Gifford Pinchot, the first Chief of the United States Forest Service, is widely regarded as the father of American conservation due to his instrumental role in establishing the nation's forest reserves and promoting sustainable forestry practices.

Aldo Leopold, an American ecologist and forester, is best known for his book 'A Sand County Almanac', which explores the relationship between humans and the natural world and advocates for a land ethic that respects the integrity of ecological systems.

Rachel Carson, a marine biologist and conservationist, wrote the groundbreaking book 'Silent Spring' in 1962, which exposed the harmful effects of pesticides, particularly DDT, on the environment and human health.

John Muir, a Scottish-American naturalist and conservationist, founded the Sierra Club in 1892. The organization has played a crucial role in advocating for the protection of wilderness areas and promoting environmental conservation.

Stephen Mather, an American businessman and conservationist, is widely recognized for his efforts in establishing the National Park Service in 1916. He served as the first director of the agency and was instrumental in expanding the national park system.

John Muir, a Scottish-American naturalist and conservationist, is renowned for his passionate advocacy for the preservation of wilderness areas. He played a pivotal role in establishing Yosemite National Park and other protected areas, and his writings inspired many to appreciate the beauty and importance of the natural world.

Theodore Roosevelt, the 26th President of the United States, is widely regarded as the father of wildlife conservation in the country. He established numerous national parks and wildlife refuges, and his policies helped protect endangered species and promote responsible hunting practices.

Aldo Leopold, an American ecologist and forester, is renowned for his work on the concept of ecological succession, which describes the natural changes that occur in plant and animal communities over time. His writings and research contributed significantly to the field of conservation biology.

Gifford Pinchot, the first Chief of the United States Forest Service, is credited with establishing the first national forest in the country, the Shoshone National Forest in Wyoming, in 1891.

Aldo Leopold, an American ecologist and forester, is renowned for his work on the concept of the 'land ethic', which emphasizes the ethical responsibility of humans to respect and care for the natural world.

Rachel Carson, a marine biologist and conservationist, is widely regarded as the father of the modern environmental movement. Her book 'Silent Spring', published in 1962, raised public awareness about the harmful effects of pesticides and sparked a global movement for environmental protection.

Edward O. Wilson, an American biologist and naturalist, is renowned for his work on the concept of 'biodiversity', which refers to the variety of life on Earth. He has been instrumental in promoting the importance of biodiversity conservation and has written extensively on the subject.

Michael Soulé, an American biologist and conservationist, is widely regarded as the father of the field of conservation biology. He has played a pivotal role in developing the scientific foundation for conservation practices and has been a leading advocate for the protection of biodiversity.

G. David Tilman, an American ecologist, is renowned for his work on the concept of 'ecosystem services', which refers to the benefits that humans derive from ecosystems. He has conducted extensive research on the relationship between biodiversity and ecosystem functioning and has been a strong advocate for the conservation of natural ecosystems.

Herman Daly, an American ecological economist, is widely regarded as the father of the field of ecological economics. He has been a leading advocate for the integration of ecological principles into economic decision-making and has written extensively on the need for sustainable economic development.