portugal science test, 8th grade pt

1.abiotic factors (Page 62)

abiotic factors, are the non-living elements of an ecosystem. These factors influence the survival, distribution, and behavior of living organisms. The main abiotic factors are:

• Light – Essential for photosynthesis and affects animal behavior.

• Water – Needed for biochemical reactions, nutrient transport, and habitat formation.

• Temperature – Regulates metabolism and adaptation in organisms.

• Soil – Determines the types of plants that can grow in an area, affecting the entire food chain.

  

2. Fatores abióticos e ecossistemas (Page 64)

Abiotic factors play a crucial role in defining ecosystems. Different ecosystems exist due to variations in abiotic conditions. Examples include:

• Deserts – High temperatures, low water availability, and sandy soils support drought-resistant plants like cacti.

• Tropical Rainforests – High rainfall, warm temperatures, and nutrient-rich soil allow for dense vegetation and biodiversity.

• Tundras – Low temperatures, frozen soil, and little precipitation limit plant growth to mosses and lichens.

• Freshwater vs. Marine Ecosystems – Differences in salinity, temperature, and oxygen levels determine the types of aquatic life present.

3. Influência da luz (Page 66)

Light is a fundamental abiotic factor that influences ecosystems in several ways:

Effects on Plants:

• Photosynthesis – Plants use sunlight to produce energy, forming the base of the food chain.

• Photoperiodism – Some plants flower or bear fruit only under specific light conditions.

• Adaptations to Light – Plants in dense forests have large leaves to capture more light, while desert plants have small leaves to reduce water loss.

Effects on Animals:

• Circadian Rhythms – Many animals follow a daily activity pattern influenced by light (e.g., diurnal vs. nocturnal animals).

• Migration and Reproduction – Birds migrate based on daylight changes, and some species reproduce in specific light conditions.

Effects on Ecosystems:

• Primary Production – More sunlight leads to higher plant growth, supporting larger populations of herbivores and predators.

• Seasonal Changes – In some regions, light availability changes with the seasons, affecting food availability and animal behavior.

4. Influência da água (Page 71)

Water is vital for all life and influences ecosystems in various ways:

Effects on Organisms:

• Essential for Life Processes – All living things need water for chemical reactions, temperature regulation, and nutrient transport.

• Adaptations to Water Availability –

  • Desert animals like camels store water and have efficient kidneys.

  • Aquatic plants have air spaces to float and absorb oxygen.

Effects on Ecosystems:

• Ecosystem Type – The amount of water determines whether an area is a desert, grassland, or forest.

• Water Cycle – Water moves between the atmosphere, land, and bodies of water through evaporation, condensation, and precipitation.

• Droughts and Floods – These extreme conditions can lead to population decline, migration, and changes in species composition.

Water Quality and Life:

• Freshwater vs. Saltwater – Different species are adapted to different salinity levels.

• Pollution – Contaminated water can affect entire ecosystems, leading to loss of biodiversity.

5. Influência da temperatura (Page 76)

Temperature affects all living organisms by influencing metabolism, survival, and geographical distribution.

Effects on Organisms:

• Enzyme Activity – Enzymes function best within a specific temperature range; extreme temperatures can slow down or stop biological processes.

• Cold Adaptations – Polar bears have thick fur and fat layers; some frogs produce antifreeze-like substances in their blood.

• Heat Adaptations – Desert animals are nocturnal to avoid daytime heat; plants have deep roots to reach underground water.

organisms based on their adaptation to water, light, and environmental conditions