Biological Diversity

Examining Diversity

Notes

Over 1.5 million species of animals and 350 000 species of plants are identified species

Estimate 30 million to 100 million kinds of organisms existing today

Species: 

A group of organisms that have the same structure and can reproduce with one another

Biological Diversity:

All different types of organisms on Earth

All living things:

1. Made of cells

2. Need energy

3. Grow and develop

4. Reproduce

5. Have adaptations

A lil' grade 7 science review

ECOSYSTEM :

Particular environment where living things interact with other biotic an abiotic things (Ex. Boreal Forest)

POPULATION :

 Group of individuals of the same species living in the same area

COMMUNITY :

Populations of different species living in the same area (biotic component of an ecosystem)

• Genetic diversity refers to the variations between members of a population (ex. Banded snail – colouring and banding on shell)

• Some variations are not visible (ex. Human blood types – A, B, AB, O)

Classifying Biological Diversity

Taxonomy:

The science of naming, describing and classifying organisms. It includes all plants, animals and microorganisms of the world.

Invented by Swedish botanist Carolus Linnaeus in the 18th century he developed a system for naming and classifying organisms.

Linnaeus would classify organisms based on common characteristics creating a hierarchy!

He used Latin as a common scientific language combining 2 words to name each living things:

• 1st name is the genus (ALWAYS Capitalized)

Example: A dog is part of the genus Canis

• 2nd name is the species (NEVER Capitalized)

Example: Within the genus Canis there is a species closely related to dogs which is called lupus

Therefore a dog’s taxonomic name is Canis lupus, or C. lupus

No two species have the same name, although closely related species can have the same genus (ex. Canis rufus (redwolf) and Canis lupus (dog))

This taxonomic hierarchy

Kings - Play - Chess - On - Fine - Green - Silk

We use a 5 kingdom system:

Each kingdom groups organisms based on common characteristics

1. Animalia (animals)

2. Plantae (plants)

3. Fungi (yeasts, moulds, mushrooms)

4. Protista (single celled organisms)

5. Monera (bacteria)*

*some scientists split this into 2 – Archaebacteria and Eubacteria

Activity!

Create a taxonomic hierarchy for candy bars using characteristics common to candy bars to categorize different candy bars.

Here’s an exemplar

Interdependence

All species are dependent on other species (with a few plants as the exception)

SYMBIOSIS : 

Association between members of different species (sym = together, bio = life)

Three types of symbiosis:

1.COMMENSALISM : 

One of the participating organisms benefits, but the other does not; however there is no harm done to the second organism (ex. Bird nest in a tree or barnacles on a whale)

2. MUTUALISM  :

Benefits both organisms (ex. Lichen in the arctic is actually fungus and algae – algal cells produce food for both through photosynthesis and the fungus protects the algal cells from dehydration)

3. PARASITISM :

One organism benefits and the other is harmed but not killed  (ex. Tapeworm in intestines, or Mexican beetle is a plant parasite, beetle is parasitized by tachinid fly, which is parasitized by the icheumon wasp)

INTERSPECIES COMPETITION :

When two or more species need the same resources (Food, water, etc.)…This is NOT parasitism

NICHE :

Role of an organism within an ecosystem (i.e., what it eats, its habitat, nesting site, range)

Generalist niche species - fills many roles, usually lives in a broad territory, is said to have a “broad niche”

Specialist niche species - has only a few roles, usually lives in a small amount of territory, is said to have a “narrow niche”

RESOURCE PARTITIONING : 

Division of resources among two or more co-existing species such that the niche of each species differ slightly

Checkpoint 1

Variation Within a Species

VARIABILITY :

Different characteristics within a species

• When there is a great deal of variation the more likely some individuals will survive environmental changes (ex. Predators, climate, disease, etc.)

• Variations that allow a species to survive are called adaptations, there are structural and behavioural adaptations

• ex. Different colour coats blend with different environments for the fox or resistance to penicillin in bacteria

NATURAL SELECTION  :

Occurs when the environment “selects” which individuals will survive long enough to reproduce

As species reproduce characteristics are passed from parents to offspring

• Scientists look at which characteristics of species are passed from generation to generation and those factors that may be affected by the environment

HERITABLE CHARACTERISTICS :

Passed from generation to generation (ex. Eye colour, hair type, skin colour)

NON-HERITABLE CHARACTERISTICS :

Not passed from generation to generation (ex. Playing the piano is acquired)

DISCRETE VARIATION :

Variation in a heritable characteristic that has an either/or form, such as being albino or not being albino

