Life Sciences Revision Grade 10

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Questions and Answers

Which type of slope experiences warmer and drier conditions?

North-facing slopes

West-facing slopes

South-facing slopes (correct)

East-facing slopes

What effect does a steep slope have on water run-off?

Slows down water run-off

Increases water absorption

Reduces soil erosion

Accelerates water run-off (correct)

Which of the following soil types has a low water retention capacity?

Sandy soil (correct)

Peaty soil

Clay soil

Loam soil

Which factor contributes to the infertility of soil on a steep slope?

Shallow soil depth Signup and view all the answers

What is humus primarily composed of?

Decayed plant material Signup and view all the answers

What role do nitrifying bacteria play in the nitrogen cycle?

Convert ammonia into nitrates Signup and view all the answers

How does carbon dioxide return to the atmosphere?

Through cellular respiration, decomposition, and combustion Signup and view all the answers

What is meant by biodiversity?

The variety of life forms on Earth Signup and view all the answers

Which scientist developed the two-kingdom classification system?

Carl Linnaeus Signup and view all the answers

In the classification of organisms, what are kingdoms divided into in animals?

Phyla Signup and view all the answers

What is the Kingdom classification for a lion?

Animalia Signup and view all the answers

In the binomial naming system, how is the genus name written?

In uppercase with the species in lowercase Signup and view all the answers

Which classification level comes after Phylum in the hierarchy?

Class Signup and view all the answers

What type of key is commonly used to classify living organisms?

Dichotomous key Signup and view all the answers

Which of the following classifications corresponds to the pine tree?

Class: Gymnospermae Signup and view all the answers

What is the defining characteristic of the division Pteridophyta?

They include ferns Signup and view all the answers

What does the term 'Coniferales' refer to?

An order of cone-bearing plants Signup and view all the answers

How many kingdom classifications are listed in the five-kingdom system?

Five Signup and view all the answers

What is the role of producers in a food chain?

They produce their own food. Signup and view all the answers

What forms the second trophic level in a food chain?

Primary consumers Signup and view all the answers

How is energy transferred within a food chain?

Some energy is lost at each trophic level. Signup and view all the answers

What do pyramids of biomass represent?

The total mass of organisms at each trophic level. Signup and view all the answers

What is a characteristic of tertiary consumers?

They feed on other carnivores. Signup and view all the answers

Which trophic level has the greatest amount of energy?

Producers Signup and view all the answers

What primarily shows the actual number of organisms at each trophic level?

Pyramid of numbers Signup and view all the answers

Which of the following describes decomposers in a food chain?

They can exist at any trophic level. Signup and view all the answers

What phenomenon is responsible for forming nitrates in the atmosphere?

Lightning Signup and view all the answers

When did the Cenozoic era begin?

66 million years ago Signup and view all the answers

Which mass extinction took place towards the end of the Palaeozoic era?

Permian-Triassic extinction Signup and view all the answers

Approximately how many families of species died out at the end of the Palaeozoic era?

90% of all families Signup and view all the answers

What is the method of dating fossils using radioactive isotopes called?

Carbon dating Signup and view all the answers

What do we call the study of the distribution of individual species?

Biogeography Signup and view all the answers

Which supercontinent is evident from diagram studies?

Pangaea Signup and view all the answers

Which organism's fossil remains are found on all the shown land masses?

Mesosaurus Signup and view all the answers

What is Carbon 14 dating primarily used for?

Measuring the age of fossils younger than 50,000 years Signup and view all the answers

According to relative dating, where would you find the oldest rocks?

Below the upper layers of sediment Signup and view all the answers

What is the binomial name of a lion?

Panthera leo Signup and view all the answers

What classification level comes just above 'species' in Linnaeus' system?

Family Signup and view all the answers

How would the removal of a hyena affect the ecosystem?

Disruption of food chains Signup and view all the answers

Which of the following features characterizes the Cape floral kingdom?

Home to indigenous and endemic species Signup and view all the answers

What is a major threat to the flora of the Cape floral kingdom?

Habitat destruction Signup and view all the answers

What percentage of plant species in the Cape floral kingdom are considered endemic?

70% Signup and view all the answers

Study Notes

Life Sciences Revision Booklet - Grade 10

This revision program helps students revise critical content and skills from terms 3 and 4.
The goal is for students to understand key concepts and apply the knowledge for the examination.
The topics covered include: Biosphere to ecosystems, Biodiversity and classification, and History of life on Earth.

Biosphere to Ecosystems

Biosphere: The part of Earth where living organisms occur. It's made of the atmosphere, lithosphere, and hydrosphere.
- Atmosphere: The air surrounding Earth, a mixture of gases (e.g., nitrogen, oxygen, carbon dioxide).
- Lithosphere: Earth's outermost layer, including soil and rocks.
- Hydrosphere: All the water on Earth (oceans, seas, lakes, rivers, etc.), both fresh and salt water.
Biomes: Large geographical areas with similar climates and geographic features, supporting specific types of plants and animals.
- Types of biomes: Terrestrial (land) and aquatic (water).
- South African examples: Fynbos, forest, grasslands, savannah, thicket, Nama Karoo, succulent Karoo, and desert.
- Aquatic biomes are either freshwater or marine (saltwater).

Biodiversity and Classification

Biodiversity: The variety of life forms on Earth.
History of Classification:
- Simple systems are based on physical characteristics.
- The five-kingdom system (proposed by Robert Whitaker in 1969) is the most commonly used.
- Two-kingdom system: Linnaeus' system of plants and animals.
- Seven categories: A way to divide kingdoms, including phyla in animals and divisions in plants.
- Dichotomous keys: Used for classifying living organisms.
- Prokaryotes and Eukaryotes: Different types of cells (differences in nuclei and organelles)

History of Life on Earth

Changes in climate (e.g. Ice ages): Long geological periods with drastic decreases in temperatures affecting species.
Geological events: Continental drift (movement of continents), formation of supercontinents (e.g., Pangaea), and the breakup of those continents.
The geological timescale: A timeline of Earth's history, divided into eras (Paleozoic, Mesozoic, and Cenozoic), periods, and epochs.
Fossil formation and dating: -Fossils are remains of organisms, found primarily in sedimentary rock.
- Ideal conditions include burial immediately after death, acidic conditions, and absence of oxygen. -Methods include radiometric and relative dating.
Cambrian explosion: Rapid diversification of life forms during the Cambrian period.
Mass extinctions: Periods when many species disappear within a short period of time. The last was related to the dinosaurs.

Revision Questions

Detailed questions (some higher-order) are listed in the booklet for practice.

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Description

This quiz is designed for Grade 10 students to revise essential content and skills from Life Sciences, focusing on topics like the biosphere, ecosystems, and biodiversity. It aims to enhance understanding and application of key concepts vital for examinations.