Environment Shapes Traits
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Middle School Life Science › Environment Shapes Traits
A plant species grows in two habitats. Habitat W is windy and dry; Habitat S is sheltered and moist. In Habitat W, plants with waxy leaves produced 40 seeds per plant on average, while plants with thin leaves produced 15. In Habitat S, plants with thin leaves produced 38 seeds per plant, while plants with waxy leaves produced 20. Which explanation shows how environmental conditions affect which trait is advantageous, using the evidence?
Because both habitats have plants, leaf traits do not affect success; all plants should reproduce equally.
Plants in the windy habitat grew waxy leaves because they needed them, and plants in the moist habitat grew thin leaves because they wanted to absorb more water.
Waxy leaves are always better because they look tougher, so they should produce more seeds in both habitats.
The windy, dry habitat is linked to higher seed production for waxy-leaf plants (40 vs. 15), while the sheltered, moist habitat is linked to higher seed production for thin-leaf plants (38 vs. 20), so the environment influences which leaf trait is advantageous.
Explanation
The core skill is understanding how the environment shapes which traits are advantageous for survival and reproduction in a species. Environments differ in weather and moisture, like windy dry habitats versus sheltered moist ones. Evidence shows different trait success, with waxy-leaf plants producing more seeds in dry areas (40 per plant) and thin-leaf in moist (38 per plant). To check this, assess seed production metrics for traits in each habitat type. A common misconception is that plants grow specific leaves because they 'need' or 'want' them, but advantages come from inherited traits succeeding better. When environments change, such as a moist area drying out, waxy leaves might become favored. In this way, changing environments redefine trait advantages over generations.
A scientist studies the same species of lizard on two islands. Island R has many hawks (predators) and rocky ground. Island L has few hawks and lots of leafy plants. After marking 200 lizards of each type on each island, the scientist finds:
- Island R: 70% of lizards with long legs survived 3 months; 35% of lizards with short legs survived.
- Island L: 60% of lizards with short legs survived 3 months; 40% of lizards with long legs survived. Which claim about environment and traits is incorrect?
Because Island R has many hawks, the hawks caused individual lizards to grow longer legs during the 3 months so they could escape.
The environment influences which leg-length trait is advantageous because survival patterns differ between Island R and Island L.
Evidence links each island’s conditions to different survival outcomes for long- and short-legged lizards.
Long legs may be advantageous on Island R, while short legs may be advantageous on Island L, based on the survival percentages.
Explanation
The core skill is understanding how the environment shapes which traits are advantageous for survival and reproduction in a species. Environments differ in factors like predator presence and terrain, such as hawk-filled rocky islands versus leafy ones with few predators. Evidence shows different trait success, with long-legged lizards surviving better on rocky islands (70%) and short-legged ones on leafy islands (60%). To check this, analyze survival percentages for traits in each environment to determine which confers an advantage. A common misconception is that environments cause individuals to alter their traits, like growing longer legs, but selection acts on existing variations. If environments change, such as more predators invading a leafy island, short legs might become less favored. Consequently, evolving environments can reverse which traits are most successful over time.
A species of beetle lives in two environments. In a dark forest, 80 out of 100 dark-colored beetles survived one month, while 30 out of 100 light-colored beetles survived. On a pale sandy beach, 25 out of 100 dark-colored beetles survived, while 75 out of 100 light-colored beetles survived. Which explanation shows how the environment affects which trait has an advantage, using the evidence?
The forest environment is linked to higher survival for dark beetles (80/100), while the beach environment is linked to higher survival for light beetles (75/100), so the environment influences which color trait is advantageous.
Survival is determined only by the environment, not by traits, so the color differences do not matter.
Beetles changed their color during the month because each environment demanded the color they needed to survive.
Dark color is the best trait for beetles in every environment because it is stronger, so it should have the highest survival everywhere.
Explanation
The core skill is understanding how the environment shapes which traits are advantageous for survival and reproduction in a species. Environments differ in features like color and texture, such as dark forests versus pale sandy beaches. Evidence shows different trait success, for example, dark-colored beetles have higher survival in forests (80/100) while light-colored ones succeed more on beaches (75/100). To check this, compare survival rates of traits across environments to see which trait links to higher success in each. A common misconception is that one trait is always best everywhere, but advantage depends on the specific environment. When environments change, such as a beach becoming darker, the favored traits may shift accordingly. Overall, this means that as conditions vary or evolve, different traits become advantageous for the population.
The same species of rabbit lives in two areas. In a snowy field, rabbits with white fur produced an average of 6 offspring per adult each season, while rabbits with brown fur produced 2. In a brown grassland, rabbits with brown fur produced 5 offspring per adult, while rabbits with white fur produced 2. Which statement about trait advantage is supported by the evidence?
