Ecology, Classification and adaptations

• No specific examples of adaptations are required in the exam specification
• Organisms are adapted to living in the natural environment through structural, behavioral, and functional adaptations
• Camels are adapted to the hot and dry conditions of the desert
• Structural adaptations of camels include:

  • Having a hump on their back as a thermal insulator
  • Metabolic reactions that can produce water from fat
  • Thick coat on the upper surface of their body for insulation
  • Leathery inside of the mouth to eat desert plants
  • Long eyelashes to keep dust out of their eyes
  • Wide feet to prevent sinking into the sand
• Functional adaptations of camels include:

  • Producing concentrated urine and dry feces to reduce water loss
  • Tolerating large changes in body temperature to cope with the intense heat of the desert
• Kangaroo rats are nocturnal to avoid daytime heat, live in burrows underground, and have behavioral adaptations to their lifestyle
• Arctic foxes have structural adaptations for cold conditions:

  • Thick fur for insulation
  • Fur on the soles of their feet to reduce heat loss
  • Small ears to reduce surface area and heat loss
  • Coat provides effective camouflage for hunting
• Cacti in the desert have adaptations to reduce water loss:

  • Some cacti have small leaves or no leaves, only spines
  • Extensive and shallow roots to catch water after rainfall
  • Ability to store water in their stem to survive without rain for months
• Extremophiles are organisms adapted to live in extreme conditions like deep-sea vents with high temperatures, pressures, and salt concentrations.
• Linnaeus divided all living organisms into two kingdoms: the animal kingdom and the plant kingdom
• Each kingdom was further divided into smaller categories: kingdom, phylum, class, order, family, genus, and species
• A helpful mnemonic to remember the categories is "Kings Play chess on fancy gold squares”
• Every organism is named using its genus and species, known as the binomial system
• The binomial name for the polar bear is Ursus maritimus
• The classification system is based on observable characteristics such as body shape or number of toes
• Scientists now use the three domain system developed by Carl Woese
• The three domains are:

  • Archaea: primitive bacteria often found in extreme conditions
  • Bacteria: true bacteria like those in the human digestive system
  • Eukaryota: includes animals, plants, fungi, and protists like amoeba
• Evolutionary trees show the relationships between organisms

  • Scientists use classification data, including DNA, for living organisms
  • For extinct organisms, scientists rely on fossils, but the fossil record may be incomplete
• In an evolutionary tree, closely related species share a common ancestor

  • Species 1 and 2 are closely related, while species 3 is more distantly related
• Levels of organization in an ecosystem:

  • Habitat: the environment in which an organism lives (e.g., elephants living in the grasslands of Africa)
  • Population: the total number of organisms of the same species living in the same geographical area (e.g., thousands of elephants in the African grasslands)
  • Community: populations of all different species that live in the same habitat (e.g., zebras, giraffes, gazelles, insects, plants, bacteria, and fungi in the African grasslands)
  • Ecosystem: both the biotic (living) and abiotic (nonliving) parts of an environment and how they interact
• Biotic vs. abiotic parts of an environment:

  • Biotic: the living organisms in an environment
  • Abiotic: the nonliving parts of an environment (e.g., water, minerals in the soil)
• Competition in ecosystems:

  • Plants compete for light, space, water, and mineral ions in the soil
  • Animals compete for food, water, mating partners, and territory
• Interdependence in ecosystems:

  • All species in a community depend on each other
  • Animals depend on other living organisms for food
  • Some living organisms provide shelter for others
  • Plants can depend on animals for pollination and seed dispersal
• Impact of species disappearance:

  • If a species disappears from a community, it can affect the whole community
  • For example, without bees for pollination, many plants would not reproduce, leading to a food shortage for animals that feed on these plants
• Stable community:

  • In a stable community, the populations of organisms are in balance with each other and with abiotic resources like water
• • New pathogens: infectious diseases can emerge and spread, potentially wiping out a population of a species
• Biotic factors:

  • Availability of food: all animals eat other living organisms, such as lions eating other animals and zebras eating plants. The availability of food is a biotic factor that can affect the number of organisms in a community
  • Arrival of a new predator: a new predator can cause the population of a prey species to fall and can also affect existing predators through competition for the same prey
  • Competition between species: if a species is outcompeted, its population can fall to the point where breeding is no longer possible, leading to possible extinction
• Abiotic factors:

  • Light intensity: plants need light for photosynthesis, and if light intensity is too low, the rate of photosynthesis decreases, impacting plant growth and potentially affecting animals that feed on plants
  • Temperature: changes in temperature can cause species distribution to change, leading to migration of animals and disappearance of plant species in an area
  • Water: essential for the survival of both plants and animals, with many species adapted to deal with low water levels
• • Gases (carbon dioxide and oxygen): carbon dioxide is needed for photosynthesis in plants, and a decrease in carbon dioxide levels can impact the rate of photosynthesis. Oxygen is essential for aerobic respiration in organisms, and changes in dissolved oxygen levels in water can harm aquatic organisms like fish
• • pH and mineral content of soil: important for plant growth, as some plants cannot grow in soil that is too acidic or too alkaline, and plants require certain minerals like nitrate for protein production
  • Wind intensity and direction: strong winds can cause plants to lose water, leading to adaptations in plants growing in windy areas like sand dunes
• Definitions!

  • Habitat: the environment in which an organism lives
  • Population: the total number of organisms of the same species living in the same geographical area
  • Community: populations of all different species that live in the same habitat
  • Ecosystem: both the biotic and abiotic parts of an environment and how they interact
• Biotic vs. abiotic parts of the environment:

  • Biotic: living organisms in the environment
  • Abiotic: nonliving parts of the environment like water and minerals in the soil
• Resources that organisms compete for:

  • Plants compete for light, space, water, and mineral ions in the soil
  • Animals compete for food, water, mating partners, and territory
• Interdependence in a community:

  • Every animal depends on other living organisms for food
  • Some living organisms provide shelter for others
  • Plants can depend on animals for pollination and seed dispersal
• Impact of a species disappearing from a community:

  • If a species disappears, it can affect the whole community
  • For example, without bees, many plants would not get pollinated, affecting the food chain
• Stable community:

  • In a stable community, populations of organisms are in balance with each other and with abiotic resources like water
• Food chains represent feeding relationships within a community
• Food chains start with a producer, which is usually a green plant
• Producers synthesize complex molecules like glucose through photosynthesis
• Glucose is passed down the food chain to other organisms as biomass