NATURAL SCIENCE UNIT 4 SUMMARY - ECOSYSTEMS AND LIVING THINGS

 

ECOSYSTEMS AND LIVING THINGS

1.     THE ELEMENTS OF AN ECOSYSTEM

An ecosystem includes all living things (plants, animals, fungi, bacteria, algae…) and non living things (soil, water, air and climate conditions) of a physical environment.

 

The habitat is the place where an organism grows or lives

 

A population is formed by all the individual organisms of the same species

 

A community is formed by the interaction of different populations.

 

 

TYPES OF ECOSYSTEMS (SUMMARY): Review their flora and fauna from the PUPIL’S BOOK and the worksheet we did about it.

1.     TERRESTRIAL ECOSYSTEMS

1.1  FORESTS

A)    Coniferous forests : cold areas

B)    Temperate deciduous forests: temperate areas

C)    Mediterranean forest: warm areas close to the Mediterranean sea

D)   Tropical rainforest: warm and wet areas close to the Equator

 

1.2  GRASSLANDS

A)    Savannahs: tropical zones

B)    Prairies or steppes: colder areas

 

1.3  DESERT: the hottest and driest places or Earth

 

1.4  TUNDRA: cold areas close to the North Pole

 

 

2.     AQUATIC ECOSYSTEMS

2.1  Marine ecosystems: seas and oceans.

A)    shoreline

B)    coral reefs

C)    kelp forest

D)   open ocean

 

2.2  Freshwater ecosystem:

A)Standing water (lakes)

B) flowing water (rivers)

C) wetlands

 

 

3.     ARTIFICIAL ECOSYSTEMS

3.1  Artificial terrestrial ecosystems: farmland, greenhouse, zoo, park, garden

 

3.2  Artificial aquatic ecosystem: ponds, reservoirs, fish farms, aquariums

 

3.3  Urban ecosystems

 

 

2.     FOOD CHAINS AND FOOD WEBS

Autotrophs: Organisms that make their own food. They perform photosynthesis.

 

Heterotrophs: Organisms that feed on other organisms.

 

 

*LEVELS OF A FOOD CHAIN

 

Food chains have three levels: producers, consumers (primary, secondary, tertiary) and decomposers.

 

1- PRODUCERS: first level of the food chain. They are autotrophs.  PLANTS AND ALGAE

 

2-CONSUMERS: they are heterotrophs.

2.1Primary consumers: they feed on producers.  They are herbivores.

2.2Secondary consumers: they feed on primary consumers. They can be carnivores or omnivores

2.3Tertiary consumers: they feed on primary and secondary consumers. They are carnivores (predators)

 

3- DECOMPOSERS:  last level of the food chain. They break down (decompose) organic matter from plants and animals.  FUNGI and BACTERIA.

 

 

*FOOD WEBS

Food webs are interconnected food chains that produce energy in the form of biomass (organic material from plants and animals)

-Producers create more biomass

-Tertiary consumers create less biomass

 

 

*ENDANGERED SPECIES

These species have a very small population because they are hunted or killed and their habitat is destroyed.  When a species in a food web disappears, the whole ecosystem can break down.

 

*INVASIVE SPECIES

These species are introduced and kill or compete with native species. This affects an ecosystem‘s natural balance.

 

 

 

3.     LIVING THINGS AND CELLS

 

Cell: they are the basic form of live.

 

Tissues: Many cells join together to perform the same function.

 

Organs: Different tissues join together forming organs.

 

System: Several organs working together form a system.

 

 

	ANIMALS	PLANTS	FUNGI	PROTISTS (algae)	MONERA (bacteria)
Number of cells	multicellular	multicellular	multicellular	Unicelular or multicellular	unicellular
Cell membrane	yes	yes	yes	yes	yes
Cell Wall	no	yes	yes	yes	yes
Nucleus	yes	yes	yes	yes	no
Tissues	yes	yes	yes	no	no
organs	yes	yes	no	no	no

 

 

	PLANT CELL	ANIMAL CELL
Cell membrane	Yes	Yes
Cell Wall	Yes	No
Cytoplasm	Yes	Yes
Nucleus	Yes	Yes
Mitochondria	Yes	Yes
Vacuoles	Yes (bigger)	Yes (smaller)
Chloroplasts	yes	no

*Plant cell: hexagonal shape.