White fur is always more advantageous because it looks cleaner and healthier than brown fur.
Rabbits choose their fur color each season depending on what they want to blend into.
Fur color advantage depends on the environment: white fur has higher success in snow, and brown fur has higher success in grassland.
All rabbits will eventually become white because snow is a harder environment and forces the species to improve.
Explanation
The core skill is understanding how the environment shapes which traits are advantageous for survival and reproduction in a species. Environments differ in conditions like snowfall in fields versus brown grass in plains. Evidence shows different trait success, such as white-furred rabbits producing more offspring in snowy areas (6 per adult) while brown-furred ones do better in grasslands (5 per adult). To check this, examine reproduction rates for each trait in different settings to identify patterns of advantage. A common misconception is that animals choose or change their traits to match the environment, but traits are inherited and selected by success. When environments change, like a grassland becoming snowy, the advantageous traits may shift to favor white fur. Thus, changing environments continually reshape which traits provide the best survival and reproductive edge.
A bird species lives in two places. City parks have many hard seeds; coastal wetlands have mostly soft insects. In the city parks, birds with thick beaks ate enough food to raise chicks in 55 out of 70 nests, while birds with thin beaks succeeded in 20 out of 70 nests. In the wetlands, thin-beaked birds succeeded in 50 out of 70 nests, while thick-beaked birds succeeded in 25 out of 70 nests. Which statement about trait advantage is supported by the evidence?
Thin beaks are morally better because they do not harm insects as much, so thin-beaked birds should succeed more in all places.
The environment influences which beak trait is advantageous: thick beaks have higher nesting success in city parks, while thin beaks have higher nesting success in wetlands.
Birds can decide to grow thicker or thinner beaks during the nesting season depending on what food is available.
Only the type of place (city or wetland) determines success, so beak traits are not evidence for differences in survival or reproduction.
Explanation
The core skill is understanding how the environment shapes which traits are advantageous for survival and reproduction in a species. Environments differ in food sources, such as hard seeds in city parks versus soft insects in wetlands. Evidence shows different trait success, with thick-beaked birds raising more chicks in parks (55/70 nests) and thin-beaked in wetlands (50/70). To check this, review nesting success rates tied to traits across locations. A common misconception is that birds can choose to change beak thickness seasonally, but traits are fixed and selected by environmental fit. If environments change, like wetlands gaining hard seeds, thick beaks could gain advantage. Thus, environmental variations continually influence which traits are most beneficial.
A fish species lives in two lakes. Lake A has clear water; Lake B has muddy water. In Lake A, 90 out of 120 fish with bright stripes survived a season, while 50 out of 120 fish with dull coloring survived. In Lake B, 40 out of 120 bright-striped fish survived, while 85 out of 120 dull-colored fish survived. What evidence best links environment to trait success?
Clear water is better than muddy water, so fish in Lake A survive more because the lake is nicer.
Fish survival depends on luck, so the color differences are not useful evidence.
In Lake A, bright stripes have higher survival (90/120) than dull coloring (50/120), but in Lake B, dull coloring has higher survival (85/120) than bright stripes (40/120).
Bright stripes are more attractive, so they must always lead to higher survival regardless of the lake.
Explanation
The core skill is understanding how the environment shapes which traits are advantageous for survival and reproduction in a species. Environments differ in clarity, like clear lakes versus muddy ones affecting visibility. Evidence shows different trait success, with bright-striped fish surviving more in clear water (90/120) and dull-colored ones in muddy water (85/120). To check this, compare survival numbers across traits and environments to link conditions to advantages. A common misconception is that brighter traits are always superior due to attractiveness, but success varies by context. When environments change, such as a clear lake becoming muddy, dull coloring might gain the advantage. This illustrates how shifting environments redefine favorable traits in populations.
A scientist compares the same species of snail in two streams. Stream F has fast-moving water; Stream S has slow-moving water. After a flood season, the scientist records:
- Stream F: 72% of snails with a low, flat shell stayed attached to rocks; 30% of snails with a tall shell stayed attached.
- Stream S: 65% of tall-shell snails stayed attached; 50% of flat-shell snails stayed attached. Which claim about environment and traits is incorrect?
The evidence shows that trait success changes with environmental conditions, so the environment influences which trait is advantageous.
Different shell shapes can have different success depending on the stream conditions, as shown by the different percentages.
Flat shells may provide an advantage in fast water, while tall shells may provide an advantage in slow water, based on the attachment data.
Because the fast stream is dangerous, it created flat shells in the snails so they could survive the flood season.
