Adaptation to environments

• Habitat


  Habitat refers to the place where a community, species, population, or organism lives. This can include both the geographical and physical locations, as well as the type of ecosystem they inhabit.
• Adaptations of organisms


  A grass species adapted to sand dunes may have deep, extensive root systems to anchor itself and absorb water in the dry, sandy environment. A tree species adapted to mangrove swamps may have specialized roots called pneumatophores that stick up above the water to allow the tree to get oxygen.
• Abiotic variables


  Abiotic variables like temperature, light, pH, and soil composition can all affect where a species is able to live and thrive. The range of tolerance of a species to these limiting factors determines its distribution.

  When studying species distribution, look for correlations between the presence/absence of a species and the measured abiotic variables in that habitat.
• Range of tolerance of a limiting factor

  1. Use transect data to correlate the distribution of plant or animal species with an abiotic variable

  2. Collect data from a natural or semi-natural habitat

  3. Use sensors to measure abiotic variables such as temperature, light intensity and soil pH
• Conditions required for coral reef formation

  Coral Reefs are a great example of a marine ecosystem that has specific abiotic requirements for formation, including:

  • Water depth
  • pH
  • Salinity
  • Water clarity
  • Temperature

  These abiotic factors must fall within a certain range for coral polyps to be able to build and maintain the reef structure.
• Biomes


  Groups of ecosystems with similar communities due to similar abiotic conditions and convergent evolution
• Terrestrial biomes


  • Tropical forest
  • Temperate forest
  • Taiga
  • Grassland
  • Tundra
  • Hot desert
• Adaptations to life in hot deserts

  • Cacti
  • Fennec fox
• Adaptations to life in tropical rainforest

  • Spider monkey
  • Blue poison dart frog
  • Philodendron
• Abiotic Factors and Terrestrial Biome Distribution

  The distribution of terrestrial biomes (like tropical forests, grasslands, deserts, etc.) is largely determined by two key abiotic factors:

  Temperature × Precipitation = Biome Type

  We can plot this relationship on a graph to see how different biomes are distributed based on these climatic variables.

  Convergent evolution also plays a role, as similar abiotic conditions in different regions can lead to the development of analogous ecosystems.
• Biomes and Convergent Evolution


  Biomes are groups of ecosystems with similar communities that have developed due to:

  1. Similar abiotic conditions (e.g. climate)
  2. Convergent evolution - where organisms in different regions evolve similar adaptations in response to analogous environmental pressures.
• Population


  A group of organisms of the same species, living together in the same area at the same time, and can interbreed
• Community


  Different populations of organisms living together in the same place at the same time, and interacting with each other (e.g. predator-prey, competition, parasitism)
• Ecosystem


  The community and its abiotic environment (abiotic means non-living parts of the environment)
• Biosphere


  All areas in, on and above the earth where life can be found
• Adaptations of mangrove trees - Red mangrove

  • Prop roots (pneumatophores) to absorb oxygen
  • Cable roots near surface for oxygen
  • Roots filter salt from seawater
  • Adapted to tidal differences
  • Buoyant seeds for dispersal
  • Seed embryo grows before dropping
  • Can secrete excess salt
  • Accumulation of minerals and sugars
• Abiotic factors affecting plants and animals

  • Temperature
  • Water availability
  • pH
  • Light intensity and duration
  • Salinity
  • Soil composition
• Coral reefs are important as they are home to 25% of all marine species, even though they only cover less than 1% of the ocean's surface area
• Coral reefs


  • Not too deep since corals need light for their symbiotic algae which make food for the living coral animals (coral gives the algae a place to live in return = mutualism)
• pH- Coral reef


  • Cannot have too low pH, and the calcium carbonate skeletons of corals cannot form in low pH, and can even dissolve in too low pH
  • Increased CO2 emissions are threatening corals, since the CO2 in the air can dissolve into the oceans - creating carbonic acid, lowering the pH
• Clarity- Coral reef


  • Water needs to be clear for the symbiotic algae (zooxanthellae) to get enough light for photosynthesis
  • Pollution from land use can make the water too cloudy for the algae
• Temperature- Coral reef


  • Very narrow range of temperature (20-28C)
  • Global warming is threatening the coral - they "bleach" = get lighter and lose their color and die if the water is too warm (The algae leave the coral)
• Salinity- Coral reef


