Question

What are some of the opportunities and challenges to life on land? What were some of the first colonizers? How did this process occur?

Answer 1

Answer :

Human life depends on the earth as much as the ocean for our sustenance and livelihoods. Plant life provides 80 percent of the human diet, and we rely on agriculture as an important economic resources. Forests cover 30 percent of the Earth’s surface, provide vital habitats for millions of species, and important sources for clean air and water, as well as being crucial for combating climate change.

Every year, 13 million hectares of forests are lost, while the persistent degradation of dry lands has led to the desertification of 3.6 billion hectares, disproportionately affecting poor communities.

Forests cover nearly 31 per cent of our planet’s land area. From the air we breathe, to the water we drink, to the food we eat–forests sustain us. Think about it. Around 1.6 billion people depend on forests for their livelihood. Almost 75 per cent of the world’s poor are affected directly by land degradation. And of the 8,300 animal breeds known, 8 per cent are extinct and 22 per cent are at risk of extinction. Biodiversity and the ecosystem services it underpins can also the basis for climate change adaptation and disaster risk reduction strategies as they can deliver benefits that will increase the resilience of people to the impacts of climate change. Forests and nature are also important for recreation and mental well-being. In many cultures, closely linked to spiritual values, religious beliefs and traditional teachings.

While 15 percent of land is protected, biodiversity is still at risk. Nearly 7,000 species of animals and plants have been illegally traded. Wildlife trafficking not only erodes biodiversity, but creates insecurity, fuels conflict, and feeds corruption. Urgent action must be taken to reduce the loss of natural habitats and biodiversity which are part of our common heritage and support global food and water security, climate change mitigation and adaptation, and peace and security.

OPPORTUNITIES & CHALLENGES

We need to be better informed about impacts to lands, prioritize our land resources differently and take a long term approach to how we value species, habitats and lands as vital components of our human ecosystem.

• Increasing productivity:

As global population and incomes increase, demand for food, shelter, products and services will put pressure on land resources and will require that we do more within the limits of the planet. Targeted conservation: Currently, protected land areas are not sufficient to protect biodiversity, and often these lands are not those in most need of protection. Additionally, the interaction of climate change and human activities makes it challenging to track discrete causes and subsequent impact of conservation efforts.

• Intelligent land management and policy setting:

Target 15.9 calls for the incorporation of ecosystem and biodiversity values into national and local planning which could be supported by technological development in government planning systems.

• Track and monitor destructive activities:

Over-hunting, overfishing and over-harvesting contribute greatly to the loss of biodiversity, and are responsible for the demise of numerous species over the last several hundred years. Poaching and other forms of hunting for profit increase the risk of extinction; the demise of an apex predator can result in catastrophic consequences for ecosystems.

• Limited funding:

Despite advancements in capability and application of digital technology in the conservation space, funding has long posed a challenge. Given the high cost of many of these technologies (e.g. drones, data analytics software) it will be difficult to implement these technologies at the scale needed without widespread investment from the public and private sectors. Just as the causes of these environmental challenges are many and varied, demonstrating the impact of a singular project or solution can often prove difficult. Also, skilled researchers and analysts will be required to demonstrate the benefits of technology solutions so that investment continues.

The Colonization of Land

Changes in the environment of the early Earth drove the evolution of organisms. As prokaryotic organisms in the oceans began to photosynthesize, they produced oxygen. Eventually, oxygen saturated the oceans and entered the air, resulting in an increase in atmospheric oxygen concentration, known as the oxygen revolution approximately 2.3 billion years ago. Therefore, organisms that could use oxygen for cellular respiration had an advantage. More than 1.5 years ago, eukaryotic cells and multicellular organisms also began to appear. Initially, all of these species were restricted to the oceans of Earth.

The first organisms to live on land were photosynthetic prokaryotes that inhabited moist environments near ocean shores. Despite the lack of water, terrestrial environments offered an abundance of sunlight and carbon dioxide for photosynthesis. Around 500 million years ago, the ancestors of nowadays plants were able to colonize drier environments, but they required adaptations to prevent dehydration. They developed methods for reproduction that did not depend on water and protected their embryos from drying out. These early plants furthermore evolved a vascular system that included roots to acquire water and nutrients and a shoot to obtain sunlight and carbon dioxide.

Plants and fungi appear to have colonized land at the same time. Their coevolution onto land is the result of the mutually beneficial relationship between many plants and fungi, seen in both modern organisms and some of the earliest plant fossils; Fungi aid in the absorption of nutrients and water while benefiting from the nutrients provided by the plant.

Arthropods were the first animal species to colonize land, around 450 million years ago. The first tetrapods later evolved to live on land as well, finding an abundance of food in the plant species that had colonized the land. Amphibians dominated terrestrial animal life for 100 million years. Later, dinosaurs and then mammals would become the most abundant terrestrial animals.