Chapter 4: Evolution, Biological Communities, and Species Flashcards

Question

Stabilizing Selection

Answer 1

Narrows the range of a trait. For example, a plant that is too short may not be able to compete with other plants for sunlight. However, extremely tall plants may be more susceptible to wind damage, so the plants are maintained at a medium height.

Answer 2

The population's trait shifts toward one extreme over the other. For example, using the familiar example of giraffe necks, there was a selection pressure against short necks, since individuals with short necks could not reach as many leaves on which to feed. As a result, the distribution of neck length shifted to favor individuals with long necks.

Answer 3

In disruptive selection, selection pressures act against individuals in the middle of the trait distribution. For example, imagine a plant of extremely variable height that is pollinated by three different pollinators, one that was attracted to short plants, another that preferred plants of medium height and a third that visited only the tallest plants. If the pollinator that preferred plants of medium height disappeared from an area, medium height plants would be selected against and the population would tend toward both short and tall, but not medium height plants.

Answer 4

evolution is still at work today, especially with germs. Germs evolve rapidly and become resistant to antibiotics. So, vancomycin is the treatment of last resort because if resistance were to become widespread, we would have no protection from infections

Answer 5

the study of types of organisms and their relationships

Answer 6

last two names for organisms; genus and species; names are in Latin. Ex. Human – Homo sapiens; Corn – Zea mays

Answer 7

There are 6 kingdoms of life: animals, plants, fungi, protists, bacteria and archaebacteria.

Answer 8

an antagonistic relationship within a biological community; resources may be in limited supply requiring organisms to compete for them Examples of limited resources are: * energy and matter in usable forms (including food) * living space * sites for specific activities.

Answer 9

competition between organisms of the same species.

Answer 10

competition between organisms of different species

Answer 11

* the young of the year disperse * species exhibit strong territoriality and force offspring or trespassing adults out of the vicinity * species accomplish resource partitioning between generations

Answer 12

photosynthetic plants and algae (usually)

Answer 13

\*anything that eats organic matter created by other organisms ``` include herbivores (plant eaters), carnivores (meat eaters), omnivores (plant and meat eaters), scavengers (eats only dead animals/plants), detritivores (eats decaying organic material), and decomposers (break down dead or decaying organisms). ```

Answer 14

any organism that feeds directly on another **_living_** organism \*As prey species mature, their predators will change \*predators will change prey is another food source becomes more abundant

Answer 15

one organism benefits through receiving nutrition and there is no benefit to the host or prey.

Answer 16

a superior competitor in a habitat builds up a larger population than its competing species; predators of the superior competitor take note and increase their hunting pressure on the superior species, reducing its abundance and allowing the other weaker competitor to increase in numbers

Answer 17

* Toxic chemicals * Body armor * Extraordinary speed * Ability to hide (camo) * Plants may have thorns, spines, thick bark, bad tastes, or secrete harmful chemicals.

Answer 18

two species (predator and prey especially) exert selective pressure on each other and gradually evolve new features or behaviors together Example, predators become better at searching and feeding and prey become better at escaping and avoiding

Answer 19

harmless species may resemble poisonous or distasteful ones to avoid getting eaten Example: Monarch Butterfly (bad taste to birds) and the Viceroy Butterfly (which can look like Monarch Butterfly)

Answer 20

two species look alike and both are unappealing (like dead leaves) or dangerous (like similar looking bright colored poison frogs); both benefit because predators learn to avoid either species

Answer 21

2 or more species living closely together; sometimes the relationship can most of the time be helpful or it can be harmful to at least one of the species. They often enhance the survival of one or both partners.

Answer 22

a symbiotic relationship between individuals in which both species benefit from the association Example: the acacia ant colonies and the acacia tree

Answer 23

type of symbiosis in which one member clearly benefits and the other is apparently neither benefited nor harmed Example: mosses on trees

Answer 24

a form of predation that may also be considered symbiosis because of the dependency of the parasite on its host

Answer 25

a species that plays a critical role in a biological community that is out of proportion to its abundance. it is usually the top predator, but it can be anything from plants, to microbacteria, to a kind of fish

Answer 26

rate of biomass production (it indicates the rate of solar energy converted to chemical energy; 1,000 kcal/m²/year) Highest Levels: tropical forests, coral reefs, and estuaries (marsh regions) Lowest Levels: deserts, arctic tundra, high up mountains (anywhere where there are low levels of photosysthesis rates)

Answer 27

25%-75% is reflected 0.1%-0.2% is used to produce carbohydrates \*most of the light absorbed is converted into heat and lost into the environment

Answer 28

Abundance is total number of organisms in a biological community. Diversity is number of different species, niches, and genetic variation present

Answer 29

Abundance and diversity are usually inversely related. So, while moving from the equator toward the poles, diversity decreases and abundance within species increases . Example: the Arctic has huge numbers of insects but few species

Answer 30

Climate and history are important factors. For example, Greenland had such a harsh climate that the need to survive through the winter or escape to milder climates becomes the single most important critical factor that overwhelms all other considerations and severely limits the ability of species to specialize or differentiate into new forms. All in all, because of its history, it hasn't had enough time to diversify.

Answer 31

refers to patterns of spatial distribution of both individuals and populations within a community; it also refers to the relation of a particular community to its surroundings The types of ecological stuctures are distributed randomly, clumped together, or are in highly regular patterns.

Answer 32

the number of species at each trophic level and the total number of trophic levels in a community Example: If species are clustered with few trophic levels and simple food chains, the complexity will not be high

Answer 33

* Constancy (lack of fluctuations in composition or functions) * Inertia (resistance to perturbations) * Renewal (ability to repair damage after disterbances)

Answer 34

he proposed that the more complex and interconnected a community is, the more stable and resilient it will be in the face of disturbance because if many species occupy the same trophic level, then if one disappears, the others can just fill in for its place

Answer 35

boundary/relationship between one habitat and another. The boundary is usually sharp and distinct. Examples: Forest to grassland, ocean to shore

Answer 36

the name for the boundary itself between adjacent communities

Answer 37

There are closed communities where the boundry is sharply divided, and there are open communities where the boundries are gradual or indistinct.

Answer 38

Communities develop, grow, and change over time. The community that developed last and lasted the longest is the climax community. It is complex and stable.

Answer 39

organisms begin to make home to a location that has been barren. Ex.sandbar, volcanic flow, mudslide, etc.

Answer 40

an existing community is disturbed and a new one develops

Answer 41

the first “colonists” in primary succession. May be microbes, mosses, lichens, etc.

Answer 42

any force that disrupts the established patterns of species diversity and abundance, community structure or properties; these forces can be natural or man-made. Disturbances generally benefit species because it sets back supreme competitors and allows less-competitive species to persist.

Answer 43

Introducing non-native species can cause severe disturbances in an ecological community and can alter the community. Example: Mongooses in Hawaii were brought to control rats but instead killed native birds

Answer 44

New species introduced to an ecosystem can disturb the delicate balance that exists between the original inhabitants. These invasive species sometimes end up dominating existing species and wiping them out, reducing overall biodiversity with not just the extinction of that species, but other species dependent on it too.

Answer 45

Biological Activity

Answer 46

The most productive ecosystems are tropical rain forests and estuaries. The least productive ecosystems are desert and open ocean. The units to quantify biomass accumulation are 1,000/kcal/m²/year.