  • Need a certain range
  • Rivers flowing into the sea can bring too much fresh water, lowering the salinity, so the coral cannot grow in that immediate area
• Biome


  A large geographical area with groups of ecosystems with similar communities due to similar abiotic conditions (temperature and rainfall) and convergent evolution
• Convergent evolution


  When species that are not closely related evolve the same types of adaptations needed for the habitat, or their nisch (roll in the community)
• Convergent evolution examples


  • Marsupial wolf and regular wolf both have strong jaws since they are a top predator
  • Bats and birds have wings to fly
  • Cactus in America and euphorbias in Africa have similar traits since they both live in the desert
• Biome conditions


  • Temperature
  • Precipitation
  • Light intensity
  • Seasonal variation
  • Communities
• Tropical rainforest biome


  • Temperature: High (20-25°C)
  • Precipitation: High (2000-10000 mm/year)
  • Light Intensity: High
  • Seasonal Variation: Minimal
  • Communities: High plant and animal diversity; nutrient-poor soils
• Hot desert biome


  • Temperature: High
  • Precipitation: Very low
  • Light Intensity: High
  • Seasonal Variation: Minimal variation
  • Communities: Little vegetation, often spiny, adapted for water conservation
• Saguaro cactus (Carnigiea gigantea)


  Cacti have evolved a series of remarkable adaptations to survive in the harsh conditions of hot deserts. Here are key adaptations:

  Waterproof Thick Waxy Cuticle

  Leaves Reduced to Spines

  Long Deep Tap Root

  Massive Shallow Root System

  Fat Stems with Spongy Tissue

  Pleated Stems

  Upright Growth

  CAM Metabolism (Crassulacean Acid Metabolism)
• Fennic fox (Vulpes zerda)


  • Large ears with many blood vessels to let heat made from cell respiration in its body cells escape - cools them
  • Large ears to locate underground prey
  • Nocturnal to avoid daytime heat - builds underground dens to sleep during the day
  • Can obtain most of their water from food, without having to drink
  • Kidneys are adapted to dry - most water in their urine is reabsorbed back into the blood - hardly ever urinates
  • Pale color coat to reflect sunlight
  • Long thick hair helps both during hot days and cold nights
  • Hairs on foot pads to protect feet from hot sand in the daytime
  • Variable ventilation rate - can go up to 600 breaths per minute to cause heat loss
• Kapok tree (Ceiba pentandra)


  • Can grow very tall to outcompete other plant species for sunlight
  • Strong buttress roots that extend above the ground to help support the tall tree trunk. Needed for the shallow soil of the rainforest
• Poison dart frogs


  • Produce toxic chemicals/poisons in skin to protect from predators such as snakes and lizards that are plentiful in the rainforest
  • Warning coloration to warn predators that they are poisonous. Predators learn that these colors are dangerous, so frogs are protected
  • Lay eggs in water: lots of water in rainforests, and the leaves of trees catch water so they can lay their eggs in the water in the leaves in the upper canopy of the forest
• Invasive species


  Species not native to an area, but which has moved in by itself, or has been brought in by humans or other animals
• Natural selection and evolution

  There is variation in the organisms in a population, and those with the best characteristics will survive better and have more surviving young. These good traits or adaptations will be passed to their young with genes (heritability). In time, the characteristics of a population may change. Habitats change as well, so populations must be able to adapt to changing conditions
• Waterproof Thick Waxy Cuticle

  • Function: Prevents water loss.
  • Mechanism: The waxy layer acts as a barrier, reducing evaporation from the plant's surface.
• Leaves Reduced to Spines- Saguaro cactus


  • Function: Reduces surface area for water loss by transpiration and provides defense against herbivores.
  • Mechanism: Spines minimize surface area, thus reducing water loss, and deter animals from eating the cactus.
• Long Deep Tap Root- Saguaro cactus

  • Function: Gathers water from deep underground.
  • Mechanism: The tap root can reach depths of up to 1 meter, accessing water that is not available to plants with shallower roots.
• Massive Shallow Root System- Saguaro cactus


  • Function: Captures water from occasional rainfalls.
  • Mechanism: The extensive root system, which can span up to 30 meters in diameter, quickly absorbs water from the soil surface.
• Fat Stems with Spongy Tissue

  • Function: Stores water.
  • Mechanism: The spongy tissue within the stems can hold large quantities of water, which the cactus can use during dry periods.