • new trait emerges in population → trait possibly changes interaction with the environment

difference between ecology and evolution

evolution occurs over multiple generations, ecology occurs within a generation

dispersal

movement of organisms to a new habitat

• organisms may move to escape competition or find new resources

modes of dispersal (how organisms move to disperse)

animals: move actively

• ex: butterflies can migrate across continents

plants: use passive mechanisms (e.g. wind, water, adherent fruits, fleshy fruits) to move seeds

• wind / water: some seeds are aerodynamically designed to be moved across long distances through wind or water

• adherent fruit: seeds have structures that stick to the fur or feathers of animals → allows for the seeds to be carried long distances before falling off on the ground

• fleshy fruit: adaptive function to why fruit is delicious; animals will want to eat the fruit and move it around

  • seeds can pass through digestive systems and germinate where they are defecated

why is dispersal important?

it ensures species can survive if environmental conditions change

distribution patterns within populations

uniform distribution

random distribution

clumped distribution

uniform distribution

• even spacing

• driven by territoriality and competition

  • territoriality: organisms defend specific areas to secure exclusive access to resources (e.g. food, water, shelter, mates)

    • can space individuals evenly across the habitat if the resources are evenly distributed

      • this pattern minimizes overlap and competition

    • ex: hawks defend hunting territories; each hawk claims a specific area w/ certain amount of space → results in even spacing

  • competition for resources: closely spaced individuals compete for resources (e.g. sunlight, nutrients, water)

    • can be direct (ex: one plant casts a shadow over another plant)

    • can be indirect (ex: two plants compete by extracting nutrients or water from a shared area)

    • only plants that are adequately spaced w/ enough distance between them can coexist → leads to uniform distriution

random distribution

• no clear pattern to how individuals are distributed

  • there are so many resources available, so they don’t need to compete

  • ex: dandelions will grow wherever the seeds land in a well-maintained lawn due to abundant resources

clumped distribution