 

 

*TYPES OF TISSUES

TISSUE	FUNCTION	PART OF THE BODY
Nervous tissue	It is made of nerve cells. Senses and coordination	Brain, spinal cord
Epithelial tissue	Outer layer of the skin and internal organs.	Small intestine and stomach
Muscle tissue	It is made of muscle cells. They can contract of relax	The heart and the biceps
Connective tissue	It supports and connects other types of tissue	Bones, blood, loose connective tissue

 

 

 

 

 

4.ANIMAL AND PLANT KINGDOMS

1.ANIMAL KINGDOM

1.1 VERTEBRATES: They are multicellular and heterotrophs. They have an internal skeleton with a skull and a backbone.

Type of vertebrate	Ecosystem	Physical characteristics	Type of heterotrophs
FISH	Aquatic ecosystems	They have fins, gills, scales and a tail. They are oviparous	Omnivores Carnivores
AMPHIBIANS	They live on land or in the water	They have soft skin and a tail. Tadpoles breathe by gills and adults breathe by lungs. They are oviparous	Carnivores
REPTILES	They live on land or in the water	They have scales, a tail, fangs and claws. They are oviparous	Herbivores and carnivores
BIRDS	All ecosystems	They have a beak, wings, feathers and claws. They are oviparous	Herbivores, omnivores and carnivores
MAMMALS	All ecosystems	They have fur, a tail and claws. They are viviparous	Herbivores, omnivores and carnivores

 

 

 

 

 

2.2 INVERTEBRATES

They don´t have a backbone.

Type of invertebrate	Physical characteristics	Examples
ARTHROPODS	Exoskeleton	Insects (butterfly) Crustacean (crab) Arachnids (spider) Myriapods (centipede)
MOLLUSCS	Soft body	Cephalopods  (squid) Bivalves (mussel) Gastropods (snail)
ECHINODERMS	Soft body and hard internal skeleton	Starfish Sea urchin
ANNELIDS	Soft body	Earthworm Coral Sea sponge

 

 

2. PLANT KINGDOM

2.1 FLOWERING PLANTS

 

Type of flowering plant	Characteristics	Examples
Angiosperms	They have flowers They reproduce sexually They grow fruit and seed They are deciduous	Lemon tree Cherry tree Apple tree
Gymnosperms	They have flowers They reproduce sexually They grow cones and seed They are evergreen	Pine tree Fir tree (conifers)

 

 

2.2 NON-FLOWERING PLANTS

 

Type of non-flowering plant	Characteristics
Mosses	They don´t have flowers They reproduce asexually by spores They don´t have roots They live in wet places in the shadows
Ferns	They don´t have flowers They reproduce asexually by spores They have roots They live in wet places in the shadows

 

 

 

4.     MONERA, PROTIST AND FUNGI KINGDOMS

4.1  MONERA KINGDOM (Bacteria)

They are unicellular

They reproduce asexually

They are prokaryotic (no nucleus)

Examples: salmonella and lactobacilli

 

 

4.2  PROTIST KINGDOM (Algae and Amoebae)

They are unicellular or multicellular

They are eukaryotic (they have a nucleus)

Some algae are autotrophs

Amoebae are heterotrophs

They live in aquatic environment

They move thanks to cilia and flagella

 

4.3  FUNGI KINGDOM (mushroom, yeast and moulds.)

They are unicellular or multicellular

They reproduce asexually by spores

They are eukaryotic

They are decomposers (feed on dead organic matter)

Some fungi are edible and other and poisonous

They can also be parasites (take advantage of another organism: the host)