CONTINUOUS VARIATION :

Variation in a heritable characteristic that fall within a range such as height

• Some variation results from interactions with the environment (ex. Plant in the sun vs. plant in the shade or height being affected by diet)

 Asexual and Sexual Reproduction

ASEXUAL REPRODUCTION :

Reproduction without the fusion of sex cells resulting in identical offspring and parent

BINARY FISSION : 

Type of asexual reproduction in amoebas and other organisms in which a parent cell divides into 2 identical cells (only in single celled organisms such as bacteria and protista)

BUDDING : 

Type of asexual reproduction in which a new organism develops from an outgrowth or bud on the parent

• Will be identical to parent

• Occurs in yeast, coral, hydra

SPORES :

A cell produced by asexual reproduction in certain organisms such as fungi, and non flowering plants such as ferns.

• Develop quickly into an adult

• Produced by the division of cells by the parent, not by the union of 2 cells

• Offspring is identical to parent

VEGETATIVE REPRODUCTION :

Type of asexual reproduction in plants that does not involve the formation of a seed

• cuttings

• tubers

• shoots

• sap suckers

The Birds and the Bees

SEXUAL REPRODUCTION :

Reproduction involving the exchange of genetic material between two individuals resulting in offspring that are genetically different from the parents

• Most species of plants and animals reproduce sexually

• Mix of characteristics of the two parents in the offspring

• Male and female in humans and other mammals, but also flowering plants and corals

GAMETE :

Sex cell, either male or female that can unite with another to form a fertilized cell (zygote) that can develop into a new individual. Considered to be Haploid (only a single set of chromosomes, not a pair)

Sexual Reproduction In Animals

SPERM CELL :

Male sex cell (gamete) in humans it has 23 chromosomes

EGG CELL (OVA) :

Female sex cell (gamete) in humans it has 23 chromosomes

FERTILIZATION :

Union of a female sex cell and male sex cell

ZYGOTE :

First cell created by the joining of the gametes, which then divides. It has 46 chromosomes in humans (23 from egg, 23 from sperm)

CLEAVAGE : 

First divisions of a fertilized egg

EMBRYO :

An undeveloped organism in its early development (all cells in an embryo have 46 chromosomes) 

Sexual Reproduction In Plants

• Most plants produce both male and female gametes

• However some plants will only produce only one type of gamete

Male Parts

STAMEN :

Male part of the flower

ANTHER :

Part of the flower that produces pollen and stores it 

POLLEN :

Fine yellow powder on the anthers of flowers, consisting of grains that contain male gametes

Female Parts

PISTILS :

Refers to the entire female reproductive organ of the flower

STIGMA :

Female part of a flower, which receives pollen

STYLE : 

Structure that supports the stigma and connects it with the ovary of a plant

OVARY :

Female reproductive organ in which egg cells are produced, the structure contains the ovules, and develops as the fruit of flowering plants

OVULES :

Sac containing the female gametes of a plant

Checkpoint 2

POLLINATION :

Transfer of pollen from anther to stigma

CROSS POLLINATION :

When the pollen of one plant is carried to the stigma of another by wind, water, or animals

CROSS FERTILIZATION :

When a grain of pollen produces a long tube that eventually grows down the style into the ovary and the 2 gametes join to form a zygote

• Zygote forms into an embryo located inside a seed

• Seed provides protection for the embryo and stores food

Advantages and Disadvantages of Asexual Reproduction

Advantages

• Does not require specialized cells

• Can produce lots of individuals quickly if the conditions are good

• Does not require a minimum population

Disadvantages

• If conditions become unfavourable, the entire population could be wiped out (extinction)

• Limits variation within the species

Advantages and Disadvantages of Sexual Reproduction

Hyla versicolor - Tree frog variation, all of the same frog.

Advantages 

• Provides lots of variation which helps a species survive environmental change

• Increases diversity of organisms

Disadvantages

• Requires a lot of energy and therefore produces a limited number of offspring

• Requires finding a partner

• Requires specialized sex cells

• Requires a minimum population to reproduce

Organisms that do not play by the rules

• Many plant organisms reproduce both sexually and asexually

• Some animals can reproduce both ways:

  Aphids – females produce females without fertilization during the summer. In the fall, when the temperatures drop, males and females are produced and they reproduce sexually

  Corals can reproduce buds, and reproduce sexually

• Some plants develop seeds without the contribution of sperm cells (ex. Some grasses, sunflowers, etc.)

Checkpoint 3