Explanation
The core skill is understanding how the environment shapes which traits are advantageous for survival and reproduction in a species. Environments differ in water flow, like fast streams versus slow ones impacting attachment. Evidence shows different trait success, with flat-shell snails staying attached more in fast water (72%) and tall-shell in slow (65%). To check this, examine attachment percentages for shell types in varying stream conditions. A common misconception is that harsh environments create new traits in individuals, like flattening shells, but they select for pre-existing ones. When environments change, such as a slow stream speeding up, flat shells might become more advantageous. This demonstrates how altering environments can switch favored traits in species.
A frog species lives in two ponds. Pond P has many fish predators; Pond N has no fish predators. In Pond P, 18 out of 60 tadpoles with a spotted pattern survived to become frogs, while 5 out of 60 plain-pattern tadpoles survived. In Pond N, 40 out of 60 plain-pattern tadpoles survived, while 22 out of 60 spotted-pattern tadpoles survived. Which statement about trait advantage is supported by the evidence?
Since Pond P and Pond N are both ponds, pattern cannot affect survival; only being a frog matters.
Spotted tadpoles survive more in Pond P, while plain tadpoles survive more in Pond N, so the environment (presence of predators) influences which pattern trait is advantageous.
Spots are always better because they look more complex, so spotted tadpoles should survive the most in both ponds.
All tadpoles will become spotted over time because predators make species improve by giving them the trait they need.
Explanation
The core skill is understanding how the environment shapes which traits are advantageous for survival and reproduction in a species. Environments differ in threats, like ponds with fish predators versus those without. Evidence shows different trait success, with spotted tadpoles surviving more in predator ponds (18/60) and plain in non-predator (40/60). To check this, evaluate transformation rates to frogs for patterns in each pond type. A common misconception is that predators cause species to develop needed traits over time, but they select among existing variations. When environments change, such as adding predators to a safe pond, spotted patterns might gain advantage. Hence, shifting environments can change which traits are most successful for survival.
The same species of moth lives in two forests. Forest 1 has dark tree bark because of soot. Forest 2 has light tree bark. In Forest 1, 65% of dark-winged moths survived to reproduce, while 20% of light-winged moths survived. In Forest 2, 60% of light-winged moths survived to reproduce, while 25% of dark-winged moths survived. Which prediction about trait success is supported if Forest 2 becomes darker over many years due to soot?
Dark-winged moths are likely to have higher survival in the darkened Forest 2 than they did before, because dark wings were more successful in the dark-bark forest.
Light-winged moths will remain the most successful everywhere because being light is a universally best trait.
Light-winged moths will automatically turn dark as soon as the bark darkens, because the environment creates the needed trait.
Trait differences do not matter; only the amount of soot determines which moths survive.
Explanation
The core skill is understanding how the environment shapes which traits are advantageous for survival and reproduction in a species. Environments differ in elements like bark color due to soot, such as dark forests versus light ones. Evidence shows different trait success, with dark-winged moths surviving better in sooty forests (65%) and light-winged in clean ones (60%). To check this, evaluate reproduction survival rates for traits in varying conditions. A common misconception is that traits automatically change to match new environments, but selection favors existing traits. If environments change, like a light forest darkening with soot, dark wings could become more advantageous. Therefore, environmental shifts can alter which traits promote the most success.
The same species of mouse lives in two regions. Region C has cold winters; Region H has hot summers. In Region C, 68 out of 100 mice with thick fur survived the winter, while 35 out of 100 mice with thin fur survived. In Region H, 70 out of 100 thin-fur mice survived the summer, while 40 out of 100 thick-fur mice survived. Which explanation shows how the environment affects which trait has an advantage, using the evidence?
Mice grew thicker or thinner fur during the season because they needed to match the temperature in their region.
The cold region is linked to higher survival for thick-fur mice (68/100), while the hot region is linked to higher survival for thin-fur mice (70/100), showing that the environment influences which fur trait is advantageous.
Thick fur is a universal best trait because it provides more protection, so it should be advantageous in both regions.
Temperature alone determines survival, so fur traits are not relevant evidence.
Explanation
The core skill is understanding how the environment shapes which traits are advantageous for survival and reproduction in a species. Environments differ in temperature, such as cold winter regions versus hot summer ones. Evidence shows different trait success, with thick-fur mice surviving better in cold (68/100) and thin-fur in hot (70/100). To check this, compare seasonal survival rates for fur types in each climate. A common misconception is that animals grow fur thickness in response to needs, but environmental selection acts on inherited traits. If environments change, like a hot region cooling, thick fur could become more favored. Accordingly, environmental changes reshape which traits offer the greatest advantages.