Living things can be described based on their features

We classify living things into groups to make sense of the world around us and to communicate about it. The classification system used by scientists today is similar to the one devised by Carolus Linnaeus in the 1700s. He grouped living things on the basis of observable external features and created a ranked hierarchical system of identification. The highest level of classification he identified is the kingdom.

Today, scientists recognise that there are more kingdoms, for example, the kingdom of fungi, the kingdom of plants and the kingdom of animals. Scientists are also working to re-classify species to reflect shared ancestry—to group things that are closely related on a molecular level (DNA) and not just things that look related.

External features of plants

The kingdom of plants is comprised of multicellular organisms that transform the energy of the Sun into chemical energy through photosynthesis. They generally have structures to capture light, for example, leaves, and structures to capture water and nutrients from the environment, for example, roots. Plants rely on external forces to move them from place to place, for example, wind, water or animals dispersing seeds.

Although they vary widely in appearance, virtually all flowering plants have three main parts: roots, a stem, and leaves.

• The root is the part of a plant usually found below ground. Roots anchor the plant in the soil and absorb the water and nutrients it needs to grow.
• The stem is the part of the plant usually found above ground. It provides structural support to lift the leaves up into the sunlight and transports nutrients between the roots and the leaves.
• Leaves are specialised for photosynthesis and are often thin and flat to maximise the amount of sunlight captured for photosynthesis, but they can be a variety of other shapes.

Flowering plants produce flowers and fruit as part of their reproductive cycle. Flowers are the reproductive organs of a plant and usually contain both male and female parts. After fertilisation, the female parts of a flower develop into seed-containing fruits.

External features of animals

The kingdom of animals is comprised of multicellular organisms that must eat other things to survive. They generally have body structures such as claws, teeth and digestive systems for catching and eating their food. All animals are able to move from place to place using internal structures, such as muscles and skeletons, at some stage in their life cycle. More detail is provided in Diverse range of living things/Diversity.

Features and behaviours can aid survival

Looking at an animal or a plant, you can identify structural features and their probable function. For example, some animals have large eyes that allow them to see in darkness and some plants have waxy leaves that help minimise water loss. These features, which are important to the survival of an animal or plant in its native environment, are called adaptations. Adaptations can also be behaviours, such as the instinct to run from danger or the unfurling of leaves when sunlight hits them.

Generally, scientific adaptations are identified at a population level; one individual with a difference is a mutant who might survive better in the environment. If the individual’s children inherit the trait and also survive better in the environment, then the mutation will gradually become ‘normal’ in the population and be considered an adaptation.

The ‘environment’ for a population is the physical habitat, for example, a desert, and also the community of other livings things in which it lives. For example, the abilities of predators determine the adaptations of prey: if a species’ main predator has eyes that primarily detect motion then the instinct to freeze when spotted is an adaptation to that ‘environment’.

Science seeks to justify with evidence and reasoning why features or behaviours can be considered adaptations to an environment. The desert environment is good for studying adaptations to survive because it is so harsh and so it is rare to find features and behaviours that don’t help a population’s survival. Many desert species are ‘specialists’ (adapted to live in the specific conditions of the desert, for example, the thorny devil) rather than generalists (adapted to live in most environments with varying degrees of success, for example, common rats).

Some plants have adaptations to deal with salinity. For example, mangroves can secrete excess salt through salt glands in their leaves. Although not a complete solution to the problem of salinity in Australia, some crossbred hybrid species of rice and wheat grow reasonably well in low levels of salty water.

More information on adaptations can be found at Diverse range of living things/Adaptations.

The form and features of living things are related to the functions that their body systems perform.

This list of alternative conceptions is not meant to be comprehensive, but instead aims to provide a starting point.

Alternative conception	Accepted conception
Plants take in all the substances they need to grow through their roots.	Plants obtain water and trace nutrients through their roots. Gases (carbon dioxide and oxygen) are obtained by all parts of the plant (including leaves).
All animals can move independently from one place to another.	Animals need to eat their food/nutrients and most are able to move independently in reaction to their environment. Animals are multicellular; their cells are different from plant cells. Some underwater organisms (sea anemone) have animal cells but are stationary like a plant.
Animals live on land.	There are many animals that live in the water.
Living things adapt by changing to suit their environment.	Adaptations are a result of survival and reproduction of the individuals in a species that are most suited to their environment. This process can take many generations. (Species adapt, not individual organisms.)
All features of living things are adaptations.	While most features are adaptations that improve survival, some are a result of previous ancestors. An example of this is wisdom teeth in humans. Adaptations provide a selection/survival advantage for an organism.
All animals have four legs and fur.	Reptiles (scales) and insects (>4 legs) are animals.
All animals have skeletons.	Animals are broken into two main groups. Vertebrates all have an internal spinal cord that is usually surrounded by a ‘backbone’. The second group is invertebrates, many of which (insects and spiders) have an external skeleton. Some animals (jellyfish) do not have any skeletons.
Spiders are insects.	Both spiders and insects (ants etc) belong to the group of invertebrates. Ants and other insects belong to the class ‘Insecta’ while spiders belong to the class ‘Arachnida’.
Fruit is grown for us to eat.	Fruit is grown around a plant's seeds to attract animals that will spread the seeds over a wide area.
Plants have flowers and stems.	Flowering plants have organs (flowers, leaves, stems, and roots). Other plants (ie conifers and mosses) do not have typical flowers.
Pollination is the same as seed dispersal.	Pollination is a mechanism for plants to use sexual reproduction and provide for variation in the species. Seed dispersal allows seeds to spread over a wider area and prevent competition between plants.
Plants have flowers to attract insects.	Flowers provide opportunity for the pollen (sperm equivalent) to travel to the ovum (egg). Insects or birds are attracted to aid this process.
Plants make nectar so that bees can make honey.	Nectar is produced by plants to attract insects, birds or bats. As insects travel from flower to flower, they transfer pollen and support the sexual reproduction of the plant.
All flowers are the same.	Each flowering plant produces a flower that is unique.
Only leaves photosynthesise.	Some non-woody green stems can photosynthesise.
The life cycle is the same as a reproductive cycle.	Some animals only have a single reproductive cycle and therefore this will be the same as their life cycle. Other animals have more than one reproductive cycle in the life span.

 

References

AITSL. (n.d.). Resource. AITSL. https://www.aitsl.edu.au/tools-resources/resource/dispelling-scientific-misconceptions-illustration-of-practice

Allen, M. (2019). Misconceptions in Primary Science 3e. McGraw-hill education (UK).

Ideas for Teaching Science: Years 5-10. (2014, April 14). Resources for Teaching Science. https://blogs.deakin.edu.au/sci-enviro-ed/years-5-10/

Pine, K., Messer, D., & St. John, K. (2001). Children's misconceptions in primary science: A survey of teachers' views. Research in Science & Technological Education, 19(1), 79-96.

Redhead, K. (2018). Common Misconceptions. Primary Science Teaching Trust. https://pstt.org.uk/resources/common-misconceptions/

University of California. (2022, April 21). Correcting misconceptions - Understanding Science. Understanding Science - How Science REALLY Works... https://undsci.berkeley.edu/for-educators/prepare-and-plan/correcting-misconceptions/