Biology
Topic 2

Natural Classification

Based on evolutionary relationships
and genetic similarities

Classification changes over time...

New species may not fit into any categories, so hard to know where to place it.
New research may indicate some species aren't as closely related as we thought.

Kingdom
Phylum
Class
Order
Family
Genus
Species

Evolution is a continuous process

Organisms are changing all the time, so they way they have been classified may have to change. Sometimes they eve form a new species.

Asexual Reproduction

Reproduces by making a copy of itself. It does not interbreed with any other organism, so don't fit the definition of a 'species.'

Common Ancestors

Similar species tend to have common ancestors. They may look alike and have similar habitats.
However, some species have adapted to their environment, e.g Llamas and Camels

Interspecific Competition

Organisms compete for resources against another species.

(Bigger Impact)

Parasites

Live of a host. Take what they need to survive, and don't give anything back. Often harms the host. (Mosquitos)
Win-Lose Relationship

Adaptations

The features that organisms have to make them better suited to their environment.
more able to compete, meaning more likely to survive and reproduce.

Generalists

Organisms that have adapted to suit a range of different habitats.

Organisms that can live in the cold have adapted in many ways to reduce heat loss.

They keep warm by...

Large size and compact body shape to give a smaller surface area to volume ratio.
This means that less body heat will be lost through the skin.

Behavioural Adaptations

To escape the cold, organisms...

Migrate to warmer climates
Hibernate
Huddle together

Behavioural Adaptation to Hot

- Spend time in the shade or underground
- Be active at night, when it's cooler
- Bathing in water. As the water evaporates it transfers the heat from the skin to surroundings.

Dry Environments (Plants)

Have a rounder shape, smaller surface area.
Thick waxy cuticle and spines instead of leaves to reduce water loss.
Extensive roots, for a large surface area, and they also store water in their stems.

Charles Darwin
-He knew that organisms showed wide variation, and had to compete for resources.
- Concluded that those that were best adapted would be more successful.
"Survival of the Fittest" Theory.

Lamarck had a conflicting view...

he said that if a acharctaeristsic was used a lot, the organism would develop it, this developed characteristic would be passed onto off spring. e.g. a rabbit with big leg muscles has babies with big leg muscles.

People now accept Darwin's theory because...

Theory has been debated and tested by a range of scientists.
No one's managed to prove this wrong.

Decomposition
recycling of carbon and other nutrients takes longer in water logged conditions. this is because of the fungi and bacteria that decompose the nutrients need oxygen. Water logged soils don't have much oxygen, so the decomposers have less energy- therefore taking longer.

Human Impact on the Environment

Increase in population causes

1. Global Warming
2. Acid Rain
3. Ozone Depletion

Acid Rain

When fossil fuels and waste materials are used up, they release gas called sulfur dioxide, which reacts with water, making sulphuric acid. this damages soil and trees, buildings and aquatic life.

Indicator Species

MAYFLY LARVAE

water quality. Cant survive in dirty water. cleaner the water, greater number of mayfly larvae there will be.

Advantage of using a living indicator

Quick
Cheap
No need for expensive equipment or trained workers

Advantage of using non-living methods

- Reliable, numerical results
- Easy to compare between sites
- Exact pollutants can be identified.

Endangered Species

Species that are in danger of becoming extinct.

Conservation Programmes

2. Ensuring Minimal Damage to Food Chains

If one species becomes extinct, it means it will affect the whole food chain. Conservation programmes ensure that they conserve one species in the hope that they may help others survive.

4. Cultural Aspects

Individual species my be important to a nation or an area's cultural heritage, e.g America's Bald Eagle is conserved as a national symbol.

Development has to be sustainable

WHALES: COMMERCIAL VALUE DEAD OR ALIVE...