Question

1. List the 7 characteristics of living things and provide a definition of each. Fig 1.1
2. Distinguish among the three domains of life.
3. After being given a description of a living organism be able to appropriately classify which domain it belongs to.
4. List and distinguish among the three kingdoms of multicellular, eukaryotic life. (Plants, Animals, Fungi)

Answer 1

Living things are organism which possess life .characteristics of living things is as follows-

1-Nutrition -Living things take in materials from their surroundings that they use for growth or to provide energy. Nutrition is the process by which organisms obtain energy and raw materials from nutrients such as proteins, carbohydrates and fats

2- Respiration- Respiration is the release of energy from food substances in all living cells. Living things break down food within their cells to release energy for carrying out the following processes

3- Movement - All living things move. It is very obvious that a leopard moves but what about the thorn tree it sits in? Plants too move in various different ways. The movement may be so slow that it is very difficult to see

4-Excretion - All living things excrete. As a result of the many chemical reactions occurring in cells, they have to get rid of waste products which might poison the cells. Excretion is defined as the removal of toxic materials, the waste products of metabolism and substances in excess from the body of an organism

5- Growth -Growth is seen in all living things. It involves using food to produce new cells. The permanent increase in cell number and size is called growth.

6-Reproduction - All living organisms have the ability to produce offspring

7- Sensitivity - All living things are able to sense and respond to stimuli around them such as light, temperature, water, gravity and chemical substances.

All of life can be divided into three domains based on the type of cell of the organism.

1. Bacteria cells do not contain a nucleus.

2. Archaea cells do not contain a nucleus

3. Eukarya cells contain a nucleus.

Archea and bacteria both domains composed of small single celled organisms and seem very similar, but they also have significant differences. Both are composed of prokaryotic cells, which are cells without a nucleus.

In addition, both domains are composed of species that reproduce asexually (asexual reproduction) by dividing in two. Both domains also have species with cells surrounded by a cell wall, however, the cell walls are made of different materials. Bacterial cell walls contain the polysaccharide  peptidoglycan.

Lastly, Archaea often live in extreme environments including hot springs, geysers, and salt flats. Bacteria do not live in these environments.

Eukarya  All of the cells in the domain Eukarya keep their genetic material, or DNA, inside the nucleus.

	Archaea	Bacteria	Eukarya
Multicellular	No	No	Yes
Cell wall	Yes without peptidoglycan	Yes with peptidoglycan	Varies plants and fungi have a cell wall animals do not
Nucleus (membrane bound organelles)	No	No	Yes

Domain Eukarya is made up of four kingdoms Protista, fungi, Plantae and Animalia.

Plants belongs to kingdom plantae and includes green, brown and red algae liverworts, mosses, ferns, and seed plants with or without flowers. they are multicellular eukaryotes with chlorophyll in the photosynthetic regions. cells have a large central vacoule and rigid cell wall composed of cellulose , nutrition is typically autotrophic , plants are mostly nonmobile being anchored to the substratum.

life cycle consist of alternating haploid gametophyte and diploid sporophyte generation.

Animals

they are multicellular eukaryotes without chlorophyll , most animals have organ system level of organisation

their cells lack cell wall central vacoule and plastids

nutrition is typically holotrophic , animals are mostly mobile

Reproduction is generally sexual . life cycle is dominated by diploid stage

Fungi

they are predominantly multicellular eukaryotes without chlorophyll.

the body of a fungus is filamentous and called mycellium., cell wall is present and composed of chitin.

nutrition is heterotrophic and absorptive due to lack of chlorophyll.

Reproduction is both sexual and asexual